Kurz prežitia v krízových situáciách (vojenský kurz pre civilov)
Vojenská akadémia vo Vyškove 27. 5. - 4. 6. 2008
Bývalá Vysoká vojenská škola pozemného vojska arm. gen. Ludvíka Svobodu si hľadá nové uplatnenie
(Kurz v starších podobách: http://www.army.cz/acr/preziti2006/html/uvod.html
Kurz pre civilných zamestnancov NATO: http://zpravy.idnes.cz/zamestnanci-nato-musi-pred-vyslanim-do-mise-na-tyden-do-ceska-p5a-/zpr_nato.asp?c=A100316_192638_zpr_nato_inc)
Ubytovanie: I 9, izba 507
Výuka: Blok B, 512, kasáreň Dědice; vojenský újezd Březina
Veliteľ kurzu pplk. H
Organizácia: prap. M, prap J, kpt. P
„Veliteľ čaty“: JŠ
2. družstvo: JB, PD, MS, MU
Kalendárium
27. 5. 2008 utorok
Príchod do kasární Dědice, ubytovanie, nafasovanie vecí, teória. Nemožné jednofarebné maskáče vzor 95, hrubé, nepoddajné, úzko strihané nohavice s vysokým pásom. Hrubá blúza - vyškovská sauna. Je ťažké vybrať si z tohto oblečenia vhodný komplet na pohyb v teréne. Ale vydržalo to všetko. Večer dve pivá vo Vojenskom klube Vyškov – Práporčíckom klube (nevydarené zahájenie). Vzhľadom na to, že nevarili a zle obsluhovali sme sa museli presídliť mimo kasárne. Začalo sa stmeľovať 2. družstvo.
28. 5. 2008 streda
Teória. 13.30 od zastávky Topol odjazd na výcvik na prekážkovej dráhe pod dohľadom vojakov z Vojenskej výcvikovej základne. Preskakovanie prekážky, beh v zákope, plazenie pod ostnatým drôtom, skok a výskok zo šachty, skákanie z naklonenej kladiny (cca 2 m), prekonávanie vodnej prekážky na tri spôsoby, plazenie sa v rúre. Pri zoskoku z kladiny došlo asi k jedinému zranenie, vyvrtnutý členok vyradil jednu účastníčku. Asi som si tam nadobudol modrinu, ktorá mi potom sčernala. Presun do kasární pešo. Velitelia nezvládli udržať tvar, dokonca ich to ani nenapadlo. Večer dve pivá v práporčíckom klube. Psycho krúžok v knižnici. P. psychologička npr. S nám okrem iného rozdala prezervatívy v armádnom balení.
29. 5. 2008 štvrtok
Skoro ráno výborná individuálna rozcvička na umelej pružnej bežeckej dráhe (4 km), vedľa prekážkovej dráhy. Krásne sa to behalo. Dobre, že som si tú rozcvičku vo Vyškove nenechal ujsť. Pobyt vo Vyškove bol takou "spomienkou na to, čo sa nakoniec nestalo"; čiže neukončil som vojenské gymnázium v r. 1986 a nenastúpil na bývalú Vysokú vojenskú školu pozemného vojska (Československej ľudovej armády) arm. gen. Ludvíka Svobodu vo Vyškove. Iba duch niektorých mojich spolužiakov sa tam ešte vznášal a ja som si predstavoval, ako by to bolo, keby som tam prišiel pred 22 rokmi. Z dráhy je nádherný výhľad na okolitú krajinu. Teória. Chemická prekážková dráha v maskách. Cestou z výcviku návšteva potravín oproti kasárňam. Večera a pivo v práporčíckom klube. Psycho krúžok v knižnici. Pivo pokračovalo za bránami kasární.
30. 5. 2008 piatok
Skoro ráno ind. rozcvička, po včerajšom pive to nebola žiadna sláva. Teória (topografia). Vojenské lezenie na konštrukcii „Jakub“. Najlepší bol traverz „francouz“.
Informácia o situácií vo fiktívnom štáte Bagram, ktorý získal samostatnosť v r. 1960. Od prelomu 16/17 st. bolo územie kolóniou. Štát má asi 5 mil obyvateľov. Hlavné mesto Mojabie leží v severovýchodnej časti štátu, na rozhraní osídlenia dvoch hlavných etnických skupín obyvateľstva. Vládnúcu skupinu tvoria väčšinoví kresťanskí Gramovia (gramotní), nespokojnú menšinu moslimskí Bastovia (bastardi). Bastovia majú ústavným článkom zaručenú autonómiu, avšak s úrovňou svojich práv a podielu na zisku z ťažby nerastov sú nespokojní. Gramovia používajú reč bagram (blízka češtine), Bastovia, aby sa odlíšili angličtinu. Štát má na území Bastov pomerne veľké nerastné bohatsto, využívajú ho však Gramovia. Politicky majú stále veľký význam kmeňoví náčelníci. Až do r. 2007 bola situácia v štáte pomerne pokojná. Voľby v r. 2007 vyhrala Demokratická strana Gramov. Bastovia reagovali na pokračujúce nerovnoprávne postavenie nelegálnou ťažbou nerastov, predaj za hranice, vytváraním oddielov domobrany a ich vyzbrojovaním. Zbrane sa pašujú cez východné hranice. V situácií keď civilná správa vrátane polície nezvládala udržať poriadok vláda uzavrela hranice a nasadila armádu. Na území Bastov je nedostatok potravín a nebezpečná situácia. V apríli 2008 BR OSN vyzvala na upokojenie situácie. V krajine sa nachádza skupina diplomatov, novinárov, humanitárnych pracovníkov (podľa vlastného výberu), ktorá sa usiluje zmapovať situáciu, poskytnúť pomoc a informovať ústredie (vlády svojich krajín a vedenie medzinárodných organizácií, redakcie médií) o situácii, možnostiach spolupráce a pomoci. Je potrebné sa pripraviť na náboženskú konfrontáciu kresťanstvo/islam zachádzajúcu do detailov ako napr. neprípustnosť konzumácie bravčového mäsa z hľadiska islamu, podozrenia zo špionáže a konfrontáciu s ľuďmi, ktorých pod vplyvom drog, alkoholu a fanatizmu nezaujímajú žiadne argumenty, ako aj dôsledné vyšetrovanie bez dodržiavania ľudských práv a prezumpcie neviny.
Večer sme sa vybrali autobusom do Vyškova (konečná) nakupovať. Vzhľadom na okolnosti „organizovaného chaosu“ a „náhlych strát“ sme nakúpené jedlo až tak nevyužili. Po kritickom prehodnotení výstroje zostalo viacej vecí (termoska, časť jedla, časť oblečenia) na internáte. Robili sme si starosti s prípravou vody na viacdňovú túru. Zbytočne. Náhradné maskáče som nechal v kasárňach. Mohol vzniknúť problém, keby chceli po prečvachtaní čaty v mokrom lese urobiť teoretické zamestnanie v "zasadačke" tábora na Ferdinandsku.
Vojenská mapa: Vojenský újezd Březina, 33 UXQ, 1 : 25 000
Civilná turistická mapa: Drahanská vrchovina 1:60 000, č. 145
31. 5. 2008 sobota
Skoro ráno posledná ind. rozcvička na bežeckej dráhe (4km). O 8.00 hod. namrdanie do vojenskej Tatry a odvoz do Zrubového tábora vedľa Ferdinandska, vojenský újezd Březina. 1 a 2 družstvo v zrube č. 4. Veliteľ kpt. P nariadil vymrdanie. Boli sme v rukách prieskumníkov. V tábore ukážky táborníctva (hamák, nosítka, kukla na raneného a pod.). Malo byť voľno do 18.00. Na 16.00 bol náhle vyhlásený nástup. Boli udané súradnice: 33 UXQ 4412 7096-cieľ, 4404 7024-prechodný bod, 4498 7080-PB. Nasledoval nácvik tichého presunu v lese, zamínovaným územím a pod. Prenos raneného na improvizovaných nosítkach. Neočakávaný nocľah v lese, vyjednávanie s domorodcami (Gramovia hovorili dobre po česky), kúpa utajenia o mieste nášho pobytu, kúpa živých moriek. Každý si mohol vybrať z batohu dve veci (minimalizácia potrebností), štvorčlenné družstvo sa teda muselo dohodnúť na skladbe 8 vecí. Ochutnali sme morčaciu krv ako možnú náhradu za nedostatkovú vodu. V ústach to nechávalo chuť podobnú tej po bitke. Pohár s krvou sa ku mne dostal keď už bol obsah zrazený a obsah chutil slizko a rôsolovito. Vyžmýkal som si tričko a okúpal sa v potoku s Michalom. Prekvapila nás pri tom barónka. Michal vyhlásil ohromnú vec: „Nedělám si iluze, že bych měl něco co jsi ješte neviděla“. Honza postavil z celty prístrešok. Morky sme zarezali (dievčatá, u nás Pavla), odrali, upiekli a zjedli. Bez oleja či masti to nebolo veľmi luxusné grilovanie. Spali sme v lese, štyria v dvoch spacákoch na striedačku. Jeden z družstva vždy udržiaval oheň. Ja som mal službu asi od 2 do 4 ale zostal som až do rána.
1. 6. 2008 nedeľa
Ráno sme už mohli použiť obsah batohov a tak som uvaril na liehovom variči čaj. Príchod do tábora. Krátka politická informácia o situácie v Bagrame. O 12.45 nástup, namrdanie do Tatry a presun na výcvik vojenského lezenia na skalách, zlaňovanie, lezenie po povrazovom rebríku, lezenie na stromy, ukážky pascí na zverinu, zdravotnícka príprava, psychologická príprava. Vysadenie na neznámom mieste a presun do tábora po družstvách. Kľúčiar Vv Robert prišiel neskoro a tak som varil na liehovom variči na chodníku. Večer sme krátko opekali špekačky. Vzhľadom na avizovaný poplach som spal v maskáčoch ale bez prilby. Poplach sa nekonal.
2. 6. 2008 pondelok
Práporčík Richard nám servíroval živých Ferdinandských mravcov v mede. Prenos borovicového samorastu na dvor ubytovne v Myslejoviciach. Miestami sme trošku bežali, hlavne ak si niekto nedal pozor na ústa. Výcvik plavby na gumových člnoch, prevoz raneného, výroba improvizovaného plavidla pre batožinu. Batoh som si na prepravu nenakladal sám a tak sa mi odmotala prilba. Našťastie neskôr som dostal inú. V tejto časti sa ma chytali myšlienky na ukončenie hry. Bolo teplo, bola tam voda a ja som sa mal hrať na vojaka a naháňať stratenú prilbu. Zaplával som si pri jej hľadaní a nijako to prešlo. Príprava a realizácia konferencie (Vv Robert a barónka) vzbúreneckého gen. domobrany Azíza (gorila, prap. Z) a plk. Harunu (prap. J) za vládnu stranu. Na záver sa pobili. Ej, ej mali sme tomu zabrániť. Správu o konferencii napísal Honza. Presun do lesa a ukážky výcviku vojenských psov, vrátane nášho navlečenia do výcvikových kombinéz. Večeru som varil na liehovom variči. Nocovanie v tábore nad priehradou. Počas noci prepad, po družstvách organizovaný presun na vopred určené zhromaždište. Pred spaním si je dobré obzrieť okolie. Pred prepadom som spal v maskáčoch, po prepade som si kvôli zime rozbalil spacák.
3. 6. 2008 utorok
Zobudil som sa skôr a raňajky som si uvaril na liehovom variči pri ohni. Do vločiek som si dal medu, aspoň raz som ho využil, tí zmrdi mi ho potom zobrali. Budíček bol naplánovaný na 6.00 hod. Konal sa o 5, 45 súbežnou paľbou zo samopalov vzor 58. Po družstvách sme sa namrdali do Tatry, odviezli nás na Kamennú chatu, dali rozpis trasy
(33 UXQ 4148 6894, 4202 6860, 4232 6972, 4230 7032, 4274 7074, 4498 7084, 4389 7146, 4527 7337, 4615 7344, 4704 7254 – cieľ (opäť chata pri Myslejovickej priehrade) a vypustili na 12 km presun po cestách s tým, že okolie je zamínované. Pavla bola na čele družstva a poriadne to hnala. Úprimne som si musel priznať, že som asi najslabší člen družstva. Pavla beháva maratón a viedla aj náš peletón. Samostatný presun 2. družstva bol výborný v tom, že sa tam málo zbytočne kecalo. Po tom, čo som si lízol soli sa môj pohyb zlepšil. Po ceste bol kontrolný bod modrých bariet, granátom zranený drevorubač s hysterickou dcérou (dala sa k rebelom), ilegálny kontrolný bod rebelov a stanovisko toho zmrda gen. domobrany Azíza. Pár desiatok metrov pred Azízom (prap. Z) nás pozastavil prap. A a zavádzajúco nám udelil ubytovacie pokyny. Ako moslim sa ten zmrd Azíz neštítil ani použitia psov proti iným (neveriacim) psom. Z predošlého dňa sme na tých havkov boli ako tak zvyknutí. Pri druhom simulovanom topení v potoku som sa priznal, že som špión. Zahrali ľudí, s ktorými nemá zmysel diskutovať. Prilba, maskáče, vreckový nôž; to všetko boli dôkazy, že sme vojaci – okupanti. Kmásali nami všeliako a všelikade. Takú páku som na ruke ešte nemal. Nôž na krk, pes na chrbte, pichľavé kamienky a drievka pod bruchom, do toho otázky či jem bravčové mäso (som vegetarián!) a príkaz niečo zaspievať. Po stiahnutí kukly som zazrel záblesk výstrelu zo striebristej pištole gen. Azíza určeného jednému z nás. V spodnej bielizni, mokrých, mierne poškriabaných a vyšľahaných žihľavou nás hnali preč uličkou medzi zdrogovanými rebelmi, ktorý nám zo samopalov vzor 58 strieľali ponad hlavy a pod nohy. Celé to trvalo 16 minút.
Dobehli sme k mobilnej zdravotnej jednotke. Inventúra vecí z prekutaných batohov (o niektoré veci sme prišli, napr. med), presun na chatu, kúpanie v priehrade, sprchovanie na ubytovni Myslejoviciach, zaliatie polievok a čaju pomocou varnej kanvice, doprial som si dôležitý dvojhodinový podvečerný spánok. Psychologický krúžok a analýza prežitého. Príprava na poplach, ktorý bol cvične vyhlásený asi tri krát. Pre istotu som sa na noc uložil v maskáčoch, topánkach a v prilbe. Azízov kontrolný bod bolo nečakané prekvapenie. O nasledujúcom prepade a rukojemníctve nás vopred informovali pomerne jasnými náznakmi, čiže mohli sa u nás už vopred dostaviť strach a obavy. Bedničky s materiálom, napr. vyšetrovacie lampy – fučíkovky boli pripravené na stole.
4. 6. 2008 streda
O 0,30 hod., krátko po vyhlásení poplachu nás rebeli prepadli pri ubytovni v Myslejoviciach, odstrelili nášho posledného ochrancu z vládnych vojakov (ostatní zmrdi zdrhli a dali sa k rebelom) a previezli na iné miesto. Po nasadení kukly sme sa stali objektom rôznych buzerácií. Prekvapujúce bolo, že rebeli používali štátny jazyk bagramštinu, čiže češtinu. Vžívam sa do vyhrážky o neprípustnosti mobilu a hodiniek a tie svoje (veľké čierne, zn. Vostok) zahadzujem. Bola aj osobná prehliadka systémom vyzliecť, prehľadať, obliecť. Nepríjemné bolo počuť medzi teroristami- rebelmi hlasy našich dovtedajších kurzových kurátorov, resp. ochrancov (prap. M „Jdem, jdem za hlasem“, prap. Richard). Na druhý deň dostávam hodinky späť a akoby zázrakom nezastavujú. Títo rebeli neboli ožratí ani zdrogovaní a počínali si pomerne systematicky. Vyskúšali sme viacero spôsobov prípravy na výsluch: plazenie sem a tam v blate, unavujúce cviky, držanie závažia vo vystretých rukách, prenášanie závažia na rôzne spôsoby, hryzúce mravce. Zničiť je možné každého. Pokiaľ sa dalo, šeptom sme sa povzbudzovali slovom "dvojka, dvojka" (druhé družstvo). Pri výsluchu ma rebel - vyšetrovateľ chytal za slová, podrypával, hľadal slabé miesta a vyzvedal na ostatných. „Co je to za zmrda ten kapitán P?“ Zistil som, že každá poskytnutá informácia sa dá zneužiť. Vecnosť výsluchu sa prelínala medzi skutočnou realitou: preverenie informácii z osobných dokladov – realitou účasti na kurze (mená dôstojníkov, dĺžka kurzu/pobytu) – a vymyslenou historkou o Bagrame. Ráno nás namrdali do Tatry a odviezli na iné miesto, kde šikana pokračovala v exteriéry, kôlňach, dierach, klietkach a pod. Tortúra skončila až o 10.00 hod slávnostnou jazdou na BVP zásahovej jednotky, ktorá nás vyslobodila. Myslel som si, že je o hodinu viac, čiže 11:00 hod. Tričko Moira s dlhými rukávmi sa vyznamenalo.
Vynárala sa otázka či sa na to nevykašlať, dať si dolu kuklu a povedať nehrám sa. Začínalo to už byť otravné (00,30 - 10,00 hod., čiže 10 hodín šikany). Volil som postup: sústredím sa na prežitok ale viem, že musia skončiť. V tejto situácii bolo na mne či chcem pokračovať alebo nie, v reáli by som musel poslúchať.
Posledné namrdanie do Tatry, odvoz do kasární, odovzdanie vecí, odhodenie potrhaných a mokrých 13 ročných vibrám do koša, očista, balenie, dve pivá v krčme naproti s Honzom a Robertom, slávnostný obed o 13.30 a postupné vytrácanie sa účastníkov v nastalom daždi. Cestou v Tatre som Michalovi z družstva venoval šprcgumu v armádnom balení, ktorú nám p. psychologička každému darovala ako všeužitočné udělátko, napr. nepremokavé puzdro na mobil.
Koniec bol veľmi rýchly. Myslím si, že 16 členovia kolektívu stmeleného prekonávaním prekážok a spoločných problémov si nestihli medzi sebou vyrozprávať všetko čo si vyrozprávať chceli. Hodilo by sa spoločné večerné posedenie v tábore pri ohni (bez nočného či ranného poplachu) alebo v krčme a odchod až ráno.
Všeobecné poznámky: Športová kondícia a napr. lezecké alebo topografické skúsenosti sa hodili. Nebola to však športová ani turistická akcia. Bol to organizovaný chaos a koncentrovaná vojenská pakáreň pri ktorej išlo skôr o precvičenie či preverenie spôsobilostí, než o výcvik. Svalovicu som rozhodne nemal a nemuseli sme sa ani naučiť všetky preberané teoretické či praktické prvky. Po povrazovom rebríku ani na stromy som sa liezť nenaučil. Úplne chýbala streľba zo zbrane, vyskúšanie nepriestrelnej vesty, výuka sebaobrany, dopravná výuka (napr. taký vojenský džíp), nácvik spojenia mobilom, vysielačkou (rozdiely medzi nimi)... a viacdňový presun. Z techniky sme v praxi zažili len korbu nákladnej Tatry, resp. V3S, čiže "vétriesky". Veľmi časté boli stretnutia so psychológmi (teoretické prednášky, testy, pohovory, rozhovory a hry, skoro na každý deň bola uložená písomná domáca úloha – postrehy a dojmy, správa o udalosti, opis ubytovacej miestnosti a pod.). Program bol dosť hustý, natiahnutý niekedy až do 20.00 hod. Ťažko povedať kedy využijem na orientáciu systém UTM a či ho dovtedy nezabudnem. Techniku GPS som ani nedržal v ruke. Učili nás pohybovať sa po lese potichu a dohovárať sa hlavne posunkami, prípadne ticho a stručne, čo naozaj zvyšuje schopnosť sledovať okolie očami, ušami, nosom aj hmatom. Naši väznitelia si medzi sebou organizačné pokyny a informácie odovzdávali slovne, čo občas kazilo atmosféru zajateckej drámy.
Teoretické prednášky
Organizácia armády Českej republiky a obrany štátu všeobecne (27. 5. 2008)
kpt. J
Ozbrojené sily ČR: AČR – cca 35 tis., Vojenská kanc. prezidenta, Hradná stráž, Záchranné roty (býv. CO), ostatné CO jednotky zmena na motorizované prápory (strata kvalifikácie členov, ktorí by sa museli navyše precvičovať na vševojskových „bigošov“).
Operačno-taktické veliteľstvá
I. Veliteľstvo spoločných síl v Olomouci.
2. (ľahká) a 7. (ťažká) Mechanizovaná brigáda existujú ako úkolové uskupenia + ostatné zložky = brigádne úkolové uskupenie (do 5000).
Pozemné sily, Vzdušné sily
II. Veliteľstvo síl podpory v Mladej Boleslavi
Krajské vojenské veliteľstvá pôsobia v administratívnych hraniciach krajov (14) a velia tzv. aktívnym zálohám (1 pešia rota) organizovaným v zmysle zák. č. 148/ Sb. AZ cvičia 21 dní v roku a pripomínajú Stráž obrany štátu z 1. ČSR. AZ sú okrem vojenských úloh určené aj na službu v záujme verejného poriadku, zvládanie živelných pohrôm a pod.
Právne predpisy: 219/1999 Z , MO ČR - § 16 zák. č. 2/1969 Sb.
Branný zákon / Sb. platí ale všeobecná branná povinnosť v mieri už nie. Občania ČR (aj ženy) schopní služby v AČR sú vojakmi v zálohe.
Mierové operácie
- medzinárodné právo, charta OSN ...
- OSN, EU, OBSE,
- peacekeeping – udržanie status quo
- peacesupport – nastolenie status quo ante
- CIMIC – spolupráca s civilným obyvateľstvom
- vojenská akcia by mala byť v čo najkratšom čase podporená politickým riešením
Pobyt a chovanie civilných osôb v ohrozených oblastiach
prap. Z
Prevencia a akcia – minimalizácia hrozieb a eliminácia rizík (minimalizácia zraniteľnosti)
Efektivita hlavnej činnosti.
Force protection
chrániť silou niekoho
seba - ROE (Rule of engement)– pravidlá zainteresovania, práva/povinnosti použitia zbrane, eskalácia odporu
SOP – operačné postupy
Stupne ohrozenia: Alpha, Bravo, Charlie, Delta
IED – improvise exploses dorses - improvizovaný výbušné zariadenie inštalované na komunikáciách, vo verejných budovách a pod., odpaľovač zameriava v teréne, môže byť hlavné a vedľajšie (pozor na pozastavenie v smrtiacej zóne)
PB – sebevražedné
VB – vozidlá (kamikadze)
CW – riadené
RC – radio/remote
VO CVD/IED – iniciované obeťou
RC/IED – vysielač prijímač
- cieľ sa musí priblížiť ale IED nemusí byť odpálené
Vojenská základňa vyžaduje organizovanosť a poriadok.
Zásady organizácie vojenských konvojov a eskort.
Zloženie skupiny: predsunutá patrola, skupina bezprostrednej ochrany, záložná a úderná skupina, konvoj musí byť ucelený. Priebehu eskorty velí veliteľ, nie VIP.
Príprava: vozidlá (lafetované zbrane), systém reakcií, komunikácia (signály), trasa a záložná trasa.
Reakcia na útok:
1. Únik. Rýchlosť je život. Opätovanie paľby len podľa plánu (ROE), činnosť jedn. častí skupiny, cez JOC sa vyžiada delostrelecká alebo letecká podpora.
2. Pokryť celú šírku cesty. Nejazdiť v línii.
3. Info o situácii na JOC.
Mínové nebezpečenstvo (28. 5. 2008)
kpt. B
Ottawa treaty 1997 – zákaz protipechotných mín, 305/1999 Sb.
- Čína, Rusko, USA mimo
- označovanie mínových polí, vyznačený priestor je bezpečný, krajnice ciest neisté
- neženijná nevybuchnutá munícia
Postup: zaregistrovať, vyhodnotiť, odchod/návrat, hlásenie
EOD ženijný tím – prehľadať, osahať, vypichať (pod 30 uhlom, 75 mm hlboko)
Protipechotné míny:
kontaktné – tlak
črepinové
šrapnelové – bowning – vyskočí
smerové (do 60 uhla horizontálne) proti ľahkým vozidlám a živej sile
Protitankové a protidopravné
protipásové
protidnové
protidopravné
Bojový zámer: strach, šok, zranenia, narušenie logistiky
Submunitions
UXO – Unexploaded ordonance
booby traps – nástrahy
Mínové nástrahy: stohovanie
Zbrane hromadného ničenia
Ing. J
- ochranné vrstvy: železo, betón, olovo
Informácia o hlavných pechotných ručných zbraniach Armády ČR (29. 5. 2008)
kpt. L
- lafetované zbrane: upevnené v palebnej pozícií, napr. na vozidlo
Vojenské operácie – misie (29. 5. 2008)
kpt. S
Hostage management
- privilégiá a imunity a ich rešpektovanie
- dôvod únosu: ideovo – politický, komerčný – výkupné (medz. org. neplatia)
- únoscovia: vojaci teroristi, kriminálnici, psychopati
- profesionálne vyjednávanie
- informovanie/varovanie: pan pan pan, mayday, hijack, SOP má obsahovať aj rozdelenie kanálov,
- žiadna panika, útočník je naštartovaný, nervózny, treba ho poslúchať, rešpektovať ich pravidlá (pri nerovnosti síl a šancí), pozorovať a plánovať útek,
- snažiť sa pochopiť ich záujmy,
- zachraňovať len život, preveriť spoluväzňov,
- sebakontrola: logika, priority, myšlienková aktivita, telesná aktivita, primeraná sústredenosť.
Psychológia prežitia
- dôležitá je aktivita a vôľa
- BIO – jesť, aj keď je to nechutné, cvičiť
- psycho (rozum+emócie+vôľa) – udržanie si vlastného sveta, poriadku, dôstojnosti, sústredenia
- socio – kontakt s únoscami, spoluväzňami; vedúci skupiny, (aspoň zdanlivo) zmysluplné úlohy pre všetkých členov, spoločná informovanosť a plány, skupina je tak silná, ako je silný jej najslabší člen
- rozum: zhodnocuje situáciu, objektivizuje intuíciu, vôľa: núti niečo robiť, nezmyselne sa opakujúce činnosti sú prejavom úpadku vôle, emócie: nabúdzajú vedomie a vnímanie, môžu napr. čiastočne nahrádzať zmysly (?), sluch + emócie = intuitívne hodnotenie človeka bez použitia zraku.
Je nevyhnutné prijať vnútenú rolu zajatca/rukojemníka. Najväčším hrdinstvom je úspešný útek. Pre prípad zásahu osloboditeľov je dobré sedieť v strede miestnosti s hlavou medzi kolenami, pri zásahu sa znehybniť na zemi, resp. vzdať sa, dať sa bezproblémovo zatknúť a vysvetľovať až bude na to vhodný čas.
- reakcia na stres: A. – začervenanie, aktívna bojová príprava
B. – zblednutie, pasivita, stuhlosť
- po akcii je nevyhnutné stres vyfiltrovať
- význam a zraniteľnosť jednotlivých zmyslov:
zrak: najľahšie sa obmedzuje (kukla), z hľadiska väzniteľov je najnebezpečnejší
čuch: oživuje a spúšťa aj dávno zabudnuté podnety, zápach odrádza útočníka a tým chráni ohrozeného (len to musí vydržať)
chuť: je zradná pri potrebe živiť sa netradičnou potravou (neznáme jedlá, surová krv zvierat, korienky atď)
hmat: má receptory po celom tele, vníma hmotné aj nehmotné veci (teplota, vietor, slnko atď), jeho význam sa zvyšuje obmedzením zraku:
Stupne pozornosti
1. Nepozornosť – môžeme si ju dovoliť v známom prostredí a stave bezpečia
2. Pozornosť.
3. Pripravenosť – analyzujem svoje postavenie.
4. Akcia – dôležité je prelomenie prekvapenia, rozhodnutie, vydanie prvého povelu atď
5. Šok – chaos, zmätok, neovládnutie situácie. Môže byť dôsledkom aj uvedomia si skutočného rozsahu katastrofy, nehody či útoku.
Konflikty s únoscami, medzi rukojemníkmi a ich zvládanie
Predstavy a ich konkretizácia
Názory a protiargumenty
Postoje sú emotívne
Záujmy sú limitujúce
Kompromis neobsahuje prvok, ktorý by bol pre niektorého účastníka neprijateľný
Útek je najefektívnejší na začiatku, napr. hneď pri prepade. Rukojemníci ešte nie sú spočítaní a únoscovia sa snažia opustiť rýchlo priestor. Na druhej strane sú nadržaný, nervózny, príp. zúriví. 2 hodiny trvajúci útek neznámym smerom/cca 10 km na dĺžku = maximálne až 400 km2, reálne menej. Možnosti utečenca vymädzuje aj štruktúra územia, cesty, mosty, vodné toky atď. Pes vycíti blízkosť prenasledovaného 10 – 15 min. vopred.
Pri úteku je možné sa maskovať (ale celistvo, vrátane doplnkov), pozor na psy a deti.
Pred vojskom je možné sa zaryť a nechať sa prekročiť.
Informatika prežitia
Xeroxované doklady, scan dokladov uložený na sieti internet
Fyzika a chémia prežitia
Dezinfekcia ovocia manganistanom draselným, vody tiež MD alebo jódom, savom, chlórom, 15 min. varom, príp. v tlakovom hrnci. Pri nedostatku vody nefajčiť a kontrolovať stravu. Za deň je možné vypiť 6 – 8 dúškov morskej vody. Destilovať vodu z vlhkej jamy, filtrovať cez piesok, popol, žuvadlo pod jazyk, piť miazgu stromov, koreňov, krv zvierat. V plastovej fľaši v ohni sa voda uvarí. Had by mal byť jedlý po odseknutí dvojnásobku dĺžky hlavy. Prezervatív je univerzálny: v ponožke bandaska na vodu, sterilná rukavica, ochrana na elektroniku pred vodou atď
Vybudovať vrstvený prístrešok. Zem je horúca/studená – minimalizovať plochu dotyku.
24 hodín bez spánku navodzuje stav na spôsob ľahkej opitosti.
Vyškovský výcvik:
http://zpravy.idnes.cz/serial-o-vojenskem-vycviku-ddw-/zpr_nato.aspx?c=A160803_071828_zpr_nato_inc
http://zpravy.idnes.cz/serial-o-vojenskem-vycviku-druhy-dqq-/zpr_nato.aspx?c=A160809_104926_zpr_nato_inc
http://zpravy.idnes.cz/vojensky-vycvik-ocima-dobrovolnika-dbl-/zpr_nato.aspx?c=A160816_115226_zpr_nato_inc
http://zpravy.idnes.cz/vojensky-vycvik-ocima-dobrovolnika-ctyri-fij-/zpr_nato.aspx?c=A160824_085552_zpr_nato_inc
Topografia (30. 5. 2008)
pprap. H
UTM systém
The Universal Transverse Mercator (UTM) coordinate system is a grid-based method of specifying locations on the surface of the Earth. It is used to identify locations on the earth, but differs from the traditional method of latitude and longitude in several respects.
The UTM system is not a single map projection. The system instead employs a series of sixty zones, each of which is based on a specifically defined secant Transverse Mercator projection.
The UTM Grid
|
Contents
[hide]
|
[edit] History
The Universal Transverse Mercator coordinate system was developed by the United States Army Corps of Engineers in the 1940s.[1] The system was based on an ellipsoidal model of the Earth. For areas within the conterminous United States, the Clarke 1866 ellipsoid was used. For the remaining areas of the Earth, including Hawaii, the International Ellipsoid was used. Currently, the WGS84 ellipsoid is used as the underlying model of the Earth in the UTM coordinate system.
Prior to the development of the Universal Transverse Mercator coordinate system, several European nations demonstrated the utility of grid-based conformal maps by mapping their territory during the interwar period. Calculating the distance between two points on these maps could be performed more easily in the field (using the Pythagorean theorem) than was otherwise possible using the trigonometric formulas required under the graticule-based system of latitude and longitude. In the post-war years, these concepts were extended into the Universal Transverse Mercator / Universal Polar Stereographic (UTM/UPS) coordinate system, which is a global (or Universal) system of grid-based maps.
The Transverse Mercator Projection is a variant of the Mercator Projection, which was originally developed by the Flemish geographer and cartographer Gerardus Mercator, in 1569.
It should be carefully noted that the projection defined by the projection of the Earth onto a cylinder is not conformal, and Mercator projections are invariably non-linearly scaled to provide this property. UTM involves non-linear scaling in both Eastings and Northings to ensure the projected map of the ellipsoid is conformal.
[edit] Definitions
[edit] UTM longitude zone
Simplified view of US UTM longitude zones.
The UTM system divides the surface of the Earth between 80° S latitude and 84° N latitude into 60 zones, each 6° of longitude in width and centered over a meridian of longitude. Zones are numbered from 1 to 60. Zone 1 is bounded by longitude 180° to 174° W and is centered on the 177th West meridian. Zone numbering increases in an easterly direction.
Each of the 60 longitude zones in the UTM system is based on a Transverse Mercator projection, which is capable of mapping a region of large north-south extent with a low amount of distortion. By using narrow zones of 6° (to 800km resp.) in width, and reducing the scale factor along the central meridian by only 0.0004 (to 0.9996, a reduction of 1:2500) the amount of distortion is held below 1 part in 1,000 inside each zone. Distortion of scale increases to 1.0010 at the outer zone boundaries along the equator.
The secant projection in each zone creates two standard lines, or lines of true scale, located approximately 180 km on either side of, and approximately parallel to, the central meridian. The scale factor is less than 1 inside these lines and greater than 1 outside of these lines, but the overall distortion of scale inside the entire zone is minimized.
[edit] UTM latitude zone
The UTM system segments each longitude zone into 20 latitude zones. Each latitude zone is 8 degrees high, and is lettered starting from "C" at 80° S, increasing up the English alphabet until "X", omitting the letters "I" and "O" (because of their similarity to the digits one and zero). The last latitude zone, "X", is extended an extra 4 degrees, so it ends at 84° N latitude, thus covering the northern most land on Earth. Latitude zones "A" and "B" do exist, as do zones "Y" and Z". They cover the western and eastern sides of the Antarctic and Arctic regions respectively. A convenient trick to remember is that the letter "N" is the first letter in the northern hemisphere, so any letter coming before "N" in the alphabet is in the southern hemisphere, and any letter "N" or after is in the northern hemisphere.
[edit] Notation
Each grid square is referred to by the longitude zone number and the latitude zone character. The longitude zone is always written first, followed by the latitude zone. For example (see image, top right), a position in Toronto, Canada, would find itself in longitude zone 17 and latitude zone "T", thus the full reference is "17T".
[edit] Exceptions
These longitude and latitude zones are uniform over the globe, except in two areas. On the southwest coast of Norway, the UTM zone 32V is extended further west, and the zone 31V is correspondingly shrunk to cover only open water. Also, in the region around Svalbard, the four zones 31X, 33X, 35X, and 37X are extended to cover what would otherwise have been covered by the seven zones 31X to 37X. The three zones 32X, 34X and 36X are not used.
|
Europe
|
Africa
|
South America
|
Bering Sea with Alaska
|
Picture gallery: UTM zones in various parts of the world
[edit] Locating a position using UTM coordinates
A position on the Earth is referenced in the UTM system by the UTM longitude zone, and the easting and northing coordinate pair. The easting is the projected distance of the position from the central meridian, while the northing is the projected distance of the point from the equator. The point of origin of each UTM zone is the intersection of the equator and the zone's central meridian. In order to avoid dealing with negative numbers, the central meridian of each zone is given a "false easting" value of 500,000 meters. Thus, anything west of the central meridian will have an easting less than 500,000 meters. For example, UTM eastings range from 167,000 meters to 833,000 meters at the equator (these ranges narrow towards the poles). In the northern hemisphere, positions are measured northward from the equator, which has an initial "northing" value of 0 meters and a maximum "northing" value of approximately 9,328,000 meters at the 84th parallel — the maximum northern extent of the UTM zones. In the southern hemisphere, northings decrease as you go southward from the equator, which is given a "false northing" of 10,000,000 meters so that no point within the zone has a negative northing value.
As an example, the CN Tower is located at the geographic position 43°38′33.24″N, 79°23′13.7″W. This is in longitude zone 17, and the grid position is 630084m east, 4833438m north.
The latitude zone is unnecessary if the full distance from the equator is given (as above) and the hemisphere is known. It does, however, become important when further sub-division of the UTM grid is undertaken, such as in the military grid reference system.
[edit] Overlapping Grids
Distortion of scale increases in each UTM zone as the boundaries between the longitude zones are approached. However, it is often convenient or necessary to measure a series of locations on a single grid when some are located in two adjacent zones. Around the boundaries of large scale maps (1:100,000 or larger) coordinates for both adjoining UTM zones are usually printed within a minimum distance of 40 km on either side of a zone boundary. Ideally, the coordinates of each position should be measured on the grid for the zone in which they are located, but because the scale factor is still relatively small near zone boundaries, it is possible to overlap measurements into an adjoining zone for some distance when necessary.
But this overlap of grids is intended only to simplify measurements on a map. When the position of a point should be expressed in UTM coordinates, one must use the grid of the zone that contains the point.
MGRS systém
Military grid reference system
From Wikipedia, the free encyclopedia
Jump to: navigation, search
The Military Grid Reference System (MGRS)[1] is the geocoordinate standard used by NATO militaries for locating points on the earth. In most areas (between latitudes 80°S and 84°N), the MGRS grid is identical to the UTM (Universal Transverse Mercator) grid system, but uses a different labeling convention. In the polar regions, MGRS is based on the Universal Polar Stereographic system.
An example of an MGRS coordinate, or grid reference, would be 4QFJ12345678, which consists of three parts:
- 4Q (the grid zone),
- FJ (the 100,000-meter square), and
- 12345678 (numerical location; easting is 1234 and northing is 5678, in this case specifying a location within a 10m square).
It is important to note that an MGRS grid reference does not describe a point on the earth's surface, but rather a square area of 10km x 10km, 1km x 1km, 100m x 100m, 10m x 10m or 1m x 1m, depending on the precision of the coordinates provided. The total number of digits must be 2, 4, 6, 8 or 10, respectively, depending on the desired resolution. All points within that square will have the same coordinates.
Such an MGRS coordinate, standing alone, may be converted to latitude and longitude. But you still do not know the position on the Earth, unless you also know the geodetic datum that is used.
|
Contents
[hide]
|
[edit] Grid zone designation
The first part of an MGRS coordinate is the grid-zone designation. The 6° wide UTM zones, numbered 1 - 60, are intersected by latitude bands that are normally 8° high, lettered C - X (omitting I and O). The northmost latitude band, X, is 12° high. The intersection of a UTM zone and a latitude band is (normally) a 6° * 8° rectangle called a grid zone, whose designation in MGRS is formed by the zone number and the latitude band letter. The same notation is often used in UTM; the article on Universal Transverse Mercator shows many maps of these grid zones, including the irregularities for Svalbard and southwest Norway. In the map here (figure 1), you can see that Honolulu is in grid zone 4Q.
Figure 1. The origin of the MGRS grid, in the Pacific. You can see Honolulu in 4QFJ.
[edit] 100,000-meter square identification
The second part of an MGRS coordinate is the 100,000-meter square identification. Each UTM zone is divided into 100,000 meter squares, so that their corners have UTM-coordinates that are multiples of 100,000 meters. The identification consists of a column letter (A - Z, omitting I and O) followed by a row letter (A - V, omitting I and O).
Near the equator, the columns of UTM zone 1 have the letters A - H, the columns of UTM zone 2 have the letters J - R (omitting O), and the columns of UTM zone 3 have the letters S - Z. At zone 4, the column letters start over from A, and so on around the world.
For the row letters, there are actually two alternative lettering schemes within MGRS:
- In the AA scheme,[2] also known as MGRS-New,[3] which is used for WGS84 and some other modern geodetic datums, the letter for the first row - just north of the equator - is A in odd-numbered zones, and F in even-numbered zones, as shown in figure 1. Note that the westmost square in this row, in zone 1, has identification AA.
- In the alternative AL scheme,[2] also known as MGRS-Old,[3] which is used for some older geodetic datums, the row letters are shifted 10 steps in the alphabet. This means that the letter for the first row is L in odd-numbered zones and R in even-numbered zones. The westmost square in the first row, in zone 1, has identification AL.
If an MGRS coordinate is complete (with both a grid zone designation and a 100,000 meter square identification), and is valid in one lettering scheme, then it is usually invalid in the other scheme, which will have no such 100,000 meter square in the grid zone. (Latitude band X is the exception to this rule.) Therefore, a position reported in a modern datum usually can not be misunderstood as using an old datum, and vice versa - provided the datums use different MGRS lettering schemes.
In the map (figure 1), which uses the AA scheme, we see that Honolulu is in grid zone 4Q, and square FJ. To give the position of Honolulu with 100 km resolution, we write 4QFJ.
Figure 2. The MGRS grid around Hawaii. You can see Honolulu in 4QFJ15.
[edit] Numerical location
The third part of an MGRS coordinate is the numerical location within a 100,000 meter square, given as n+n digits, where n is 1, 2, 3, 4, or 5. If 5 + 5 digits is used, the first 5 digits give the easting in meters, measured from the left edge of the square, and the last 5 digits give the northing in meters, measured from the bottom edge of the square. The resolution in this case is 1 meter, so the MGRS coordinate would represent a 1 meter square, where the easting and northing are measured to its southwest corner. If a resolution of 10 meters is enough, the final digit of the easting and northing can be dropped, so that only 4 + 4 digits are used, representing a 10 meter square. If a 100 meter resolution is enough, 3 + 3 digits suffice; if a 1 km resolution is enough, 2 + 2 digits suffice; if 10 km resolution is enough, 1 + 1 digits suffice. 10 meter resolution (4 + 4 digits) is sufficient for many purposes, and is the NATO standard for specifying coordinates.
If we zoom in on Hawaii (figure 2), we see that the position of Honolulu, with 10 km resolution, would be written 4QFJ15.
If the grid zone or 100,000-meter square are clear from context, they can be dropped, and only the numerical location is specified. For example:
- If every position being located is within the same grid zone, only the 100,000-meter square and numerical location are specified.
- If every position being located is within the same grid zone and 100,000-meter square, only the numerical location is specified.
- However, even if every position being located is within a small area, but the area overlaps multiple 100,000-meter squares or grid zones, the entire grid reference is required.
One always reads map coordinates from West to East first (Easting), then from South to North (Northing). (Common mnemonics include "In the house, up the stairs," and "Left-to-right, bottom-to-top.")
[edit] Polar regions
Figure 3. The MGRS grid around the South Pole.
Figure 4. The MGRS grid around the North Pole.
In the polar regions, a different convention is used.[4] South of 80°S, UPS South (Universal Polar Stereographic) is used instead of a UTM projection. The west half-circle forms a grid zone with designation A; the east half-circle forms one with designation B; see figure 3. North of 84°N, UPS North is used, and the west half-circle is Y, the east one is Z; see figure 4. Since the letters A, B, Y, and Z are not used for any latitude bands of UTM, their presence in an MGRS coordinate, with the omission of a zone number, indicates that the coordinates are in the UPS system.
The lettering scheme for 100,000 km squares is slightly different in the polar regions. The row letters go from A to Z, omitting I and O. The column letters use a more restricted alphabet, going from A to Z but omitting I, O, D, E, M, N, V, W; the columns are arranged so that the rightmost column in grid zone A and Y has column letter Z, and the next column in grid zone B or Z starts over with column letter A. The restricted column alphabet for UPS ensures that no UPS square will be adjacent to a UTM square with the same identification.
In the polar regions, there is only one version of the lettering scheme.[4]
[edit] References
GPS
Global Positioning System
From Wikipedia, the free encyclopedia
(Redirected from GPS)
Jump to: navigation, search
"GPS" redirects here. For other similar systems, see Global Navigation Satellite System. For other uses of GPS, see GPS (disambiguation).
|
Artist's conception of GPS satellite in orbit
|
|
Civilian GPS receiver in a marine application.
|
The Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 Medium Earth Orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its location, speed, direction, and time. Other similar systems are the Russian GLONASS (incomplete as of 2008), the upcoming European Galileo positioning system, the proposed COMPASS navigation system of China, and IRNSS of India.
Developed by the United States Department of Defense, GPS is officially named NAVSTAR GPS (Contrary to popular belief, NAVSTAR is not an acronym, but simply a name given by John Walsh, a key decision maker when it came to the budget for the GPS program).[1] The satellite constellation is managed by the United States Air Force 50th Space Wing. The cost of maintaining the system is approximately US$750 million per year,[2] including the replacement of aging satellites, and research and development.
Following the shooting down of Korean Air Lines Flight 007 in 1983, President Ronald Reagan issued a directive making the system available for free for civilian use as a common good.[3] Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, and hobbies such as geocaching. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.
|
Contents
[hide]
|
[edit] Simplified method of operation
A typical GPS receiver calculates its position using the signals from four or more GPS satellites. Four satellites are needed since the process needs a very accurate local time, more accurate than any normal clock can provide, so the receiver internally solves for time as well as position. In other words, the receiver uses four measurements to solve for four variables: x, y, z, and t. These values are then turned into more user-friendly forms, such as latitude/longitude or location on a map, then displayed to the user.
Each GPS satellite has an atomic clock, and continually transmits messages containing the current time at the start of the message, parameters to calculate the location of the satellite (the ephemeris), and the general system health (the almanac). The signals travel at the speed of light through outer space, and slightly slower through the atmosphere. The receiver uses the arrival time to compute the distance to each satellite, from which it determines the position of the receiver using geometry and trigonometry (see trilateration[4])
Although four satellites are required for normal operation, fewer may be needed in some special cases. If one variable is already known (for example, a sea-going ship knows its altitude is 0), a receiver can determine its position using only three satellites. Also, in practice, receivers use additional clues (doppler shift of satellite signals, last known position, dead reckoning, inertial navigation, and so on) to give degraded answers when fewer than four satellites are visible.
[edit] Technical description
Unlaunched GPS satellite on display at the San Diego Aerospace museum
[edit] System segmentation
The current GPS consists of three major segments. These are the space segment (SS), a control segment (CS), and a user segment (US).[5]
[edit] Space segment
See also: GPS satellite and List of GPS satellite launches
A visual example of the GPS constellation in motion with the Earth rotating. Notice how the number of satellites in view from a given point on the Earth's surface, in this example at 45°N, changes with time.
The space segment (SS) comprises the orbiting GPS satellites, or Space Vehicles (SV) in GPS parlance. The GPS design originally called for 24 SVs, eight each in three circular orbital planes,[6] but this was modified to six planes with four satellites each.[7] The orbital planes are centered on the Earth, not rotating with respect to the distant stars.[8] The six planes have approximately 55° inclination (tilt relative to Earth's equator) and are separated by 60° right ascension of the ascending node (angle along the equator from a reference point to the orbit's intersection).[2] The orbits are arranged so that at least six satellites are always within line of sight from almost everywhere on Earth's surface.[9]
Orbiting at an altitude of approximately 20,200 kilometers (12,600 miles or 10,900 nautical miles; orbital radius of 26,600 km (16,500 mi or 14,400 NM)), each SV makes two complete orbits each sidereal day.[10] The ground track of each satellite therefore repeats each (sidereal) day. This was very helpful during development, since even with just four satellites, correct alignment means all four are visible from one spot for a few hours each day. For military operations, the ground track repeat can be used to ensure good coverage in combat zones.
As of September 2007, there are 31 actively broadcasting satellites in the GPS constellation. The additional satellites improve the precision of GPS receiver calculations by providing redundant measurements. With the increased number of satellites, the constellation was changed to a nonuniform arrangement. Such an arrangement was shown to improve reliability and availability of the system, relative to a uniform system, when multiple satellites fail.[11]
[edit] Control segment
The flight paths of the satellites are tracked by US Air Force monitoring stations in Hawaii, Kwajalein, Ascension Island, Diego Garcia, and Colorado Springs, Colorado, along with monitor stations operated by the National Geospatial-Intelligence Agency (NGA).[12] The tracking information is sent to the Air Force Space Command's master control station at Schriever Air Force Base in Colorado Springs, which is operated by the 2nd Space Operations Squadron (2 SOPS) of the United States Air Force (USAF). Then 2 SOPS contacts each GPS satellite regularly with a navigational update (using the ground antennas at Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs). These updates synchronize the atomic clocks on board the satellites to within a few nanoseconds of each other, and adjust the ephemeris of each satellite's internal orbital model. The updates are created by a Kalman filter which uses inputs from the ground monitoring stations, space weather information, and various other inputs.[13]
Satellite maneuvers are not precise by GPS standards. So to change the orbit of a satellite, the satellite must be marked 'unhealthy', so receivers will not use it in their calculation. Then the maneuver can be carried out, and the resulting orbit tracked from the ground. Then the new ephemeris is uploaded and the satellite marked healthy again.
[edit] User segment
GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such as those shown here from manufacturers Trimble, Garmin and Leica (left to right).
The user's GPS receiver is the user segment (US) of the GPS. In general, GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly-stable clock (often a crystal oscillator). They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously. Originally limited to four or five, this has progressively increased over the years so that, as of 2007, receivers typically have between 12 and 20 channels.[14]
A typical OEM GPS receiver module, based on the SiRF Star III chipset, measuring 15×17 mm, and used in many products.
GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of a RS-232 port at 4,800 bit/s speed. Data is actually sent at a much lower rate, which limits the accuracy of the signal sent using RTCM. Receivers with internal DGPS receivers can outperform those using external RTCM data. As of 2006, even low-cost units commonly include Wide Area Augmentation System (WAAS) receivers.
SiRFstar III receiver and integrated antenna from UK company Antenova. This measures just 49 x 9 x 4 mm.
Many GPS receivers can relay position data to a PC or other device using the NMEA 0183 protocol. NMEA 2000[15] is a newer and less widely adopted protocol. Both are proprietary and controlled by the US-based National Marine Electronics Association. References to the NMEA protocols have been compiled from public records, allowing open source tools like gpsd to read the protocol without violating intellectual property laws. Other proprietary protocols exist as well, such as the SiRF and MTK protocols. Receivers can interface with other devices using methods including a serial connection, USB or Bluetooth.
[edit] Navigation signals
GPS broadcast signal
Each GPS satellite continuously broadcasts a Navigation Message at 50 bit/s giving the time-of-week, GPS week number and satellite health information (all transmitted in the first part of the message), an ephemeris (transmitted in the second part of the message) and an almanac (later part of the message). The messages are sent in frames, each taking 30 seconds to transmit 1500 bits.
The first 6 seconds of every frame contains data describing the satellite clock and its relationship to GPS time. The next 12 seconds contain the ephemeris data, giving the satellite's own precise orbit. The ephemeris is updated every 2 hours and is generally valid for 4 hours, with provisions for updates every 6 hours or longer in non-nominal conditions. The time needed to acquire the ephemeris is becoming a significant element of the delay to first position fix, because, as the hardware becomes more capable, the time to lock onto the satellite signals shrinks, but the ephemeris data requires 30 seconds (worst case) before it is received, due to the low data transmission rate.
The almanac consists of coarse orbit and status information for each satellite in the constellation, an ionospheric model, and information to relate GPS derived time to Coordinated Universal Time (UTC). A new part of the almanac is received for the last 12 seconds in each 30 second frame. Each frame contains 1/25th of the almanac, so 12.5 minutes are required to receive the entire almanac from a single satellite[16]. The almanac serves several purposes. The first is to assist in the acquisition of satellites at power-up by allowing the receiver to generate a list of visible satellites based on stored position and time, while an ephemeris from each satellite is needed to compute position fixes using that satellite. In older hardware, lack of an almanac in a new receiver would cause long delays before providing a valid position, because the search for each satellite was a slow process. Advances in hardware have made the acquisition process much faster, so not having an almanac is no longer an issue. The second purpose is for relating time derived from the GPS (called GPS time) to the international time standard of UTC. Finally, the almanac allows a single frequency receiver to correct for ionospheric error by using a global ionospheric model. The corrections are not as accurate as augmentation systems like WAAS or dual frequency receivers. However it is often better than no correction since ionospheric error is the largest error source for a single frequency GPS receiver. An important thing to note about navigation data is that each satellite transmits only its own ephemeris, but transmits an almanac for all satellites.
Each satellite transmits its navigation message with at least two distinct spread spectrum codes: the Coarse / Acquisition (C/A) code, which is freely available to the public, and the Precise (P) code, which is usually encrypted and reserved for military applications. The C/A code is a 1,023 chip pseudo-random (PRN) code at 1.023 million chips per second so that it repeats every millisecond. Each satellite has its own C/A code so that it can be uniquely identified and received separately from the other satellites transmitting on the same frequency. The P-code is a 10.23 megachip per second PRN code that repeats only every week. When the "anti-spoofing" mode is on, as it is in normal operation, the P code is encrypted by the Y-code to produce the P(Y) code, which can only be decrypted by units with a valid decryption key. Both the C/A and P(Y) codes impart the precise time-of-day to the user.
Frequencies used by GPS include
- L1 (1575.42 MHz): Mix of Navigation Message, coarse-acquisition (C/A) code and encrypted precision P(Y) code, plus the new L1C on future Block III satellites.
- L2 (1227.60 MHz): P(Y) code, plus the new L2C code on the Block IIR-M and newer satellites.
- L3 (1381.05 MHz): Used by the Nuclear Detonation (NUDET) Detection System Payload (NDS) to signal detection of nuclear detonations and other high-energy infrared events. Used to enforce nuclear test ban treaties.
- L4 (1379.913 MHz): Being studied for additional ionospheric correction.
- L5 (1176.45 MHz): Proposed for use as a civilian safety-of-life (SoL) signal (see GPS modernization). This frequency falls into an internationally protected range for aeronautical navigation, promising little or no interference under all circumstances. The first Block IIF satellite that would provide this signal is set to be launched in 2009[17].
[edit] Calculating positions
[edit] Using the C/A code
To start off, the receiver picks which C/A codes to listen for by PRN number, based on the almanac information it has previously acquired. As it detects each satellite's signal, it identifies it by its distinct C/A code pattern, then measures the received time for each satellite. To do this, the receiver produces an identical C/A sequence using the same seed number, referenced to its local clock, starting at the same time the satellite sent it. It then computes the offset to the local clock that generates the maximum correlation. This offset is the time delay from the satellite to the receiver, as told by the receiver's clock. Since the PRN repeats every millisecond, this offset is precise but ambiguous, and the ambiguity is resolved by looking at the data bits, which are sent at 50 Hz (20 ms) and aligned with the PRN code.
This data is used to solve for x,y,z and t. Many mathematical techniques can be used. The following description shows a straightforward iterative way, but receivers use more sophisticated methods. (see below)
Conceptually, the receiver calculates the distance to the satellite, called the pseudorange[18].
Overlapping pseudoranges, represented as curves, are modified to yield the probable position
Next, the orbital position data, or ephemeris, from the Navigation Message is then downloaded to calculate the satellite's precise position. A more-sensitive receiver will potentially acquire the ephemeris data more quickly than a less-sensitive receiver, especially in a noisy environment.[19] Knowing the position and the distance of a satellite indicates that the receiver is located somewhere on the surface of an imaginary sphere centered on that satellite and whose radius is the distance to it. Receivers can substitute altitude for one satellite, which the GPS receiver translates to a pseudorange measured from the center of the Earth.
When pseudoranges have been determined for four satellites, a guess of the receiver's location is calculated. Dividing the speed of light by the distance adjustment required to make the pseudoranges come as close as possible to intersecting results in a guess of the difference between UTC and the time indicated by the receiver's on-board clock. With each combination of four satellites, a geometric dilution of precision (GDOP) vector is calculated, based on the relative sky positions of the satellites used. As more satellites are picked up, pseudoranges from more combinations of four satellites can be processed to add more guesses to the location and clock offset. The receiver then determines which combinations to use and how to calculate the estimated position by determining the weighted average of these positions and clock offsets. After the final location and time are calculated, the location is expressed in a specific coordinate system, e.g. latitude/longitude, using the WGS 84 geodetic datum or a local system specific to a country.
There are many other alternatives and improvements to this process. If at least four satellites are visible, for example, the receiver can eliminate time from the equations by computing only time differences, then solving for position as the intersection of hyperboloids. Also, with a full constellation and modern receivers, more than four satellites can be seen and received at once. Then all satellite data can be weighted by GDOP, signal to noise, path length through the ionosphere, and other accuracy concerns, and then used in a least squares fit to find a solution. In this case the residuals also give an estimate of the errors. Finally, results from other positioning systems such as GLONASS or the upcoming Galileo can be used in the fit, or used to double-check the result. (By design, these systems use the same bands, so much of the receiver circuitry can be shared, though the decoding is different).
[edit] Using the P(Y) code
Calculating a position with the P(Y) signal is generally similar in concept, assuming one can decrypt it. The encryption is essentially a safety mechanism: if a signal can be successfully decrypted, it is reasonable to assume it is a real signal being sent by a GPS satellite.[citation needed] In comparison, civil receivers are highly vulnerable to spoofing since correctly formatted C/A signals can be generated using readily available signal generators. RAIM features do not protect against spoofing, since RAIM only checks the signals from a navigational perspective.
[edit] Accuracy and error sources
|
Sources of User Equivalent Range Errors (UERE)
|
|
|
Source
|
Effect
|
|
Ionospheric effects
|
± 5 meter
|
|
Ephemeris errors
|
± 2.5 meter
|
|
Satellite clock errors
|
± 2 meter
|
|
Multipath distortion
|
± 1 meter
|
|
Tropospheric effects
|
± 0.5 meter
|
|
Numerical errors
|
± 1 meter
|
The position calculated by a GPS receiver requires the current time, the position of the satellite and the measured delay of the received signal. The position accuracy is primarily dependent on the satellite position and signal delay.
To measure the delay, the receiver compares the bit sequence received from the satellite with an internally generated version. By comparing the rising and trailing edges of the bit transitions, modern electronics can measure signal offset to within about 1% of a bit time, or approximately 10 nanoseconds for the C/A code. Since GPS signals propagate at the speed of light, this represents an error of about 3 meters.
Position accuracy can be improved by using the higher-chiprate P(Y) signal. Assuming the same 1% bit time accuracy, the high frequency P(Y) signal results in an accuracy of about 30 centimeters.
Electronics errors are one of several accuracy-degrading effects outlined in the table below. When taken together, autonomous civilian GPS horizontal position fixes are typically accurate to about 15 meters (50 ft). These effects also reduce the more precise P(Y) code's accuracy.
[edit] Atmospheric effects
Inconsistencies of atmospheric conditions affect the speed of the GPS signals as they pass through the Earth's atmosphere, especially the ionosphere. Correcting these errors is a significant challenge to improving GPS position accuracy. These effects are smallest when the satellite is directly overhead and become greater for satellites nearer the horizon since the path through the atmosphere is longer (see airmass). Once the receiver's approximate location is known, a mathematical model can be used to estimate and compensate for these errors.
Because ionospheric delay affects the speed of microwave signals differently depending on their frequency — a characteristic known as dispersion - delays measured on two more frequency bands can be used to measure dispersion, and this measurement can then be used to estimate the delay at each frequency[20]. Some military and expensive survey-grade civilian receivers measure the different delays in the L1 and L2 frequencies to measure atmospheric dispersion, and apply a more precise correction. This can be done in civilian receivers without decrypting the P(Y) signal carried on L2, by tracking the carrier wave instead of the modulated code. To facilitate this on lower cost receivers, a new civilian code signal on L2, called L2C, was added to the Block IIR-M satellites, which was first launched in 2005. It allows a direct comparison of the L1 and L2 signals using the coded signal instead of the carrier wave.
The effects of the ionosphere generally change slowly, and can be averaged over time. The effects for any particular geographical area can be easily calculated by comparing the GPS-measured position to a known surveyed location. This correction is also valid for other receivers in the same general location. Several systems send this information over radio or other links to allow L1-only receivers to make ionospheric corrections. The ionospheric data are transmitted via satellite in Satellite Based Augmentation Systems such as WAAS, which transmits it on the GPS frequency using a special pseudo-random noise sequence (PRN), so only one receiver and antenna are required.
Humidity also causes a variable delay, resulting in errors similar to ionospheric delay, but occurring in the troposphere. This effect both is more localized and changes more quickly than ionospheric effects, and is not frequency dependent. These traits make precise measurement and compensation of humidity errors more difficult than ionospheric effects.
Changes in receiver altitude also change the amount of delay, due to the signal passing through less of the atmosphere at higher elevations. Since the GPS receiver computes its approximate altitude, this error is relatively simple to correct, either by applying a function regression or correlating margin of atmospheric error to ambient pressure using a barometric altimeter.
[edit] Multipath effects
GPS signals can also be affected by multipath issues, where the radio signals reflect off surrounding terrain; buildings, canyon walls, hard ground, etc. These delayed signals can cause inaccuracy. A variety of techniques, most notably narrow correlator spacing, have been developed to mitigate multipath errors. For long delay multipath, the receiver itself can recognize the wayward signal and discard it. To address shorter delay multipath from the signal reflecting off the ground, specialized antennas (e.g. a choke ring antenna) may be used to reduce the signal power as received by the antenna. Short delay reflections are harder to filter out because they interfere with the true signal, causing effects almost indistinguishable from routine fluctuations in atmospheric delay.
Multipath effects are much less severe in moving vehicles. When the GPS antenna is moving, the false solutions using reflected signals quickly fail to converge and only the direct signals result in stable solutions.
[edit] Ephemeris and clock errors
While the ephemeris data is transmitted every 30 seconds, the information itself may be up to two hours old. Data up to four hours old is considered valid for calculating positions, but may not indicate the satellites actual position. If a fast TTFF is needed, it is possible to upload valid ephemeris to a receiver, and in addition to setting the time, a position fix can be obtained in under ten seconds. It is feasible to put such ephemeris data on the web so it can be loaded into mobile GPS devices. [21]
The satellite's atomic clocks experience noise and clock drift errors. The navigation message contains corrections for these errors and estimates of the accuracy of the atomic clock. However, they are based on observations and may not indicate the clock's current state.
These problems tend to be very small, but may add up to a few meters (10s of feet) of inaccuracy.[22]
[edit] Selective availability
GPS includes a (currently disabled) feature called Selective Availability (SA) that can introduce intentional, slowly changing random errors of up to a hundred meters (328 ft) into the publicly available navigation signals to confound, for example, the guidance of long range missiles to precise targets. When enabled, the accuracy is still available in the signal, but in an encrypted form that is only available to the United States military, its allies and a few others, mostly government users. Even those who have managed to acquire military GPS receivers would still need to obtain the daily key, whose dissemination is tightly controlled.
Prior to being turned off, SA typically added signal errors of up to about 10 meters (32 ft) horizontally and 30 meters (98 ft) vertically. The inaccuracy of the civilian signal was deliberately encoded so as not to change very quickly. For instance, the entire eastern U.S. area might read 30 m off, but 30 m off everywhere and in the same direction. To improve the usefulness of GPS for civilian navigation, Differential GPS was used by many civilian GPS receivers to greatly improve accuracy.
During the Gulf War, the shortage of military GPS units and the ready availability of civilian ones caused many troops to buy their own civilian GPS units: their wide use among personnel resulted in a decision to disable Selective Availability. This was ironic, as SA had been introduced specifically for these situations, allowing friendly troops to use the signal for accurate navigation, while at the same time denying it to the enemy—but the assumption underlying this policy was that all U.S. troops and enemy troops would have military-specification GPS receivers and that civilian receivers would not exist in war zones. But since many American soldiers were using civilian devices, SA was also denying the same accuracy to thousands of friendly troops; turning it off (by removing the added-in error) presented a clear benefit to friendly troops.
In the 1990s, the FAA started pressuring the military to turn off SA permanently. This would save the FAA millions of dollars every year in maintenance of their own radio navigation systems. The amount of error added was "set to zero"[23] at midnight on May 1, 2000 following an announcement by U.S. President Bill Clinton, allowing users access to the error-free L1 signal. Per the directive, the induced error of SA was changed to add no error to the public signals (C/A code). Clinton's executive order required SA to be set to zero by 2006; it happened in 2000 once the US military developed a new system that provides the ability to deny GPS (and other navigation services) to hostile forces in a specific area of crisis without affecting the rest of the world or its own military systems.[23]
Selective Availability is still a system capability of GPS, and error could, in theory, be reintroduced at any time. In practice, in view of the hazards and costs this would induce for US and foreign shipping, it is unlikely to be reintroduced, and various government agencies, including the FAA,[24] have stated that it is not intended to be reintroduced.
One interesting side effect of the Selective Availability hardware is the capability to correct the frequency of the GPS cesium and rubidium atomic clocks to an accuracy of approximately 2 × 10-13 (one in five trillion). This represented a significant improvement over the raw accuracy of the clocks.[citation needed]
On 19 September 2007, the United States Department of Defense announced that future GPS III satellites will not be capable of implementing SA,[25] eventually making the policy permanent.[26]
[edit] Relativity
Satellite clocks are slowed by its orbital speed but sped up by its distance out of the earth's gravitational well.
According to the theory of relativity, due to their constant movement and height relative to the Earth-centered inertial reference frame, the clocks on the satellites are affected by their speed (special relativity) as well as their gravitational potential (general relativity). For the GPS satellites, general relativity predicts that the atomic clocks at GPS orbital altitudes will tick more rapidly, by about 45.9 microseconds (μs) per day, because they are in a weaker gravitational field than atomic clocks on Earth's surface. Special relativity predicts that atomic clocks moving at GPS orbital speeds will tick more slowly than stationary ground clocks by about 7.2 μs per day. When combined, the discrepancy is about 38 microseconds per day; a difference of 4.465 parts in 1010.[27]. To account for this, the frequency standard onboard each satellite is given a rate offset prior to launch, making it run slightly slower than the desired frequency on Earth; specifically, at 10.22999999543 MHz instead of 10.23 MHz.[28] Since the atomic clocks on board the GPS satellites are precisely tuned, it makes the system a practical engineering application of the scientific theory of relativity in a real-world environment.
[edit] Sagnac distortion
GPS observation processing must also compensate for the Sagnac effect. The GPS time scale is defined in an inertial system but observations are processed in an Earth-centered, Earth-fixed (co-rotating) system, a system in which simultaneity is not uniquely defined. A Lorentz transformation is thus applied to convert from the inertial system to the ECEF system. The resulting signal run time correction has opposite algebraic signs for satellites in the Eastern and Western celestial hemispheres. Ignoring this effect will produce an east-west error on the order of hundreds of nanoseconds, or tens of meters in position.[29]
[edit] GPS interference and jamming
[edit] Natural sources
Since GPS signals at terrestrial receivers tend to be relatively weak, it is easy for other sources of electromagnetic radiation to desensitize the receiver, making acquiring and tracking the satellite signals difficult or impossible.
Solar flares are one such naturally occurring emission with the potential to degrade GPS reception, and their impact can affect reception over the half of the Earth facing the sun. GPS signals can also be interfered with by naturally occurring geomagnetic storms, predominantly found near the poles of the Earth's magnetic field.[30] GPS signals are also subjected to interference from Van Allen Belt radiation when the satellites pass through the South Atlantic Anomaly.
[edit] Artificial sources
Metallic features in windshields[31], such as defrosters, or car window tinting films[32] can act as a Faraday cage, degrading reception just inside the car.
Man-made EMI can also disrupt, or jam, GPS signals. In one well documented case, an entire harbor was unable to receive GPS signals due to unintentional jamming caused by a malfunctioning TV antenna preamplifier.[33] Intentional jamming is also possible. Generally, stronger signals can interfere with GPS receivers when they are within radio range, or line of sight. In 2002, a detailed description of how to build a short range GPS L1 C/A jammer was published in the online magazine Phrack.[34]
The U.S. government believes that such jammers were used occasionally during the 2001 war in Afghanistan and the U.S. military claimed to destroy a GPS jammer with a GPS-guided bomb during the Iraq War.[35] Such a jammer is relatively easy to detect and locate, making it an attractive target for anti-radiation missiles. The UK Ministry of Defence tested a jamming system in the UK's West Country on 7 and 8 June 2007. [36]
Some countries allow the use of GPS repeaters to allow for the reception of GPS signals indoors and in obscured locations, however, under EU and UK laws, the use of these is prohibited as the signals can cause interference to other GPS receivers that may receive data from both GPS satellites and the repeater.
Due to the potential for both natural and man-made noise, numerous techniques continue to be developed to deal with the interference. The first is to not rely on GPS as a sole source. According to John Ruley, "IFR pilots should have a fallback plan in case of a GPS malfunction".[37] Receiver Autonomous Integrity Monitoring (RAIM) is a feature now included in some receivers, which is designed to provide a warning to the user if jamming or another problem is detected. The U.S. military has also deployed their Selective Availability / Anti-Spoofing Module (SAASM) in the Defense Advanced GPS Receiver (DAGR). In demonstration videos, the DAGR is able to detect jamming and maintain its lock on the encrypted GPS signals during interference which causes civilian receivers to lose lock.[38]
[edit] Techniques to improve accuracy
[edit] Augmentation
Main article: GNSS Augmentation
Augmentation methods of improving accuracy rely on external information being integrated into the calculation process. There are many such systems in place and they are generally named or described based on how the GPS sensor receives the information. Some systems transmit additional information about sources of error (such as clock drift, ephemeris, or ionospheric delay), others provide direct measurements of how much the signal was off in the past, while a third group provide additional navigational or vehicle information to be integrated in the calculation process.
Examples of augmentation systems include the Wide Area Augmentation System, Differential GPS, Inertial Navigation Systems and Assisted GPS.
[edit] Precise monitoring
The accuracy of a calculation can also be improved through precise monitoring and measuring of the existing GPS signals in additional or alternate ways.
After SA, which has been turned off, the largest error in GPS is usually the unpredictable delay through the ionosphere. The spacecraft broadcast ionospheric model parameters, but errors remain. This is one reason the GPS spacecraft transmit on at least two frequencies, L1 and L2. Ionospheric delay is a well-defined function of frequency and the total electron content (TEC) along the path, so measuring the arrival time difference between the frequencies determines TEC and thus the precise ionospheric delay at each frequency.
Receivers with decryption keys can decode the P(Y)-code transmitted on both L1 and L2. However, these keys are reserved for the military and "authorized" agencies and are not available to the public. Without keys, it is still possible to use a codeless technique to compare the P(Y) codes on L1 and L2 to gain much of the same error information. However, this technique is slow, so it is currently limited to specialized surveying equipment. In the future, additional civilian codes are expected to be transmitted on the L2 and L5 frequencies (see GPS modernization, below). Then all users will be able to perform dual-frequency measurements and directly compute ionospheric delay errors.
A second form of precise monitoring is called Carrier-Phase Enhancement (CPGPS). The error, which this corrects, arises because the pulse transition of the PRN is not instantaneous, and thus the correlation (satellite-receiver sequence matching) operation is imperfect. The CPGPS approach utilizes the L1 carrier wave, which has a period 1000 times smaller than that of the C/A bit period, to act as an additional clock signal and resolve the uncertainty. The phase difference error in the normal GPS amounts to between 2 and 3 meters (6 to 10 ft) of ambiguity. CPGPS working to within 1% of perfect transition reduces this error to 3 centimeters (1 inch) of ambiguity. By eliminating this source of error, CPGPS coupled with DGPS normally realizes between 20 and 30 centimeters (8 to 12 inches) of absolute accuracy.
Relative Kinematic Positioning (RKP) is another approach for a precise GPS-based positioning system. In this approach, determination of range signal can be resolved to a precision of less than 10 centimeters (4 in). This is done by resolving the number of cycles in which the signal is transmitted and received by the receiver. This can be accomplished by using a combination of differential GPS (DGPS) correction data, transmitting GPS signal phase information and ambiguity resolution techniques via statistical tests—possibly with processing in real-time (real-time kinematic positioning, RTK).
[edit] GPS time and date
While most clocks are synchronized to Coordinated Universal Time (UTC), the atomic clocks on the satellites are set to GPS time. The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections which are periodically added to UTC. GPS time was set to match Coordinated Universal Time (UTC) in 1980, but has since diverged. The lack of corrections means that GPS time remains at a constant offset (19 seconds) with International Atomic Time (TAI). Periodic corrections are performed on the on-board clocks to correct relativistic effects and keep them synchronized with ground clocks.[citation needed]
The GPS navigation message includes the difference between GPS time and UTC, which as of 2006 is 14 seconds due to the leap second added to UTC December 31st of 2005. Receivers subtract this offset from GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) which, at the current rate of change of the Earth's rotation, is sufficient to last until the year 2330.[citation needed]
As opposed to the year, month, and day format of the Gregorian calendar, the GPS date is expressed as a week number and a day-of-week number. The week number is transmitted as a ten-bit field in the C/A and P(Y) navigation messages, and so it becomes zero again every 1,024 weeks (19.6 years). GPS week zero started at 00:00:00 UTC (00:00:19 TAI) on January 6, 1980 and the week number became zero again for the first time at 23:59:47 UTC on August 21, 1999 (00:00:19 TAI on August 22, 1999). To determine the current Gregorian date, a GPS receiver must be provided with the approximate date (to within 3,584 days) to correctly translate the GPS date signal. To address this concern the modernized GPS navigation messages use a 13-bit field, which only repeats every 8,192 weeks (157 years), and will not return to zero until near the year 2137.[citation needed]
[edit] GPS modernization
Main article: GPS modernization
|
This article or section needs to be updated.
Please update the article to reflect recent events / newly available information, and remove this template when finished. |
Having reached the program's requirements for Full Operational Capability (FOC) on July 17, 1995,[39] the GPS completed its original design goals. However, additional advances in technology and new demands on the existing system led to the effort to modernize the GPS. Announcements from the U.S. Vice President and the White House in 1998 initiated these changes, and in 2000 the U.S. Congress authorized the effort, referring to it as GPS III.
The project aims to improve the accuracy and availability for all users and involves new ground stations, new satellites, and four additional navigation signals. New civilian signals are called L2C, L5 and L1C; the new military code is called M-Code. Initial Operational Capability (IOC) of the L2C code is expected in 2008.[40] A goal of 2013 has been established for the entire program, with incentives offered to the contractors if they can complete it by 2011 (See GPS signals).
[edit] Applications
The Global Positioning System, while originally a military project, is considered a dual-use technology, meaning it has significant applications for both the military and the civilian industry.
[edit] Military
The military applications of GPS span many purposes:
- Navigation: GPS allows soldiers to find objectives in the dark or in unfamiliar territory, and to coordinate the movement of troops and supplies. The GPS-receivers commanders and soldiers use are respectively called the Commanders Digital Assistant and the Soldier Digital Assistant.[41][42][43][44]
- Target tracking: Various military weapons systems use GPS to track potential ground and air targets before they are flagged as hostile.[citation needed] These weapon systems pass GPS co-ordinates of targets to precision-guided munitions to allow them to engage the targets accurately. Military aircraft, particularly those used in air-to-ground roles use GPS to find targets (for example, gun camera video from AH-1 Cobras in Iraq show GPS co-ordinates that can be looked up in Google Earth[citation needed]).
- Missile and projectile guidance: GPS allows accurate targeting of various military weapons including ICBMs, cruise missiles and precision-guided munitions. Artillery projectiles with embedded GPS receivers able to withstand accelerations of 12,000G have been developed for use in 155 mm howitzers.[45]
- Search and Rescue: Downed pilots can be located faster if they have a GPS receiver.
- Reconnaissance and Map Creation: The military use GPS extensively to aid mapping and reconnaissance.
- The GPS satellites also carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an Electro-Magnetic Pulse (EMP) sensor (W-sensor) which form a major portion of the United States Nuclear Detonation Detection System.[46][47]
[edit] Civilian
See also: GNSS applications and GPS navigation device
This antenna is mounted on the roof of a hut containing a scientific experiment needing precise timing.
Many civilian applications benefit from GPS signals, using one or more of three basic components of the GPS: absolute location, relative movement, and time transfer.
The ability to determine the receiver's absolute location allows GPS receivers to perform as a surveying tool or as an aid to navigation. The capacity to determine relative movement enables a receiver to calculate local velocity and orientation, useful in vessels or observations of the Earth. Being able to synchronize clocks to exacting standards enables time transfer, which is critical in large communication and observation systems. An example is CDMA digital cellular. Each base station has a GPS timing receiver to synchronize its spreading codes with other base stations to facilitate inter-cell hand off and support hybrid GPS/CDMA positioning of mobiles for emergency calls and other applications. Finally, GPS enables researchers to explore the Earth environment including the atmosphere, ionosphere and gravity field. GPS survey equipment has revolutionized tectonics by directly measuring the motion of faults in earthquakes.
To help prevent civilian GPS guidance from being used in an enemy's military or improvised weaponry, the US Government controls the export of civilian receivers. A US-based manufacturer cannot generally export a GPS receiver unless the receiver contains limits restricting it from functioning when it is simultaneously (1) at an altitude above 18 kilometers (60,000 ft) and (2) traveling at over 515 m/s (1,000 knots).[48] These parameters are well above the operating characteristics of the typical cruise missile, but would be characteristic of the reentry vehicle from a ballistic missile.
GPS functionality has now started to move into mobile phones en masse. The first GSM handsets with integrated GPS were launched already in the late 1990’s, and were available for broader consumer availability on networks such as those run by Nextel, Sprint and Verizon in 2002 in response to US FCC mandates for handset positioning in emergency calls. Capabilities for access by third party software developers to these features were slower in coming, with Nextel opening those APIs up upon launch to any developer, Sprint following in 2006, and Verizon soon thereafter.
[edit] History
The design of GPS is based partly on the similar ground-based radio navigation systems, such as LORAN and the Decca Navigator developed in the early 1940s, and used during World War II. Additional inspiration for the GPS came when the Soviet Union launched the first Sputnik in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik's radio transmissions. They discovered that, because of the Doppler effect, the frequency of the signal being transmitted by Sputnik was higher as the satellite approached, and lower as it continued away from them. They realized that since they knew their exact location on the globe, they could pinpoint where the satellite was along its orbit by measuring the Doppler distortion.
The first satellite navigation system, Transit, used by the United States Navy, was first successfully tested in 1960. Using a constellation of five satellites, it could provide a navigational fix approximately once per hour. In 1967, the U.S. Navy developed the Timation satellite which proved the ability to place accurate clocks in space, a technology the GPS relies upon. In the 1970s, the ground-based Omega Navigation System, based on signal phase comparison, became the first world-wide radio navigation system.
The first experimental Block-I GPS satellite was launched in February 1978.[40] The GPS satellites were initially manufactured by Rockwell International (now part of Boeing) and are now manufactured by Lockheed Martin (IIR/IIR-M) and Boeing (IIF).
Zdá sa, že slovenský kurz je obsažnejší: aj ostrá streľba, skákanie z vrtuľníka do vody a pod.
https://cestovani.idnes.cz/drahanska-vrchovina-morava-repessky-zleb-repechy-fvp-/po-cesku.aspx?c=A171114_130018_kolem-sveta_hig
Komentáre