Ntle le tcp/ip, ho na le mekhoa e mengata ea ho hokahanya nako. Tse ling tsa tsona li hloka mohala o tloaelehileng feela, ha tse ling li hloka lisebelisoa tsa elektronike tse theko e boima, tse sa tloaelehang le tse hlokolosi. Meaho e pharalletseng ea litsamaiso tsa khokahano ea nako e kenyelletsa libaka tsa ho shebella, litsi tsa mmuso, liteishene tsa seea-le-moea, lihlopha tsa linaleli tsa satellite le tse ling tse ngata.
Kajeno ke tla u joetsa hore na khokahano ea nako e sebetsa joang ntle le Marang-rang le mokhoa oa ho etsa seva sa "satellite" NTP ka matsoho a hau.
Khaso ea seea-le-moea sa Shortwave
United States, NIST e fetisetsa nako e nepahetseng le khafetsa ho maqhubu a seea-le-moea a 2.5, 5, 10, 15 le 20 MHz ho tloha WWVH e Fort Collins, Colorado, le ka 2.5, 5, 10 le 15 MHz ho tloha WWVH e Kauai State of Hawaii. . Khoutu ea nako e fetisoa ka nako ea metsotsoana e 60 ho 1 bps. o sebelisa ho feto-fetoha ha molumo oa pulse width ho 100 Hz subcarrier.
National Research Council (NRC) ea Canada e aba lintlha tsa nako le khafetsa ho 3.33, 7.85 le 14.67 MHz ho tloha CHU e Ottawa, Ontario.
Sebopeho sa phatlalatso sa WWVH
Phatlalatso ea lipontšo ho tloha liteisheneng tsa maqhubu a makhutšoane hangata e etsahala ka ho bonahatsa likarolo tse ka holimo tsa ionosphere. Phetiso ea matšoao e ka amoheloa libakeng tse telele, empa ho nepahala ha nako ho latela millisecond e le 'ngoe.
Tekanyetso ea hajoale ea NTPv4 e kenyelletsa li-driver tsa audio tsa WWV, WWVH le CHU.
Khaso ea seea-le-moea sa Longwave
NIST e boetse e fetisa nako le maqhubu a nepahetseng ka seea-le-moea sa nako e telele ho 60 kHz ho tloha Boulder, Colorado. Ho na le liteishene tse ling tse fetisang matšoao a nako ka maqhubu a malelele.
Mehala ea matšoao le sebaka
Hangata (kHz)
Matla (kW)
WWVB Fort Collins, Colorado, USA
60
50
DCF77 Mainflingen, Jeremane
77.5
30
MSF Rugby, United Kingdom
EA-60>
50
HBG Prangins, Switzerland
75
20
JJY Fukushima, Japane
40
50
JJY Saga, Japane
60
50
Liteishene tsa Nako tse Tloaelehileng tsa Maqhubu a Tlase
Khoutu ea nako e fetisoa ka nako ea metsotsoana e 60 ho 1 bps, joalo ka liteishene tsa shortwave. Lifomate tsa phetiso ea data le tsona li ts'oana le litekanyetso ka bobeli. Letšoao le hasana ka likarolo tse ka tlaase tsa ionosphere, tse batlang li tsitsitse 'me li na le phapang ea letsatsi le letsatsi ea bophahamo. Ka lebaka la ts'ebetso ena ea ho bolela esale pele ea tikoloho ea 'mele, ho nepahala ho nyolohela ho 50 μs.
Mofuta oa phatlalatso oa WWVB
Sathelaete ea tikoloho ea ts'ebetso ea Geostationary
Naheng ea Amerika, NIST e boetse e fetisa lintlha tse nepahetseng tsa nako le khafetsa ka hoo e ka bang 468 MHz ho tsoa ho Geostationary Operational Environmental Satellites (GOES). Khoutu ea nako e fapanyetsana le melaetsa e sebelisoang ho khetha lisensara tse hole. E na le li-nibble tse 60 tsa BCD tse fetisoang ka nako ea 30 s. Lintlha tsa khoutu ea nako li tšoana le lits'ebeletso tsa lefats'e.
Litsamaiso tsa boemo ba lefatše
Lefapha la Tšireletso la United States le sebelisa GPS bakeng sa ho tsamaea ka mokhoa o nepahetseng lefatšeng, leoatleng le moeeng. Sistimi ena e fana ka tšireletso ea lihora tse 24 lefatšeng ka bophara e sebelisa sehlopha sa linaleli sa lisathelaete tse potolohang lihora tse 12 tse sekametseng ho 55°.
Sehlopha sa pele sa linaleli sa lisathelaete tse 24 se ile sa atolosoa ho li-sathelaete tse 31 ka tlhophiso e fapaneng hoo bonyane li-sathelaete tse 6 li lulang li le teng, 'me li-sathelaete tse 8 kapa ho feta li bonoa lefatšeng ka bophara.
Litšebeletso tse tšoanang le GPS li ntse li sebelisoa kapa li reriloe ke linaha tse ling. GLONASS ea Russia e 'nile ea sebetsa ka lilemo tse leshome le metso e' meli, haeba u bala ho tloha ka la 2 Loetse, 2010, ha palo eohle ea satellite e eketsoa ho 26 - sehlopha sa linaleli se ile sa sebelisoa ka botlalo ho koahela Lefatše ka botlalo.
Li-satellite tsa GPS lefatšeng ka bophara.
Lenaneo la European Union la ho tsamaea ka sathelaete le bitsoa Galileo. Ho ne ho lebelletsoe hore Galileo o tla qala ho sebetsa ka 2014-2016, ha li-satellite tsohle tse 30 tse reriloeng li tla hlahisoa ho potoloha.
Ho boetse ho na le Sechaena "Beidou", e bolelang "leruarua". Sehlopha sa linaleli sa lisathelaete tse 16 se ile sa thakholoa tšebetsong ea khoebo ka la 27 Tšitoe 2012, e le mokhoa oa ho beha maemo sebakeng. Ho reriloe hore sistimi e tla fihlela bokhoni bo felletseng ka 2020. Kajeno feela, ke tsoile ka Habré , mabapi le ho hlahisoa ka katleho ha satellite ea tsamaiso ena.
Lipalo tsa ho khetholla likhokahano ho sebelisa SRNS
Sesepedi sa GPS/GLONASS se ho smartphone ya hao se tseba jwang sebaka seo o leng ho sona ka nepo e kaalo ka ho sebedisa mokgwa wa puisano wa radio navigation (SRNS)? Ho utloisisa molao-motheo oa lipalo, o hloka ho hopola sterometry le algebra sekolong se phahameng, kapa sekolo sa fisiks le lipalo.
Sathelaete ka 'ngoe e bolella moamoheli nako e nepahetseng. Sathelaete e na le oache ea athomo ka hona e ka tšeptjoa. Ka ho tseba lebelo la khanya, ha ho thata ho fumana sebaka sa radius ea sphere holim'a sebaka seo sathelaete e leng ho sona. Sebaka sona sena, ha se kopana le Lefatše, se etsa selikalikoe moo moamoheli oa GPS / Glonass a leng teng.
Ha lets'oao le fihla ho lisathelaete tse peli, re se re ntse re e-na le mateano a Lefatše le likarolo tse peli, tse fanang ka lintlha tse peli feela ho selikalikoe. Karolo ea satellite ea boraro e lokela ho oela ho e 'ngoe ea lintlha tsena tse peli, e qetellang e khetholla lihokahanyo tsa moamoheli.
Ha e le hantle, esita le ho tloha ho li-satellite tse peli, tse thehiloeng bopaking bo sa tobang, motho a ka utloisisa hore na ke lintlha life tse peli tse haufi le 'nete,' me li-algorithms tsa morao-rao tsa tsamaiso ea tsamaiso li ka sebetsana ka katleho le mosebetsi ona. Joale ke hobane'ng ha re hloka sathelaete ea bone?
Ho khetha sebaka ka ho sebelisa sehlopha sa linaleli sa satellite.
Ho bonolo ho bona hore setšoantšong sena se loketseng ho na le li-nuances tse ngata tseo ho nepahala ha lipalo ho itšetlehileng ka tsona. Nako ea ho amohela mohlomong ke mohloli o totobetseng oa phoso. E le hore ntho e 'ngoe le e 'ngoe e sebetse kamoo e lokelang, nako ea ho amohela GPS/Glonass e tlameha ho amahanngoa le nako ea sathelaete. Ntle le sena, phoso e ka ba ∓ lik'hilomithara tse likete tse 100.
Ho tsoa ho foromo ea lebelo, nako le sebaka S = v * t re fumana equation ea motheo bakeng sa ho fetisa letšoao la SRNS. Sebaka sa sathelaete se lekana le sehlahisoa sa lebelo la khanya le phapang ea nako ho sathelaete le moamoheli.
Sena se bakoa haholo ke taba ea hore esita le ka mor'a li-synchronization tsohle, re tseba nako tpr ho moamoheli ka tekanyo e lekaneng ea ho nepahala. Pakeng tsa nako ea 'nete le tpr ho tla lula ho na le Δt, ka lebaka leo phoso ea lipalo e fetohang e sa amoheleheng. Ke kahoo o hlokang ea bone sathelaete.
Bakeng sa mabaka a hlakileng a lipalo bakeng sa tlhokahalo ea lisathelaete tse 'nè, re tla theha tsamaiso ea lipalo.
Ho fumana tse 'nè tse sa tsejoeng x, y, z, le Δt, palo ea litebello e tlameha ho lekana kapa e kholo ho feta palo ea tse sa tsejoeng. Ena ke boemo bo hlokahalang empa bo sa lekana. Haeba matrix ea equations e tloaelehileng e fetoha bonngoe, tsamaiso ea li-equations e ke ke ea e-ba le tharollo.
Hape ha rea lokela ho lebala ka Khopolo e Khethehileng ea Kamano le litlamorao tse amanang le katoloso ea nako ho lioache tsa athomo tsa sathelaete tse amanang le tsa fatše.
Haeba re nka hore sathelaete e ntse e tsamaea ka lebelo la lik'hilomithara tse likete tse 14 / h, joale re fumana nako ea ho fokotseha ho ka bang 7 μs (microseconds). Ka lehlakoreng le leng, liphello tsa relativistic tsa Khopolo-Kakaretso ea Relativity li sebetsa.
Taba ke ena: lisathelaete tse ho orbit li hole haholo ho tloha Lefatšeng, moo ho kobeha ha nako ea nako ea sebaka ho leng ka tlase ho holim'a Lefatše ka lebaka la boima ba Lefatše. Ho latela kamano e akaretsang, lioache tse haufi le ntho e kholo li tla bonahala li le butle ho feta tse leng hole le eona.
- G ke matla a khoheli a sa fetoheng;
- M ke boima ba ntho, tabeng ena Lefatše;
- r ke sebaka sa ho tloha bohareng ba Lefatše ho ea sathelaete;
- c ke lebelo la kganya.
Palo e sebelisang foromo ena e fana ka katoloso ea nako ea 45 μs sathelaete. Kakaretso -7μs +45μs = 38μs ho leka-lekana - liphello tsa STR le GTR.
Lits'ebetsong tsa boemo ba SRNS, tieho ea ionospheric le tropospheric le eona e lokela ho nkoa. Ho feta moo, litokiso tsa 46 ns li bakoa ke 0.02 eccentricity ea GPS satellites' orbit.
Bokhoni ba ho amohela matšoao ka nako e le 'ngoe ho tsoa ho li-satellite tse fetang tse' ne tsa GPS / GLONASS li u lumella ho eketsa ho nepahala ha lihokela tsa moamoheli. Sena se finyelloa ka lebaka la hore navigator o rarolla tsamaiso ea li-equations tse 'nè tse nang le tse' nè tse sa tsejoeng palo ea makhetlo 'me e nka boleng ba karolelano, ho eketsa ho nepahala ha khakanyo ea ho qetela ho ea ka melao ea lipalo-palo tsa lipalo.
Mokhoa oa ho lokisa seva sa NTP Stratum 1 ka khokahano ea sathelaete
Ho theha sebatli sa nako ea boleng bo holimo, o hloka feela GPSD, NTP le moamoheli oa GPS o nang le 1PPS (pulse e le 'ngoe ka motsotsoana).
1. Kenya gpsd le ntpd, kapa gpsd le chronyd. Mofuta oa GPSD o tlameha ho ba ≥ 3.20
(1:1109)$ sudo emerge -av gpsd chrony
Local copy of remote index is up-to-date and will be used.
Calculating dependencies... done!
[binary N ] net-misc/pps-tools-0.0.20120407::gentoo 31 KiB
[binary N ] net-misc/chrony-3.5-r2::gentoo USE="adns caps cmdmon ipv6 ntp phc readline refclock rtc seccomp (-html) -libedit -pps (-selinux)" 246 KiB
[binary N ] sci-geosciences/gpsd-3.17-r3:0/23::gentoo USE="X bluetooth cxx dbus ipv6 ncurses python shm sockets udev usb -debug -latency-timing -ntp -qt5 -static -test" GPSD_PROTOCOLS="aivdm ashtech earthmate evermore fv18 garmin garmintxt gpsclock isync itrax mtk3301 navcom ntrip oceanserver oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 tnt tripmate tsip ublox -fury -geostar -nmea0183 -nmea2000 -passthrough" PYTHON_TARGETS="python2_7" 999 KiB
Total: 3 packages (3 new, 3 binaries), Size of downloads: 1275 KiB
Would you like to merge these packages? [Yes/No]2. Hokela moamoheli oa GPS ka tšehetso ea PPS ho seriale sa RS232 kapa boema-kepe ba USB.
Moamoheli oa kamehla oa GPS o theko e tlase o ke ke oa sebetsa; U ka tlameha ho batla ho se hokae ho fumana e nepahetseng.
3. Etsa bonnete ba hore sesebelisoa se fana ka PPS, ho etsa sena, hlahloba boema-kepe ka ts'ebeliso ea gpsmon.
4. Bula faele ea /etc/conf.d/gpsd 'me u lokise mola o latelang.
Kenya sebaka
GPSD_OPTIONS=""e le hore e be
GPSD_OPTIONS="-n"Phetoho ena ea hlokahala e le hore gpsd e qale hang-hang ho batla mehloli ea SRNS ha e qala.
5. Qala kapa qala bocha gpsd.
(1:110)$ sudo /etc/init.d/gpsd start
(1:111)$ sudo /etc/init.d/gpsd restart
Bakeng sa lipehelo ka systemd, sebelisa taelo e nepahetseng ea systemctl.
6. Sheba tlhahiso ea console ea taelo ea cgps.
U hloka ho etsa bonnete ba hore data e amoheloa ka nepo ho tsoa ho lisathelaete. Consolese e lokela ho ba le ntho e tšoanang le papiso.
Sephetho sa taelo ea cgps console.
7. Ke nako ea ho fetola faele ea /etc/ntp.conf.
# GPS Serial data reference (NTP0)
server 127.127.28.0
fudge 127.127.28.0 time1 0.9999 refid GPS
# GPS PPS reference (NTP1)
server 127.127.28.1 prefer
fudge 127.127.28.1 refid PPS
Kenyelletso e holimo ea NTP0 e bonts'a mohloli oa nako oa bokahohle o fumanehang hoo e batlang e le lisebelisoa tsohle tsa GPS. Kenyelletso e tlase ea NTP1 e hlalosa mohloli o nepahetseng haholoanyane oa PPS.
8. Qala hape ntpd.
(1:112)$ sudo /etc/init.d/ntpd restart
Bakeng sa liphallelo tse nang le systemd, sebelisa taelo ea systemctl.
$ sudo systemctl qala hape ntp
Lisebelisoa tse sebelisitsoeng
- David L Mills The Network Time Protocol Lefatšeng le Sebakeng,Khatiso ea Bobeli.
Source: www.habr.com