Ma waho aʻe o tcp/ip, nui nā ala e hoʻonohonoho ai i ka manawa. Pono kekahi o lākou i kelepona maʻamau wale nō, a ʻo nā mea ʻē aʻe e koi ana i nā lako uila pipiʻi, kakaʻikahi a paʻakikī. ʻO ka ʻōnaehana nui o nā ʻōnaehana hoʻonohonoho manawa e pili ana i nā mākaʻikaʻi, nā keʻena aupuni, nā lekiō, nā constellations satellite a me nā mea hou aku.
I kēia lā, e haʻi wau iā ʻoe pehea ka hana ʻana o ka manawa me ka ʻole o ka Pūnaewele a pehea e hana ai i kahi kikowaena NTP "satellite" me kou mau lima ponoʻī.
ʻO ka hoʻolaha lekiō pōkole
Ma ʻAmelika Hui Pū ʻIa, hoʻouna ʻo NIST i ka manawa a me ka alapine pololei ma 2.5, 5, 10, 15 a me 20 MHz mau nalu lekiō mai WWVH ma Fort Collins, Colorado, a ma 2.5, 5, 10 a me 15 MHz mai WWVH ma Kauai. State of Hawaii . Hoʻouna ʻia ke code manawa ma 60 kekona manawa ma 1 bps. me ka hoʻohana ʻana i ka hoʻololi ʻana i ka laulā pulse ma kahi subcarrier 100 Hz.
Hāʻawi ka National Research Council (NRC) o Kanada i ka ʻike manawa a me ka alapine ma 3.33, 7.85 a me 14.67 MHz mai CHU ma Ottawa, Ontario.
ʻO ke ʻano hoʻolaha WWVH
ʻO ka hoʻolaha ʻana o ka hōʻailona mai nā kikowaena hawewe pōkole ma ka noʻonoʻo ʻana mai nā papa luna o ka ionosphere. Hiki ke loaʻa nā hōʻailona hōʻailona ma kahi lōʻihi, akā aia ka pololei o ka manawa ma ke kauoha o hoʻokahi millisecond.
ʻO ka maʻamau NTPv4 o kēia manawa ka mea hoʻokele leo no WWV, WWVH a me CHU.
Hoʻolaha lekiō lōʻihi
Hoʻouna pū ʻo NIST i ka manawa a me ka alapine ma ka lekiō lōʻihi ma 60 kHz mai Boulder, Colorado. Aia kekahi mau kikowaena e hoʻouna ana i nā hōʻailona manawa ma nā nalu lōʻihi.
Nā hōʻailona kelepona a me kahi
Ka pinepine (kHz)
Mana (kW)
WWVB Papu Collins, Kololoka, USA
60
50
DCF77 Mainflingen, Kelemānia
77.5
30
MSF Rugby, United Kingdom
60>
50
HBG Prangins, Kuikilana
75
20
JJY Fukushima, Iapana
40
50
JJY Saga, Iapana
60
50
Nā Kūlana Manawa Haʻahaʻa Frequency
Hoʻouna ʻia ke code manawa i 60 mau kekona ma 1 bps, e like me nā kikowaena hawewe pōkole. Ua like pū nā ʻano hoʻoili ʻikepili no nā maʻamau ʻelua. Hoʻolaha ka hōʻailona ma nā ʻaoʻao haʻahaʻa o ka ionosphere, ʻano paʻa a ʻike ʻia nā ʻokoʻa o kēlā me kēia lā i ke kiʻekiʻe. Mahalo i kēia wānana o ke kaiapuni kino, piʻi ka pololei i 50 μs.
ʻO ke ʻano hoʻolaha WWVB
Geostationary hana kaiapuni ukali
Ma US, hoʻouna pū ʻo NIST i ka ʻikepili manawa a me ka alapine ma kahi o 468 MHz mai Geostationary Operational Environmental Satellites (GOES). Hoʻololi ke code manawa me nā memo i hoʻohana ʻia no ke koho balota mamao. Loaʻa iā ia he 60 BCD nibbles i hoʻouna ʻia ma 30 mau manawa. Ua like ka ʻike helu manawa me nā lawelawe terrestrial.
Nā ʻōnaehana hoʻonohonoho honua
Hoʻohana ka US Department of Defense i GPS no ka hoʻokele pololei ʻana ma ka ʻāina, ke kai a me ka lewa. Hāʻawi ka ʻōnaehana i ka uhi ʻana o ka honua he 24 mau hola me ka hoʻohana ʻana i ka constellation o nā satelite ma nā orbit 12-hola i kuhi ʻia ma 55°.
Ua hoʻonui ʻia ka hui mua o 24 satellites i 31 satellite ma kahi hoʻonohonoho like ʻole i ʻike mau ʻia ma ka liʻiliʻi he 6 mau ukali, a ʻo 8 a ʻoi aʻe nā satelite e ʻike ʻia ma ka hapa nui o ka honua.
Hoʻohana ʻia a hoʻolālā ʻia nā lawelawe e like me GPS e nā ʻāina ʻē aʻe. Ke hana nei ʻo GLONASS Lūkini no nā makahiki he ʻumikūmākahi, inā ʻoe e helu mai ka lā 2 Kepakemapa 2010, i ka wā i hoʻonui ʻia ai ka nui o nā satelite i 26 - ua hoʻonohonoho pono ʻia ka constellation e uhi pono i ka Honua.
Nā ukali GPS a puni ka honua.
Kapa ʻia ʻo Galileo ka ʻōnaehana hoʻokele satellite o ka ʻEulopa. Ua manaʻo ʻia e hoʻomaka ʻo Galileo i ka hana ma 2014-2016, i ka wā e hoʻokuʻu ʻia ai nā satelite āpau i hoʻolālā ʻia i ka orbit.
Aia kekahi ʻōlelo Kina "Beidou", ʻo ia hoʻi "whale". Ua hoʻomaka ʻia ka hui ʻana o nā satelite he 16 i ka hana pāʻoihana ma Dekemaba 27, 2012, ma ke ʻano he ʻōnaehana hoʻonohonoho kūloko. Hoʻolālā ʻia e hōʻea ka ʻōnaehana i ka mana piha e 2020. I kēia lā wale nō, ua puka au ma Habré , e pili ana i ka hoʻomaka ʻana o kahi satellite o kēia ʻōnaehana.
ʻO ka makemakika o ka hoʻoholo ʻana i nā koina me ka hoʻohana ʻana iā SRNS
Pehea e hoʻoholo ai ka mea hoʻokele GPS/GLONASS ma kāu kelepona i kahi me ka pololei me ka hoʻohana ʻana i ka ʻōnaehana hoʻokele radio navigation (SRNS)? No ka hoʻomaopopo ʻana i ke kumu o ka helu ʻana, pono ʻoe e hoʻomanaʻo i ka stereometry a me ka algebra ma ke kula kiʻekiʻe, a i ʻole ke kula physics a me ka makemakika.
Hōʻike kēlā me kēia satellite i ka mea hoʻokipa i ka manawa pololei. He uaki atomi ko ka satellite a no laila hiki ke hilinaʻi ʻia. I ka ʻike ʻana i ka wikiwiki o ka māmā, ʻaʻole paʻakikī ke hoʻoholo i ka radius o ka pōʻai ma ka ʻili o ka satellite. ʻO kēia pōʻai like, e pili ana me ka Honua, e hana i kahi pōʻai kahi i loaʻa ai ka GPS / Glonass receiver.
Ke hōʻea mai ka hōʻailona mai nā satelite ʻelua, ua loaʻa iā mākou ka hui ʻana o ka Honua a me ʻelua mau pōʻai, e hāʻawi ana i ʻelua mau kiko ma ka pōʻai. Pono e hāʻule ka pōʻai o ka satellite ʻekolu i loko o kekahi o kēia mau wahi ʻelua, e hoʻoholo hope i nā hoʻonohonoho o ka mea hoʻokipa.
Ma ke kumu, mai nā satellite ʻelua, e pili ana i nā hōʻike indirect, hiki i kekahi ke hoʻomaopopo i kahi o nā helu ʻelua i kokoke i ka ʻoiaʻiʻo, a hiki i nā polokalamu hoʻokele hoʻokele algorithm ke hoʻokō i kēia hana. No ke aha mākou e pono ai i kahi satellite ʻehā?
Hoʻoholo i kahi me ka hoʻohana ʻana i ka constellation satellite.
He mea maʻalahi ke ʻike i loko o kēia kiʻi i hoʻohālikelike ʻia he nui nā nuances e hilinaʻi ai ka pololei o nā helu. ʻO ka manawa hoʻokipa paha ke kumu maopopo loa o ka hewa. I mea e hana ai nā mea a pau e like me ka mea e pono ai, pono e hui pū ʻia ka manawa hoʻokipa GPS / Glonass me ka manawa satellite. Inā ʻaʻole kēia, ʻo ka hewa he ∓ 100 tausani km.
Mai ke kumu no ka wikiwiki, ka manawa a me ka mamao S = v*t loaʻa iā mākou ka hoʻohālikelike kumu no ka hoʻouna ʻana i ka hōʻailona SRNS. Ua like ka mamao i ka satellite me ka huahana o ka māmā māmā a me ka ʻokoʻa o ka manawa ma ka satellite a me ka mea hoʻokipa.
ʻO kēia ma muli o ka ʻoiaʻiʻo ma hope o nā hoʻonohonoho like ʻana, ʻike mākou i ka manawa tpr ma ka mea hoʻokipa me ka lawa o ka pololei. Ma waena o ka manawa ʻoiaʻiʻo a me ka tpr e loaʻa mau ana ka Δt, no laila ʻaʻole ʻae ʻia ka hewa helu helu. ʻO ia ke kumu e pono ai ʻoe ka ha ukali.
No ka hōʻoia ʻana i ka makemakika akaka no ka pono o nā satelite ʻehā, e kūkulu mākou i kahi ʻōnaehana o nā hoohalike.
No ka hoʻoholo ʻana i nā mea ʻike ʻehā x, y, z, a me Δt, pono e like a ʻoi aku paha ka helu o nā ʻike ma mua o ka helu o nā mea ʻike ʻole. He kūlana pono kēia akā ʻaʻole lawa. Inā lilo ka matrix o nā hoohalike maʻamau i mea hoʻokahi, ʻaʻohe hopena o ka ʻōnaehana o nā hoohalike.
ʻAʻole pono mākou e poina e pili ana i ka Special Theory of Relativity a me nā hopena relativistic me ka hoʻonui ʻana i ka manawa ma nā uaki atomika satellite e pili ana i nā wati honua.
Inā manaʻo mākou e neʻe ana ka satellite i ka orbit ma ka wikiwiki o 14 tausani km / h, a laila loaʻa iā mākou ka manawa dilation ma kahi o 7 μs (microseconds). Ma ka ʻaoʻao ʻē aʻe, hana nā hopena relativistic o ka General Theory of Relativity.
ʻO ke kumu kēia: ʻo nā satelite ma ka orbit ma kahi mamao loa mai ka Honua, kahi i emi iho ai ka curvature o ka continuum space-time ma mua o ka ʻili o ka Honua ma muli o ka nui o ka Honua. Wahi a ka relativity maʻamau, ʻoi aku ka lohi o nā uaki e kokoke ana i kahi mea nui ma mua o nā uaki ma kahi mamao aku.
- ʻO G ka ʻumekaumaha mau;
- ʻO M ka nuipaʻa o ka mea, ma kēia ʻano ka Honua;
- r ka mamao mai ke kikowaena o ka Honua a i ka satellite;
- c ka mama o ka malamalama.
ʻO ka helu ʻana me ka hoʻohana ʻana i kēia kumulāʻau e hāʻawi i ka manawa dilation o 45 μs ma ka satellite. Ka huina -7μs +45μs = 38μs koena - nā hopena o STR a me GTR.
Ma nā noi hoʻonohonoho SRNS, pono e noʻonoʻo ʻia nā lohi ionospheric a me tropospheric. Eia kekahi, ʻo nā hoʻoponopono 46 ns ma muli o ka 0.02 eccentricity o ka orbit GPS satellites.
ʻO ka hiki ke loaʻa nā hōʻailona i ka manawa like mai ʻehā mau GPS / GLONASS satellite e hiki ai iā ʻoe ke hoʻonui hou i ka pololei o ka hoʻoholo ʻana i nā hoʻonohonoho o ka mea hoʻokipa. Loaʻa kēia ma muli o ka hoʻoponopono ʻana o ka mea hoʻokele i kahi ʻōnaehana o nā hoʻohālikelike ʻehā me nā mea ʻike ʻole ʻehā ka helu o nā manawa a lawe i ka waiwai awelika, e hoʻonui ana i ka pololei o ka helu hope e like me nā kānāwai o ka helu makemakika.
Pehea e hoʻonohonoho ai i ka server NTP Stratum 1 ma o ka pilina satellite
No ka hoʻonohonoho ʻana i kahi kikowaena manawa kiʻekiʻe, pono ʻoe i ka GPSD, NTP a me kahi mea hoʻokipa GPS me ka 1PPS (hoʻokahi pulse i kekona).
1. E hoʻouka i ka gpsd a me ka ntpd, a i ʻole ka gpsd a me ka chronyd. Pono ka mana GPSD ≥ 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. Hoʻohui i kahi mea hoʻokipa GPS me ke kākoʻo PPS i ka RS232 serial a i ʻole ke awa USB.
ʻAʻole e holo ka mea hoʻokipa GPS maʻamau; Pono paha ʻoe e ʻimi liʻiliʻi e ʻimi i ka mea kūpono.
3. E hōʻoia i ka hoʻopuka pono ʻana o ka hāmeʻa i ka PPS, no ka hana ʻana i kēia, e nānā i ke awa me ka pono gpsmon.
4. E wehe i ka waihona /etc/conf.d/gpsd a hoʻoponopono i kēia laina.
Hoʻololi
GPSD_OPTIONS=""i lilo ai
GPSD_OPTIONS="-n"Pono kēia hoʻololi i hoʻomaka koke ʻo gpsd e ʻimi i nā kumu SRNS ma ka hoʻomaka ʻana.
5. Hoʻomaka a hoʻomaka hou i ka gpsd.
(1:110)$ sudo /etc/init.d/gpsd start
(1:111)$ sudo /etc/init.d/gpsd restart
No nā māhele me systemd, e hoʻohana i ke kauoha systemctl kūpono.
6. E nānā i ka console output o ke kauoha cgps.
Pono ʻoe e hōʻoia ua loaʻa pololei ka ʻikepili mai nā satelite. Pono ka console e like me ke kiʻi.
Ka puka o ke kauoha cgps console.
7. ʻO ka manawa kēia e hoʻoponopono ai i ka faila /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
Hōʻike ka helu NTP0 kiʻekiʻe i kahi kumu manawa honua i loaʻa ma kahi kokoke i nā polokalamu GPS āpau. ʻO ka helu NTP1 lalo e wehewehe i kahi kumu PPS pololei loa.
8. Hoʻomaka hou i ka ntpd.
(1:112)$ sudo /etc/init.d/ntpd restart
No nā māhele me systemd, e hoʻohana i ke kauoha systemctl.
$ sudo systemctl hoʻomaka hou ntp
Nā mea i hoʻohana ʻia
- David L Mills ʻO ka Pūnaehana Manawa Pūnaewele ma ka Honua a ma Space,Papa Elua.
Source: www.habr.com