Editing Satellite navigation (section)

==Comparison of systems==
{| class="wikitable" style="text-align:center;"
|-
! System
! [[Beidou Navigation Satellite System|BeiDou]]
! [[Galileo (satellite navigation)|Galileo]]
! [[GLONASS]]
! [[Global Positioning System|GPS]]
! [[Indian Regional Navigation Satellite System|NavIC]]
! [[Quasi-Zenith Satellite System|QZSS]]
|-
! Owner
| [[China]]
| [[EU|European Union]]
| [[Russia]]
| [[United States]]
| [[India]]
| [[Japan]]
|-
! Coverage
| Global
| Global
| Global
| Global
| Regional
| Regional
|-
! [[Channel access method|Coding]]
| [[CDMA]]
| [[CDMA]]
| [[FDMA]] & [[CDMA]]
| [[CDMA]]
| [[CDMA]]
| [[CDMA]]
|-
! Altitude<br />km (mi)
| {{convert|21,150|km|abbr=values|disp=br()}}
| {{convert|23,222|km|abbr=values|disp=br()}}
| {{convert|19,130|km|abbr=values|disp=br()}}
| {{convert|20,180|km|abbr=values|disp=br()}}
| {{convert|36,000|km|abbr=values|disp=br()}}
| {{convert|32,600-39,000|km|abbr=values|disp=br()}}<ref name=h2a>{{cite web |website=NASASpaceFlight.com |url=https://www.nasaspaceflight.com/2017/10/japans-h-2a-rocket-qzss-4-launch/ |title=Japan's H-2A conducts QZSS-4 launch |url-status=live |archive-url=https://web.archive.org/web/20171010005756/https://www.nasaspaceflight.com/2017/10/japans-h-2a-rocket-qzss-4-launch/ |archive-date=2017-10-10 |first1=William |last1=Graham |date=9 October 2017}}</ref>
|-
! Period
| 12.88&nbsp;h<br /> (12&nbsp;h 53&nbsp;min)
| 14.08&nbsp;h<br /> (14&nbsp;h &nbsp;5&nbsp;min)
| 11.26&nbsp;h<br /> (11&nbsp;h 16&nbsp;min)
| 11.97&nbsp;h<br /> (11&nbsp;h 58&nbsp;min)
| 23.93&nbsp;h<br /> (23&nbsp;h 56&nbsp;min)
| 23.93&nbsp;h<br /> (23&nbsp;h 56&nbsp;min)
|-
! Rev./[[sidereal day|S. day]]
| 13/7 {{Gray|(1.86)}}
| 17/10 {{Gray|(1.7)}}
| 17/8 {{Gray|(2.125)}}
| 2
| 1
| 1
|-
! Satellites
| BeiDou-3:<br /> 28 operational<br /> (24 MEO, 3 IGSO, 1 GSO)<br /> 5 in orbit validation<br /> 2 GSO planned 20H1<br />BeiDou-2:<br /> 15 operational<br /> 1 in commissioning 
| By design:
27 operational + 3 spares

Currently:

26 in orbit<br />[[List of Galileo satellites|24 operational]]

2 inactive<br />6 to be launched<ref name="AvWeek12sep2018" />
| 24 by design<br />24 operational<br />1 commissioning<br />1 in flight tests<ref>{{cite web |url= https://www.glonass-iac.ru/en/ |title= Information and Analysis Center for Positioning, Navigation and Timing |access-date= 2018-07-21 |archive-date= 2018-07-21 |archive-url= https://web.archive.org/web/20180721162605/https://www.glonass-iac.ru/en/ |url-status= dead }}</ref>
| 24 by design<br/ >30 operational<ref>{{cite web|url=http://www.gps.gov/systems/gps/space/#generations|title=GPS Space Segment|access-date=2015-07-24}}</ref>
| 8 operational<br />(3 GEO, 5 [[geosynchronous|GSO]] MEO)
| 4 operational (3 GSO, 1 GEO)<br />7 in the future
|-
! Frequency<br />GHz
| 1.561098&nbsp;(B1)<br />1.589742&nbsp;(B1-2)<br />1.20714&nbsp;(B2)<br />1.26852&nbsp;(B3)
| 1.559–1.592 (E1)<br>1.164–1.215 (E5a/b)<br />1.260–1.300 (E6)
| 1.593–1.610 (G1)<br />1.237–1.254 (G2)<br>1.189–1.214 (G3)
| 1.563–1.587 (L1)<br />1.215–1.2396 (L2)<br>1.164–1.189 (L5)
| 1.57542 (L1)<br />1.17645 (L5)<br />2.49202 (S)
| 1.57542 (L1C/A, L1C, L1S)<br />1.22760 (L2C)<br />1.17645 (L5, L5S)<br />1.27875 (L6)<ref>{{cite web |url= https://qzss.go.jp/overview/services/sv03_signals.html |title=送信信号一覧 |access-date=2019-10-25}}</ref>
|-
! Status
| Operational<ref name="bdsStatus20200623">{{Cite web|url=https://phys.org/news/2020-06-china-satellite-gps-like-beidou.html|title=China launches final satellite in GPS-like Beidou system|publisher=phys.org|access-date=24 June 2020|archive-url=https://web.archive.org/web/20200624080233/https://phys.org/news/2020-06-china-satellite-gps-like-beidou.html|archive-date=24 June 2020|url-status=live}}</ref>
| Operating since 2016<br />2020 completion<ref name=AvWeek12sep2018>{{cite news  |url= http://aviationweek.com/world-satellite-business-week/rise-new-navigation-satellites |url-access=subscription |title= The Rise Of New Navigation Satellites |date= Sep 12, 2018 |author1=Irene Klotz |author2=Tony Osborne |author3=Bradley Perrett |work= Aviation Week Network |url-status=live |archive-url=https://web.archive.org/web/20231025102726/https://aviationweek.com/defense-space/space/rise-new-navigation-satellites |archive-date=Oct 25, 2023 }}</ref>
| Operational
| Operational
| Operational
| Operational
|-
! Accuracy<br />m (ft)
| {{convert|3.6|m|ft|abbr=values}} (public)<br />{{convert|0.1|m|ft|abbr=values}} (encrypted)
| {{convert|0.2|m|ft|abbr=values}} (public)<br />{{convert|0.01|m|ft|abbr=values}} (encrypted)
| {{convert|2|-|4|m|ft|abbr=values}}
| {{convert|0.3|-|5|m|ft|abbr=values}}<br>(no DGPS or WAAS)
| {{convert|1|m|ft|abbr=values}} (public)<br />{{convert|0.1|m|ft|abbr=values}} (encrypted)
| {{convert|1|m|ft|abbr=values}} (public)<br />{{convert|0.1|m|ft|abbr=values}} (encrypted)

|-
! System
! [[Beidou Navigation Satellite System|BeiDou]]
! [[Galileo (satellite navigation)|Galileo]]
! [[GLONASS]]
! [[Global Positioning System|GPS]]
! [[Indian Regional Navigation Satellite System|NavIC]]
! [[Quasi-Zenith Satellite System|QZSS]]
|-
| colspan=7 | Sources:<ref name="autogenerated3"/><ref>{{Cite book |last1=Aswal |first1=Dinesh K. |url=https://books.google.com/books?id=I73SEAAAQBAJ&pg=PA512 |title=Handbook of Metrology and Applications |last2=Yadav |first2=Sanjay |last3=Takatsuji |first3=Toshiyuki |last4=Rachakonda |first4=Prem |last5=Kumar |first5=Harish |date=2023-08-23 |publisher=Springer Nature |isbn=978-981-99-2074-7 |pages=512 |language=en}}</ref><ref>{{Cite web |date=August 2023 |title=NAVIC SIGNAL IN SPACE ICD FOR STANDARD POSITIONING SERVICE IN L1 FREQUENCY |url=https://www.isro.gov.in/media_isro/pdf/SateliteNavigation/NavIC_SPS_ICD_L1_final.pdf |access-date=20 September 2024 |website=ISRO}}</ref>
|}

Using multiple GNSS systems for user positioning increases the number of visible satellites, improves precise point positioning (PPP) and shortens the average convergence time.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S0273117718304745 | doi=10.1016/j.asr.2018.06.008 | title=Assessing the latest performance of Galileo-only PPP and the contribution of Galileo to Multi-GNSS PPP | year=2019 | last1=Xia | first1=Fengyu | last2=Ye | first2=Shirong | last3=Xia | first3=Pengfei | last4=Zhao | first4=Lewen | last5=Jiang | first5=Nana | last6=Chen | first6=Dezhong | last7=Hu | first7=Guangbao | journal=Advances in Space Research | volume=63 | issue=9 | pages=2784–2795 | bibcode=2019AdSpR..63.2784X | s2cid=125213815 | url-access=subscription }}</ref>
The signal-in-space ranging error (SISRE) in November 2019 were 1.6&nbsp;cm for Galileo, 2.3&nbsp;cm for GPS, 5.2&nbsp;cm for GLONASS and 5.5&nbsp;cm for BeiDou when using real-time corrections for satellite orbits and clocks.<ref>{{cite journal |last1=Kazmierski |first1=Kamil |last2=Zajdel |first2=Radoslaw |last3=Sośnica |first3=Krzysztof |title=Evolution of orbit and clock quality for real-time multi-GNSS solutions |journal=GPS Solutions |year=2020 |volume=24 |issue=111 |page=111 |doi=10.1007/s10291-020-01026-6 |bibcode=2020GPSS...24..111K |doi-access=free}}</ref> The average SISREs of the BDS-3 MEO, IGSO, and GEO satellites were 0.52 m, 0.90 m and 1.15 m, respectively. Compared to the four major global satellite navigation systems consisting of MEO satellites, the SISRE of the BDS-3 MEO satellites was slightly inferior to 0.4 m of Galileo, slightly superior to 0.59 m of GPS, and remarkably superior to 2.33 m of GLONASS. The SISRE of BDS-3 IGSO was 0.90 m, which was on par with the 0.92 m of QZSS IGSO. However, as the BDS-3 GEO satellites were newly launched and not completely functioning in orbit, their average SISRE was marginally worse than the 0.91 m of the QZSS GEO satellites.<ref name=":1" />