Baya ga tcp/ip, akwai hanyoyi da yawa don daidaita lokaci. Wasu daga cikinsu suna buƙatar tarho na yau da kullun kawai, yayin da wasu suna buƙatar kayan lantarki masu tsada, ba kasafai da mahimmanci ba. Manyan abubuwan more rayuwa na tsarin aiki tare na lokaci sun haɗa da wuraren kallo, cibiyoyin gwamnati, tashoshin rediyo, taurarin tauraron dan adam da ƙari mai yawa.
A yau zan gaya muku yadda aiki tare da lokaci ke aiki ba tare da Intanet ba da kuma yadda ake yin sabar NTP ta “Satellite” da hannuwanku.
Shortwave rediyo watsa shirye-shirye
A cikin Amurka, NIST tana watsa madaidaicin lokaci da mita akan 2.5, 5, 10, 15 da 20 MHz raƙuman radiyo daga WWVH a Fort Collins, Colorado, da kuma akan 2.5, 5, 10 da 15 MHz daga WWVH a Kauai. Jihar Hawaii . Ana watsa lambar lokaci a tazarar daƙiƙa 60 a 1 bps. ta amfani da juzu'in juzu'in juzu'in juzu'i akan mai ɗaukar nauyin 100 Hz.
Majalisar Bincike ta Kasa (NRC) na Kanada tana rarraba bayanai na lokaci da mita akan 3.33, 7.85 da 14.67 MHz daga CHU a Ottawa, Ontario.
Tsarin Watsa shirye-shiryen WMVH
Yada siginar daga tashoshi na gajeriyar igiyar igiyar ruwa yawanci yana faruwa ta hanyar tunani daga saman saman ionosphere. Ana iya karɓar watsa siginar ta nisa mai nisa, amma daidaiton lokacin yana kan tsari na millisecond ɗaya.
Ma'aunin NTPv4 na yanzu ya haɗa da direbobin sauti don WWV, WMVH da CHU.
Longwave rediyo watsa shirye-shirye
NIST kuma tana watsa madaidaicin lokaci da mitar akan rediyo mai tsayi a 60 kHz daga Boulder, Colorado. Akwai wasu tashoshi masu watsa sigina na lokaci akan dogayen igiyoyin ruwa.
Alamomin kira da wuri
Mitar (kHz)
Ƙarfi (kW)
WWVB Fort Collins, Colorado, Amurika
60
50
DCF77 Mainflingen, Jamus
77.5
30
MSF Rugby, Birtaniya
60>
50
HBG Prangins, Switzerland
75
20
JJY Fukushima, Japan
40
50
JJY Saga, Japan
60
50
Matsakaicin Matsakaicin Matsakaicin Matsakaicin Lokaci
Ana watsa lambar lokacin a cikin tazarar daƙiƙa 60 a 1 bps, kamar tashoshi na gajeriyar igiyar ruwa. Tsarin watsa bayanai kuma suna kama da ma'auni biyu. Sigina yana yaduwa ta cikin ƙananan yadudduka na ionosphere, waɗanda ke da kwanciyar hankali kuma suna da bambance-bambancen yau da kullun a tsayi. Godiya ga wannan tsinkayar yanayin yanayin jiki, daidaito yana ƙaruwa zuwa 50 μs.
Tsarin watsa shirye-shiryen WWVB
Geostationary aiki tauraron dan adam muhalli
A cikin Amurka, NIST kuma tana watsa madaidaicin bayanai na lokaci da mitar akan kusan 468 MHz daga Tauraron Dan Adam na Ayyukan Muhalli na Geostationary (GOES). Lambar lokaci tana musanya tare da saƙonnin da aka yi amfani da su don jefa kuri'a na firikwensin nesa. Ya ƙunshi nibbles 60 BCD da ake watsawa a tazara 30 s. Bayanan lambar lokaci yayi kama da sabis na ƙasa.
Tsarin sakawa na duniya
Ma'aikatar Tsaro ta Amurka tana amfani da GPS don kewayawa na musamman akan ƙasa, ruwa da iska. Tsarin yana ba da ɗaukar hoto na sa'o'i 24 na duniya ta amfani da taurarin tauraron dan adam a cikin sa'o'i 12 da ke karkata a 55 °.
An fadada asalin taurarin tauraron dan adam 24 zuwa tauraron dan adam 31 a cikin tsari daban-daban ta yadda a kalla tauraron dan adam 6 ake gani ko da yaushe, kuma tauraron dan adam 8 ko sama da haka ana gani a mafi yawan duniya.
Wasu ƙasashe suna sarrafa ko tsara ayyuka irin na GPS. Rasha GLONASS tana aiki tsawon shekaru goma sha biyu, idan ka ƙidaya daga ranar 2 ga Satumba, 2010, lokacin da aka ƙara adadin tauraron dan adam zuwa 26 - an tura ƙungiyar ta taurari gaba ɗaya don rufe duniya gaba ɗaya.
GPS tauraron dan adam a duk duniya.
Tsarin kewaya tauraron dan adam na Tarayyar Turai ana kiransa Galileo. Ana sa ran Galileo zai fara aiki a shekarar 2014-2016, lokacin da za a harba dukkan tauraron dan adam 30 da aka tsara zuwa sararin samaniya. Amma a shekarar 2018, tauraron dan adam na Galileo bai kai adadin tauraron dan adam da ake bukata ba.
Akwai kuma "Beidou" na kasar Sin, wanda ke nufin "Whale". An harba tauraron tauraron dan adam 16 zuwa cikin kasuwanci a ranar 27 ga Disamba, 2012, a matsayin tsarin sakawa yanki. An shirya cewa tsarin zai kai ga cikakken iko nan da shekarar 2020. Kawai yau, na fito kan Habré , game da nasarar harba tauraron dan adam na wannan tsarin.
Lissafi na ƙayyadaddun haɗin kai ta amfani da SRNS
Ta yaya GPS/GLONASS navigator akan wayoyinku ke tantance wurin da irin wannan daidaito ta amfani da tsarin sadarwar kewayawa ta rediyo (SRNS)? Don fahimtar ƙa'idar lissafi, kuna buƙatar tunawa da stereometry da algebra a makarantar sakandare, ko makarantar kimiyyar lissafi da lissafi.
Kowane tauraron dan adam yana gaya wa mai karɓa daidai lokacin. Tauraron dan adam yana da agogon atomic don haka ana iya amincewa da shi. Sanin saurin haske, ba shi da wahala a tantance radius na sphere a saman wanda tauraron dan adam yake. Wannan yanki ɗaya, a cikin hulɗa da Duniya, yana samar da da'irar da mai karɓar GPS / Glonass yake.
Lokacin da siginar ya zo daga tauraron dan adam guda biyu, mun riga mun sami hanyar haɗin duniya da bangarori biyu, wanda ke ba da maki biyu kawai akan da'irar. Yankin tauraron dan adam na uku yakamata ya fada cikin daya daga cikin wadannan maki biyu, a karshe yana tantance ma'auni na mai karba.
A ka'ida, ko da daga tauraron dan adam guda biyu, bisa ga shaidar kai tsaye, mutum zai iya fahimtar wanne daga cikin maki biyun ya fi kusa da gaskiya, kuma algorithms software na kewayawa na zamani na iya jure wa wannan aikin. Me yasa muke buƙatar tauraron dan adam na huɗu?
Ƙayyade wuri ta amfani da tauraron dan adam.
Yana da sauƙin ganin cewa a cikin wannan kyakkyawan hoto akwai nuances da yawa waɗanda daidaiton lissafin ya dogara. Lokaci mai karɓa watakila shine mafi bayyananne tushen kuskure. Domin komai ya yi aiki yadda ya kamata, dole ne a daidaita lokacin karɓar GPS/Glonass tare da lokacin tauraron dan adam. Idan ba tare da wannan ba, kuskuren zai zama ∓ 100 km.
Daga dabarar gudun, lokaci da nisa S = v*t muna samun ainihin ma'auni don watsa siginar SRNS. Nisa zuwa tauraron dan adam daidai yake da samfurin saurin haske da bambancin lokaci akan tauraron dan adam da mai karɓa.
Wannan ya faru ne saboda gaskiyar cewa ko da bayan duk aiki tare, mun san lokacin tpr a mai karɓa tare da isasshen matakin daidaito. Tsakanin lokaci na gaskiya da tpr koyaushe za a sami Δt, saboda wanda kuskuren lissafin ya zama wanda ba a yarda da shi ba. Shi ya sa kuke bukata na huɗu tauraron dan adam.
Don ƙarin hujjar ilimin lissafi don buƙatar tauraron dan adam guda huɗu, za mu gina tsarin daidaitawa.
Don tantance abubuwan da ba a sani ba guda huɗu x, y, z, da Δt, adadin abubuwan lura dole ne ya zama daidai ko girma fiye da adadin waɗanda ba a san su ba. Wannan ya zama dole amma bai isa ba. Idan matrix na al'ada equations ya juya ya zama guda ɗaya, tsarin lissafin ba zai sami mafita ba.
Kada kuma mu manta game da Ka'idar Dangantaka ta Musamman da tasirin alaƙa tare da haɓaka lokaci akan agogon atomic na tauraron dan adam dangane da na ƙasa.
Idan muka ɗauka cewa tauraron dan adam yana tafiya a cikin kewayawa a cikin gudun kilomita 14 a cikin sa'a, to, za mu sami lokacin dilation na kimanin 7 μs (microseconds). A gefe guda kuma, tasirin kamanceceniya na Babban Ka'idar Dangantaka yana aiki.
Maganar ita ce: tauraron dan adam da ke kewayawa yana da nisa mai nisa daga doron kasa, inda karkatar da lokacin sararin samaniya bai kai na saman duniya ba saboda yawan duniya. Dangane da alaƙar gabaɗaya, agogon da ke kusa da wani babban abu zai bayyana a hankali fiye da waɗanda ke nesa da shi.
- G shine madaidaicin nauyi;
- M shine nauyin abu, a cikin wannan yanayin Duniya;
- r shine nisa daga tsakiyar duniya zuwa tauraron dan adam;
- c shine gudun haske.
Ƙididdigar yin amfani da wannan dabara yana ba da faɗar lokaci na 45 μs akan tauraron dan adam. Jimlar -7μs +45μs = 38μs ma'auni - tasirin STR da GTR.
A cikin aikace-aikacen sakawa na SRNS, ionospheric da jinkirin tropospheric ya kamata kuma a yi la'akari da su. Bugu da ƙari, gyare-gyaren 46 ns sun kasance saboda 0.02 eccentricity na tauraron dan adam na GPS.
Ikon karɓar sigina a lokaci guda daga tauraron dan adam sama da hudu GPS / GLONASS yana ba ku damar ƙara daidaiton ƙayyadaddun daidaitawar mai karɓa. Ana samun wannan ne saboda gaskiyar cewa mai kewayawa yana warware tsarin daidaitawa guda huɗu tare da waɗanda ba a san su ba adadin lokuta kuma yana ɗaukar matsakaicin ƙima, yana ƙara daidaiton ƙimar ƙarshe bisa ga dokokin ƙididdiga na lissafi.
Yadda ake saita uwar garken NTP Stratum 1 ta hanyar haɗin tauraron dan adam
Don saita sabar lokaci mai inganci, kawai kuna buƙatar GPSD, NTP da mai karɓar GPS tare da fitowar 1PPS (pulse ɗaya a sakan daya).
1. Sanya gpsd da ntpd, ko gpsd da chronyd. Dole ne sigar GPSD ta zama ≥ 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. Haɗa mai karɓar GPS tare da tallafin PPS zuwa serial RS232 ko tashar USB.
Mai karɓar GPS mai arha na yau da kullun ba zai yi aiki ba; Wataƙila za ku yi ɗan bincike don nemo wanda ya dace.
3. Tabbatar cewa na'urar tana fitar da PPS da gaske, don yin wannan, duba tashar jiragen ruwa tare da utilities gpsmon.
4. Bude fayil ɗin /etc/conf.d/gpsd kuma gyara layin da ke gaba.
Sauya
GPSD_OPTIONS=""domin ya zama
GPSD_OPTIONS="-n"Ana buƙatar wannan canjin ta yadda gpsd nan da nan ya fara nemo hanyoyin SRNS yayin farawa.
5. Fara ko sake kunna gpsd.
(1:110)$ sudo /etc/init.d/gpsd start
(1:111)$ sudo /etc/init.d/gpsd restart
Don rarrabawa tare da systemd, yi amfani da umarnin systemctl da ya dace.
6. Duba kayan aikin wasan bidiyo na umarnin cgps.
Kuna buƙatar tabbatar da cewa an karɓi bayanan daidai daga tauraron dan adam. Na'urar wasan bidiyo ya kamata ya sami wani abu mai kama da misalin.
Fitar da umarnin CGps console.
7. Lokaci yayi da za a gyara fayil ɗin /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
Babban shigarwar NTP0 yana nuna tushen lokaci na duniya da ake samu akan kusan duk na'urorin GPS. Shigarwar NTP1 na ƙasa yana bayyana ma'anar PPS mafi inganci.
8. Sake kunna ntpd.
(1:112)$ sudo /etc/init.d/ntpd restart
Don rarrabawa tare da systemd, yi amfani da umarnin systemctl.
$ sudo systemctl sake kunna ntp
Abubuwan da aka yi amfani da su
- David L Mills Yarjejeniyar Lokacin Sadarwar Yanar Gizo a Duniya da cikin Sararin Samaniya,Bugu na Biyu.
source: www.habr.com