Na mgbakwunye na tcp/ip, enwere ọtụtụ ụzọ iji mekọrịta oge. Ụfọdụ n'ime ha chọrọ naanị ekwentị mgbe niile, ebe ndị ọzọ chọrọ ngwa eletrọnịkị dị oke ọnụ, nke na-adịghị ahụkebe na nke nwere mmetụta. Nnukwu akụrụngwa nke sistemu mmekọrịta oge gụnyere ihe nleba anya, ụlọ ọrụ gọọmentị, ụlọ ọrụ redio, igwe kpakpando satịlaịtị na ọtụtụ ndị ọzọ.
Taa, m ga-agwa gị ka ịmekọrịta oge na-arụ ọrụ na-enweghị ịntanetị yana otu esi eji aka gị mee ihe nkesa "satellite" NTP.
Mgbasa ozi redio dị mkpụmkpụ
Na United States, NIST na-ebunye kpọmkwem oge na ugboro ugboro na 2.5, 5, 10, 15 na 20 MHz redio ebili mmiri site na WWVH na Fort Collins, Colorado, na na 2.5, 5, 10 na 15 MHz site na WWVH na Kauai. State nke Hawaii . A na-ebufe koodu oge na nkeji nkeji 60 na 1 bps. na-eji mgbada obosara pulse na ụgbọ ala 100 Hz.
National Research Council (NRC) nke Canada na-ekesa ozi oge na ugboro na 3.33, 7.85 na 14.67 MHz site na CHU na Ottawa, Ontario.
Ọkpụkpọ mgbasa ozi WMVH
Mgbasa mgbaàmà sitere na ọdụ ụgbọ mmiri dị mkpụmkpụ na-emekarị site na ntụgharị uche sitere na elu elu nke ionosphere. Enwere ike ịnata mgbasa ozi n'ebe dị anya, mana oge izizi dị n'usoro nke otu millisekọnd.
Ụkpụrụ NTPv4 dị ugbu a gụnyere ndị ọkwọ ụgbọala ọdịyo maka WWV, WMVH na CHU.
Mgbasa ozi redio Longwave
NIST na-ebufekwa oge na ugboro ugboro n'elu redio ogologo ebili mmiri na 60 kHz site na Boulder, Colorado. Enwere ọdụ ụgbọ mmiri ndị ọzọ na-ebufe akara oge na ebili mmiri dị ogologo.
Oku akara na ebe
Ugboro (kHz)
Ike (kW)
WWVB Fort Collins, Colorado, Njikota Obodo Amerika
60
50
DCF77 Mainflingen, Germany
77.5
30
MSF Rugby, United Kingdom
60>
50
HBG Prangins, Switzerland
75
20
JJY Fukushima, Japan
40
50
JJY Saga, Japan
60
50
Ọdụ ọdụ Ọkọlọtọ Ọdịda Dị ala
A na-ebufe koodu oge na nkeji nkeji iri isii na abụọ na 60 bps, dị ka ọdụ ụgbọ mmiri dị mkpụmkpụ. Ụdị nnyefe data yikwara maka ụkpụrụ abụọ ahụ. Mgbama ahụ na-agbasa site na ala ala nke ionosphere, nke kwụsiri ike ma nwee mgbanwe dị iche iche kwa ụbọchị na elu. N'ihi amụma amụma a nke gburugburu anụ ahụ, izi ezi na-abawanye ruo 1 μs.
Usoro mgbasa ozi WWVB
Satellite gburugburu na-arụ ọrụ geostationary
Na US, NIST na-ebufekwa data ziri ezi na oge na ugboro ugboro na ihe dịka 468 MHz site na Satellites Ọrụ Gọọmenti Geostationary (GOES). Koodu oge na-agbanwe yana ozi ejiri mee ntuli aka nke ihe mmetụta dịpụrụ adịpụ. Ọ nwere nibbles 60 BCD na-ebufe na nkeji iri atọ. Ozi koodu oge yiri ọrụ terrestrial.
Sistemụ nhazi ọkwa ụwa
Ngalaba nchekwa nke United States na-eji GPS maka ịnyagharị ziri ezi na ala, oke osimiri na ikuku. Usoro ahụ na-enye mkpuchi elekere 24 nke ụwa site na iji igwe kpakpando nke satịlaịtị na elekere 12 na-achọ na 55 °.
A na-agbasapụ kpakpando mbụ nke satịlaịtị 24 na satịlaịtị 31 na nhazi dị iche iche nke mere na ọ dịkarịa ala satịlaịtị 6 na-ele anya mgbe niile, na 8 ma ọ bụ karịa satịlaịtị na-ele anya n'ọtụtụ ụwa.
Mba ndị ọzọ na-arụ ọrụ ma ọ bụ na-ahazi ọrụ yiri GPS. Russian GLONASS anọwo na-arụ ọrụ ruo afọ iri na abụọ, na-agụta site na September 2, 2010, mgbe ọnụ ọgụgụ nke satịlaịtị mụbara ruo 26 - a na-etinye ìgwè kpakpando ahụ kpamkpam iji kpuchie ụwa.
Satellites GPS gburugburu ụwa.
A na-akpọ sistemụ satịlaịtị nke European Union Galileo. A tụrụ anya na Galileo ga-amalite ịrụ ọrụ n’afọ 2014 ruo 2016, bụ́ mgbe a ga-ebuba satịlaịtị 30 niile e mere atụmatụ n’ime orbit. Ma n’afọ 2018, ìgwè kpakpando satịlaịtị Galileo erubeghị ọnụ ọgụgụ satịlaịtị a chọrọ.
E nwekwara Chinese "Beidou", nke pụtara "whale". Ejiri igwe satịlaịtị 16 rụọ ọrụ azụmahịa na Disemba 27, 2012, dị ka usoro nhazi mpaghara. A na-eme atụmatụ na usoro a ga-erute ikike zuru oke site na 2020. Naanị taa, m pụtara na Habré , banyere mwepụta nke ọma nke satịlaịtị nke usoro a.
Mathematics nke ikpebi nhazi site na iji SRNS
Kedu otu onye ọkwọ ụgbọ ala GPS/GLONASS dị na ekwentị gị si ekpebi ebe ọ dị n'ụzọ ziri ezi site na iji sistemụ nkwurịta okwu igodo redio (SRNS)? Iji ghọta ụkpụrụ nke mgbako, ịkwesịrị icheta stereometry na algebra na ụlọ akwụkwọ sekọndrị, ma ọ bụ ụlọ akwụkwọ physics na mgbakọ na mwepụ.
Satellite ọ bụla na-agwa onye nnata kpọmkwem oge. Satellite nwere elekere atọm ya mere enwere ike ịtụkwasị obi. N'ịmara ọsọ nke ìhè, ọ naghị esiri ike ịchọpụta radius nke gburugburu n'elu nke satịlaịtị dị. Otu mpaghara a, na kọntaktị na ụwa, na-etolite okirikiri ebe ihe nnata GPS / Glonass dị.
Mgbe mgbaàmà na-abịa site na satịlaịtị abụọ, anyị enweelarị njikọ nke ụwa na akụkụ abụọ, nke na-enye naanị isi abụọ na gburugburu. Mpaghara nke satịlaịtị nke atọ kwesịrị ịdaba n'otu n'ime isi ihe abụọ a, n'ikpeazụ na-ekpebi nhazi nke nnata.
N'ụkpụrụ, ọbụlagodi site na satịlaịtị abụọ, dabere na ihe akaebe na-apụtaghị ìhè, mmadụ nwere ike ịghọta nke n'ime isi ihe abụọ ahụ dị nso na eziokwu ahụ, na algọridim ngwanrọ igodo nke oge a nwere ike ịnagide ọrụ a. Gịnị mere anyị ji chọọ satịlaịtị nke anọ?
Na-ekpebi ebe site na iji kpakpando satịlaịtị.
Ọ dị mfe ịhụ na na foto a dị mma enwere ọtụtụ nuances nke ziri ezi nke ngụkọta oge dabere. Oge nnata bụ ikekwe isi mmalite nke njehie pụtara ìhè. Ka ihe niile wee rụọ ọrụ dịka o kwesịrị, oge nnata GPS / Glonass ga-ejikọta ya na oge satịlaịtị. Na-enweghị nke a, njehie ga-∓ 100 puku km.
Site na usoro maka ọsọ, oge na anya S = v * t anyị na-enweta nha nha maka ịnyefe akara SRNS. Ebe dị anya na satịlaịtị hà nhata ngwaahịa nke ọsọ ọkụ na oge dị iche na satịlaịtị na nnata.
Nke a bụ n'ihi n'eziokwu na ọbụlagodi na mmekọrịta niile gachara, anyị maara oge tpr na onye nata ya na ogo zuru oke. N'etiti ezi oge na tpr, a ga-enwe Δt mgbe niile, n'ihi nke a na-anabata njehie ngụkọta oge. Ya mere ị chọrọ nke anọ satịlaịtị.
Maka nkọwa mgbakọ na mwepụ doro anya maka mkpa satịlaịtị anọ, anyị ga-ewu usoro nha nha.
Iji chọpụta ihe anọ amaghị x, y, z, na Δt, ọnụọgụ nlebanya ga-abụrịrị nha ma ọ bụ karịa karịa ọnụọgụ amaghị ama. Nke a bụ ọnọdụ dị mkpa mana ezughị oke. Ọ bụrụ na matriks nke nha anya nkịtị tụgharịrị bụrụ otu, usoro nha anya agaghị enwe ihe ngwọta.
Anyị ekwesịghị ichefu banyere Pụrụ iche Theory of Relativity na relativistic mmetụta na oge dilation na satịlaịtị atom clocks ikwu na ala ndị.
Ọ bụrụ na anyị na-eche na satịlaịtị na-agagharị na orbit na ọsọ nke 14 puku km / h, mgbe ahụ, anyị na-enweta nkwụsị oge nke ihe dịka 7 μs (microseconds). N'aka nke ọzọ, mmetụta relativistic nke General Theory of Relativity na-arụ ọrụ.
Isi ihe bụ nke a: Satellites na orbit dị n'ebe dị anya site na Ụwa, ebe ntụgharị nke oge-oge na-aga n'ihu na-erughị n'elu ụwa n'ihi oke ụwa. Dabere na ntule n'ozuzu, elekere dị nso na nnukwu ihe ga-apụta nwayọ karịa nke dịpụrụ adịpụ site na ya.
- G bụ ike ndọda mgbe niile;
- M bụ uka nke ihe, na nke a Ụwa;
- r bụ ebe dị anya site na etiti ụwa ruo na satịlaịtị;
- c bụ ọsọ nke ìhè.
Mgbakọ na-eji usoro a na-enye mgbasawanye oge nke 45 μs na satịlaịtị. Ngụkọta -7μs +45μs = 38μs itule - mmetụta nke STR na GTR.
Na ngwa ntinye SRNS, ionospheric na tropospheric na-egbu oge kwesịrị iburu n'uche. Na mgbakwunye, mmezi 46 ns bụ n'ihi 0.02 eccentricity nke satịlaịtị GPS 'orbit.
Ikike ịnata akara n'otu oge site na satịlaịtị GPS / GLONASS anọ na-enye gị ohere ịbawanye izi ezi nke ikpebi nhazi nke nnata. A na-enweta nke a n'ihi na onye na-akwọ ụgbọ mmiri na-edozi usoro nke nha anọ na anọ amaghị ọnụ ọgụgụ nke ugboro na-ewe nkezi uru, na-amụba izi ezi nke ikpeazụ atụmatụ dị ka iwu nke mgbakọ na mwepụ ọnụ ọgụgụ.
Otu esi ahazi sava NTP Stratum 1 site na njikọ satịlaịtị
Ka ịtọlite sava oge dị elu, ị ga-achọ naanị GPSD, NTP na ihe nnata GPS nwere mmepụta 1PPS (otu pulse kwa sekọnd).
1. Wụnye gpsd na ntpd, ma ọ bụ gpsd na chronyd. Ụdị GPSD ga-abụrịrị ≥ 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. Jikọọ ihe nnata GPS nwere nkwado PPS na RS232 serial ma ọ bụ ọdụ ụgbọ USB.
Nnata GPS dị ọnụ ala mgbe niile agaghị arụ ọrụ; Ị nwere ike ime ntakịrị nyocha iji chọta nke ziri ezi.
3. Jide n'aka na ngwaọrụ ahụ na-enye PPS n'ezie; iji mee nke a, lelee ọdụ ụgbọ mmiri site na iji gpmon utility.
4. Mepee faịlụ /etc/conf.d/gpsd ma dezie ahịrị na-esonụ.
Dochie
GPSD_OPTIONS=""nke mere na ọ na-aghọ
GPSD_OPTIONS="-n"Achọrọ mgbanwe a ka gpsd malite ozugbo ịchọ isi mmalite SRNS mgbe mmalite.
5. Malite ma ọ bụ malitegharịa gpsd.
(1:110)$ sudo /etc/init.d/gpsd start
(1:111)$ sudo /etc/init.d/gpsd restart
Maka nkesa nwere sistemu, jiri iwu systemctl dabara adaba.
6. Lelee mmepụta njikwa nke iwu cgps.
Ịkwesịrị ijide n'aka na enwetara data ahụ nke ọma site na satịlaịtị. Ihe njikwa kwesịrị inwe ihe yiri ihe atụ a.
Mpụta nke iwu cgps console.
7. Ọ bụ oge dezie /etc/ntp.conf faịlụ.
# 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
Ntinye NTP0 kacha elu na-egosi isi mmalite oge zuru ụwa ọnụ dị na ihe fọrọ nke nta ka ọ bụrụ ngwaọrụ GPS niile. Ntinye NTP1 nke ala na-akọwapụta isi mmalite PPS ziri ezi karịa.
8. Malitegharịa ekwentị ntpd.
(1:112)$ sudo /etc/init.d/ntpd restart
Maka nkesa nwere sistemu, jiri iwu systemctl.
$ sudo systemctl malitegharịa ntp
Ihe eji eme ihe
- David L Mills Usoro oge netwọkụ na ụwa na oghere, Mbipụta nke Abụọ.
isi: www.habr.com