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australia:gps

global positioning system (GPS) / global navigation satellite systems (GNSS)

Introduction

  • global navigation satellite systems (GNSS) that provide geolocation and time information to a GNSS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more atomic clock GNSS satellites which are generally in medium orbit (hence are MEO satellites) (ie. not Low Earth Orbiting (LEO) satellites like Starlink or Iridium)
    • does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of the satellite positioning information
  • GNSS is a positioning, navigation, and timing (PNT) solution which can be supplemented by other systems such as LEO satellite time and location services (eg. Iridium)
  • the official “GPS” is the US Military controlled satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31.
  • new GNSS have been developed by other countries such as China's BeiDou (BDS), Russia's Global Navigation Satellite System (GLONASS), and the European Union's Galileo
    • these have been developed largely to avoid being at the mercy of a US military controlled system which could be used against them and which could be turned off at a moment's notice
    • hence in 2025 after US attacked Iran, and Iran accused Meta and its Whatsapp messenging service for providing GPS coordinates of its scientists and military leaders to the Israel intelligence as well as the US being able to track it's ships and other vehicles which use US GPS for navigation, Iran is moving to China's potentially superior BeiDou system.
  • in addition, two regional systems are operational: India's NavIC and Japan's QZSS
  • civil equipment like our phones, cannot choose which navigation system to use - it will automatically pick the system that has best signal at that time if it is enabled for that system
    • Samsung devices and Apple iPhones can use BeiDou's services and presumably BeiDou could track you unlike other GNSS systems (see below)

LEO satellites vs GNSS satellites

  • Low Earth Orbiting (LEO) satellites like Starlink or Iridium are NOT designed to provide accurate GNSS but to provide ~1000x stronger signal strength which allows for satellite phone functionality and/or broadband internet functionality with much better ability to penetrate structures for much better indoor reception and much higher data bandwidths
  • GNSS satellites are normally orbiting earth at 12,550 miles above earth with a more predictable orbit with much less atmospheric drag - that is, GNSS satellites are 25x further away than LEO satellites which are at 485 miles above earth
  • GNSS satellites have highly accurate atomic clocks - this accuracy is necessary for accurate GNSS functionality - LEO satellites generally do not have these
  • GNSS satellites also have wider range of global ground-based infrastructure with a large number of receivers and supporting systems
  • the commercial Starlink LEO satellites are not designed to provide GNSS signals but instead are designed for broadband internet access
    • allegedly Musk and SpaceX do not want distractions which may impact profitability of Starlink and has declined offers to add GNSS
      • Nevertheless, it seems that by reverse-engineering the StarLink satellite signals, it may be possible to create a GNSS without support from SpaceX 1)
      • one might also ponder whether Musk et al, have actually embedded GNSS functionality in Starlink (it would need sufficiently accurate clocks) and are able to enable it if needed in case US GPS goes down or it is needed for military purposes in the future such as covert, independent control of mobile AI robots or autonomous vehicles
  • the commercial Iridium LEO satellite system does not have GNSS functionality but does offer a complementary service called Iridium Satellite Time and Location (Iridium STL) which enhances the resiliency and reliability of GNSS signals for critical infrastructure
    • they can also be used to detect and mitigate GNSS interference
    • Iridium STL was built to address vulnerabilities and limitations faced by GPS and GNSS—with a time and location capability that secures PNT-dependent applications against disruption and manipulation.
      • as it is from a LEO satellite system, the Iridium STL signal is about 1,000 times stronger than GPS or GNSS
      • it is the only LEO-based PNT solution commercially available worldwide.
  • other LEO satellite systems:
    • Globalstar - partnered with Apple for emergency SOS txts
    • Eutelsat OneWeb
    • Amazon's Project Kuiper

the US GPS

  • GPS is owned by the United States Space Force and operated by Mission Delta 31.
    • The U.S. Department of Defense is required by law to “maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis” and “develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses”.
  • 1957: when Russia launched its Sputnik 1 in 1957 and it was noted that because of the Doppler effect, they could pinpoint where the satellite was along its orbit and then worked out the reverse - pinpointing a user's location, given the satellite's location.
  • 1959-1960: this led the US to develop ARPA in 1959, TRANSIT in 1960 - this used a constellation of five satellites and could provide a navigational fix approximately once per hour.
  • 1964, the United States Army orbited its first Sequential Collation of Range (SECOR) satellite used for geodetic surveying. The SECOR system included three ground-based transmitters at known locations that would send signals to the satellite transponder in orbit. A fourth ground-based station, at an undetermined position, could then use those signals to fix its location precisely. The last SECOR satellite was launched in 1969.
  • 1967, the U.S. Navy developed the Timation satellite, which proved the feasibility of placing accurate clocks in space, a technology required for GPS.
  • early 1970s, the ground-based OMEGA navigation system, based on phase comparison of signal transmission from pairs of stations,[27] became the first worldwide radio navigation system.
  • nuclear concerns of the cold war and the need for accurate location data for the United States Navy's submarine-launched ballistic missiles (SLBMs) provided impetus for US Congress funding of the development of the GPS.
  • 1973, critical satellite orbital position errors, induced by variations in the gravity field and radar refraction, etc were resolved and plans developed to launch 10 new “Block 1” Navstar-GPS satellites
  • 1978-1985: 10 launches of Block I GPS satellites (none currently active)
  • 1983: US President Ronald Reagan allows a degraded version of the GPS to be used by civilians after a Korean passenger plane accidentally entered Soviet air space and was shot down in 1983.
  • 1989-1997: The first Block II GPS satellite was launched in Feb 1989 and the 24th satellite was launched in 1994. This had cost $US5b ($US11b in 2024 money). None of these are currently active.
  • 1989: Garmin, a US sat-nav manufacturer was founded after recruiting Min H. Kao from the defense contractor Magnavox - their first product was a GPS unit for boaters released in 1990 called ProNav GPS 100. In 1991, it opened a manufacturing facility in Taiwan and the US Army became its 1st major customer.
  • 1990-91: first conflict in which the military widely used GPS - the Gulf War
  • 1991: DARPA's project to create a miniature GPS receiver successfully ended, replacing the previous 16 kg (35 lb) military receivers with a 1.25 kg (2.8 lb) all-digital handheld GPS receiver
  • 1991: TomTom, a Dutch sat-nav manufacturer was founded
  • 1993: GPS achieved initial operational capability (IOC), with a full constellation (24 satellites) available and providing the Standard Positioning Service (SPS)
  • 1995: Full Operational Capability (FOC) was declared by Air Force Space Command (AFSPC) in April 1995, signifying full availability of the military's secure Precise Positioning Service (PPS)
  • 1996: U.S. President Bill Clinton issued a policy directive declaring GPS a dual-use system (military and civilian) and establishing an Interagency GPS Executive Board to manage it as a national asset.
  • 1997-2004: 12 launches of Block IIR GPS satellites (7 active)
  • 1998: StreetPilot was Garmin’s first portable navigation system for cars
  • 2000: in response to widespread growth of differential GPS services by private industry to improve civilian accuracy, May 1, 2000, with U.S. President Bill Clinton signs a policy directive to turn off Selective Availability to provide the same accuracy to civilians that was afforded to the military.
  • 2004: the National Space-Based Positioning, Navigation and Timing Executive Committee was established by presidential directive to advise and coordinate federal departments and agencies on matters concerning the GPS and related systems
  • 2004: the US government signed an agreement with the European Community establishing cooperation related to GPS and Europe's Galileo system.
  • 2004: Qualcomm announced successful tests of assisted GPS for mobile phones
  • 2005-2009: 8 launches of Block IIR-M GPS satellites (7 active)
    • 2005, the first modernized GPS satellite was launched and began transmitting a second civilian signal (L2C) for enhanced user performance
  • 2008: 1st Apple iPhone released with GPS embedded (albeit with degraded location accuracy of 10m) - the iPhone 3G which also was the 1st to have 3G mobile connectivity (the 1st iPhone was released in 2007)
  • 2010-2016: 12 launches of Block IIF GPS satellites (11 active)
  • 2011: Garmin released its first GPS watch
  • 2015: high-quality Standard Positioning Service (SPS) GPS receivers provided horizontal accuracy of better than 3.5 meters
  • 2018 onwards: 6 launches of Block IIIA GPS satellites
  • 2020: operation of the GPS constellation is transferred to the newly established U.S. Space Force as part of its establishment
  • 2023: the Space Force activated PNT Delta (Provisional) to manage US navigation warfare assets. 2SOPS and GPS operations were realigned under this new Delta.

Russia's Global Navigation Satellite System (GLONASS)

  • transmit two types of signals: open standard-precision signal L1OF/L2OF giving 5-10m precision, and an obfuscated high-precision signal L1SF/L2SF for Russian military use only
    • signals use similar DSSS encoding and binary phase-shift keying (BPSK) modulation as in GPS signals
  • higher orbital inclination (64.8°) than US GPS, improves positioning in high latitudes (near the poles)
  • the precise location of the North Pole is given as an average of its position from 1990 to 1995. This is in contrast to the US GPS's coordinate datum, WGS 84, which uses the location of the North Pole in 1984.
  • operates in three orbital planes, with eight evenly spaced satellites on each
  • 18 satellites are necessary for covering the territory of Russia, additional 6 for global coverage
  • to get a position fix the receiver must be in the range of at least four satellites
  • 1976: development of GLONASS begins
  • 1982-1995: numerous rocket launches added satellites to the system until the completion of the constellation in 1995
  • 2010: GLONASS achieved full coverage of Russia's territory
  • 2011: the full orbital constellation of 24 satellites was restored, enabling full global coverage.
  • 2023: new satellite design, GLONASS-K2, launched

European Union's Galileo

  • created by the European Union through the European Space Agency (ESA) and operated by the European Union Agency for the Space Programme (EUSPA) and intended primarily for civilian use
  • headquartered in Prague, Czechia, with two ground operations centres in Oberpfaffenhofen, Germany (mostly responsible for the control of the satellites), and in Fucino, Italy (mostly responsible for providing the navigation data)
  • one of the aims of Galileo is to provide an independent high-precision positioning system so European political and military authorities do not have to rely on the United States GPS or the Russian GLONASS systems, which could be disabled or degraded by their operators at any time
  • it is also to provide a new global search and rescue (SAR) function as part of the MEOSAR system
  • 2003: China joined the Galileo project
  • 2004: Israel joins the Galileo project
  • 2004: the US forced them to reach the compromise that Galileo is to use different frequencies to US GPS. This allows the blocking or jamming of either GNSS without affecting the other. The frequency initially chosen for Galileo would have made it impossible for the US to block the Galileo signals without also interfering with its own GPS signals.
  • 2005: Ukraine, Morocco and India join the Galileo project
  • 2005: first Galileo test satellite GIOVE-A was launched
  • 2006: the public-private partnership fell apart, and the European Commission decided to nationalise the Galileo programme
  • 2006, China leaves the Project and opts instead to upgrade its BeiDou navigation system, its then-regional satellite navigation system
  • 2008: a second test satellite, GIOVE-B, was launched
  • 2009, a ground station for Galileo was inaugurated near Kourou (French Guiana)
  • 2011: first two Galileo In-Orbit Validation satellites were launched by Soyuz ST-B flown from Centre Spatial Guyanais
  • 2012: remaining two Galileo In-Orbit Validation satellites were launched
  • 2014-15: first four pairs of satellites with Full Operational Capability (FOC), each with four clocks (2 PHM and 2 RAFS), were launched
  • 2016: began offering limited services “Early Operational Capability (EOC)”
    • use of basic (lower-precision) Galileo services is free and open to everyone
  • 2017: four of the full operational satellites had each lost at least one clock, but all had at least one functional clock left
    • six of the passive hydrogen masers (PHM) and three of the rubidium atomic clocks (RAFS) had failed
  • 2018: four more Galileo satellites were brought online, increasing the number of active satellites to 18
  • 2018: FCC approved use of Galileo in the US
  • 2023: higher-precision service is now available for free
    • has a greater accuracy than US GPS, having an accuracy of less than 1 m when using broadcast ephemeris compared to 3m for US GPS

China's BeiDou system

  • 1994: China commences development of BeiDou when China realised the risk of denied access to GPS during the Yinhe incident and also the benefits to the US in the 1990-91 Gulf War
  • 2000-2012: 1st generation system but provided only regional support
  • 2006, China opted to leave the European Galieo Project and instead to upgrade its BeiDou navigation system, which at that time was only a regional satellite navigation system
  • 2012: 2nd generation system but still only providing regional support for Asia-Pacific region - 16 satellites, including 6 geostationary satellites, 6 inclined geosynchronous orbit satellites, and 4 medium earth orbit satellites
  • 2014, BeiDou became part of the World-Wide Radionavigation System (WWRNS)
  • 2014: Chinese smartphone maker Xiaomi featured BeiDou while Sth Korean Samsung added BeiDou to Galaxy Note 4, Japanese phone maker Sony implemented BeiDou for the first time on their Xperia Z3
  • 2015: system was generating $US31.5b in turnover; 1st launch of a 3rd gen satellite
  • 2018: Taiwan's National Communications Commission announced that it would be illegal to use BeiDou products in Taiwan without its approval as it had concerns of the possibility of embedded malware in BeiDou-enabled hardware and software
  • 2018: the Pakistan Armed Forces received access to BeiDou for military purposes
  • 2019: the Saudi Ministry of Defense signed an agreement for military use of BeiDou
  • 2020: system was generating $US64b in turnover
  • 2020: the 3rd generation system BeiDou-3 became a fully operational global navigation system with added functionality of encrypted SMS text messenging and other features. China is promoting it for its Belt and Road initiative countries. Consists of satellites in three different orbits, including 24 satellites in medium-circle orbits (covering the world), 3 satellites in inclined geosynchronous orbits (covering the Asia-Pacific region), and 3 satellites in geostationary orbits (covering China)
  • 2020: Argentina entered into a cooperation agreement with China regarding the use of BeiDou
  • 2021: the first China-Africa BeiDou System Cooperation Forum was held in Beijing
  • 2021: Apple adds BeiDou to iPhone 13
  • 2022: Vladimir Putin signed an agreement for the interoperability of BeiDou and GLONASS
  • 2025: Iran adopts BeiDou over US GPS in response to military attacks by US-Israel
  • unlike other GNSS which act only as one way beacons, BeiDou also gets user's location data and can also receive SMS texts up to 1200 Chinese characters
    • this could be useful if you need to send your location and message to someone when you are in a remote area HOWEVER, it does open up major tracking and cybersecurity risks
    • normally, if you do not have a Sim card in your phone, and you are not accessing the internet, you are not being tracked, but with BeiDou enabled you could be tracked, especially if malware is in the device's hardware or software - this is part of the reason why Taiwan placed a ban on use of BeiDou in Taiwan, and why many countries have banned Huawei devices, and have concerns about TikTok (Lenovo computers may also be in the same boat but they are generally not banned as yet).
australia/gps.txt · Last modified: 2025/07/10 08:53 by gary1

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