Satellite navigation device
A satellite navigation device, satnav device or satellite navigation receiver is a user equipment that uses one or more of several
As of 2023[update], four GNSS systems are operational: the original United States'
A satellite navigation device can retrieve location and time information from one or more GNSS systems in all weather conditions, anywhere on or near the Earth's surface. Satnav reception requires an unobstructed line of sight to four or more GNSS satellites,
An automotive navigation system takes its location from a GNSS system and, depending on the installed software, may offer the following services:
- Mapping, including street maps, text or in a graphical format,
- Turn-by-turn navigation directions via text or speech,
- Directions fed directly to a self-driving car,
- Traffic congestion maps, historical or real-time data, and suggested alternative directions,
- Information on nearby amenities such as restaurants, fueling stations, and tourist attractions,
- Alternative routes.
History
As with many other technological breakthroughs of the latter 20th century, the modern GNSS system can reasonably be argued to be a direct outcome of the Cold War of the latter 20th century. The multibillion-dollar[citation needed] expense of the US and Russian programs was initially justified by military interest. In contrast, the European Galileo was conceived as purely civilian.
In 1960, the US Navy put into service its Transit satellite-based navigation system to aid in naval navigation. The US Navy in the mid-1960s conducted an experiment to track a submarine with missiles with six satellites and orbiting poles and was able to observe satellite changes.[4] Between 1960 and 1982, as the benefits were shown, the US military consistently improved and refined its satellite navigation technology and satellite system. In 1973, the US military began to plan for a comprehensive worldwide navigational system which eventually became known as the GPS (Global Positioning System).
In 1983, in the wake of the tragedy of the downing of
In 1989, Magellan Navigation Inc. unveiled its Magellan NAV 1000, the world's first commercial handheld GPS receiver. These units initially sold for approximately US$2,900 each. In 1990,
As GNSS navigation systems became more and more widespread and popular, the pricing of such systems began to fall, and their widespread availability steadily increased. Several additional manufacturers of these systems, such as Garmin (1991), Benefon (1999), Mio (2002) and TomTom (2002) entered the market. Mitac Mio 168 was the first PocketPC to contain a built-in GPS receiver.[10] Benefon's 1999 entry into the market also presented users with the world's first phone based GPS navigation system. Later, as smartphone technology developed, a GPS chip eventually became standard equipment for most smartphones. To date, ever more popular satellite navigation systems and devices continue to proliferate with newly developed software and hardware applications. It has been incorporated, for example, into cameras.
While the American GPS was the first satellite navigation system to be deployed on a fully global scale, and to be made available for commercial use, this is not the only system of its type. Due to military and other concerns, similar global or regional systems have been, or will soon be deployed by Russia, the European Union, China, India, and Japan.
Sensitivity
GNSS devices vary in sensitivity, speed, vulnerability to multipath propagation, and other performance parameters. High-sensitivity receivers use large banks of correlators[clarification needed][citation needed] and digital signal processing to search for signals very quickly. This results in very fast times to first fix when the signals are at their normal levels, for example, outdoors. When signals are weak, for example, indoors, the extra processing power can be used to integrate weak signals to the point where they can be used to provide a position or timing solution.
GNSS signals are already very weak when they arrive at the Earth's surface. The
Conventional GPS receivers integrate the received GPS signals for the same amount of time as the duration of a complete C/A code cycle which is 1 ms. This results in the ability to acquire and track signals down to around the −160 dBW level. High-sensitivity GPS receivers are able to integrate the incoming signals for up to 1,000 times longer than this and therefore acquire signals up to 1,000 times weaker, resulting in an integration gain of 30 dB. A good high-sensitivity GPS receiver can acquire signals down to −185 dBW, and tracking can be continued down to levels approaching −190 dBW.
High-sensitivity GPS can provide positioning in many but not all indoor locations. Signals are either heavily attenuated by the building materials or reflected as in multipath. Given that high-sensitivity GPS receivers may be up to 30 dB more sensitive, this is sufficient to track through 3 layers of dry bricks, or up to 20 cm (8 inches) of steel-reinforced concrete, for example.[citation needed]
Examples of high-sensitivity receiver chips include SiRFstarIII and MediaTekʼs MTK II.[11]
Consumer applications
Consumer GNSS navigation devices include:
- Dedicated GNSS navigation devices
- modules that need to be connected to a computer to be used
- loggers that record trip information for download. Such geocoded photographs.
- Converged devices, including Satnav phones and planned wireless data servicesis controversial.
Dedicated devices have various degrees of mobility. Hand-held, outdoor, or sport receivers have replaceable batteries that can run them for several hours, making them suitable for
Other receivers, often called mobile are intended primarily for use in a car, but have a small rechargeable internal battery that can power them for an hour or two[
The pre-installed embedded software of early receivers did not display maps; 21st-century ones commonly show interactive street maps (of certain regions) that may also show
Manufacturers include:
- Navman products
- TomTom products
- Garmin products
- Mio products
- Navigon products
- Magellan Navigation consumer products
- Satmap Systems Ltd
- TeleType products
Integration into smartphones
Almost all smartphones now incorporate GNSS receivers[citation needed]. This has been driven both by consumer demand and by service suppliers. There are now many phone apps that depend on location services, such as navigational aids, and multiple commercial opportunities, such as localised advertising. In its early development, access to user location services was driven by European and American emergency services to help locate callers.[13]
All smartphone operating systems offer
The use of mobile phones as navigational devices has outstripped the use of standalone GNSS devices. In 2009, independent analyst firm Berg Insight found that GNSS-enabled GSM/WCDMA handsets in the USA alone numbered 150 million units,[14] against the sale of only 40 million standalone GNSS receivers.[15]
Some, older,
By tethering to a laptop, some phones can provide localisation services to a laptop as well.[17]
Palm, pocket and laptop PC
Software companies have made available
Palms[19] and Pocket PC's can also be equipped with GPS navigation.[20] A pocket PC differs from a dedicated navigation device as it has an own operating system and can also run other applications.
GPS modules
Other GPS devices need to be connected to a computer in order to work. This computer can be a
Devices usually do not come with pre-installed
Some hobbyists have also made some Satnav devices and open-sourced the plans. Examples include the Elektor GPS units.[23][24] These are based around a SiRFstarIII chip and are comparable to their commercial counterparts. Other chips and software implementations are also available.[25]
Aviators
Military
Military applications include devices similar to consumer sport products for foot soldiers (commanders and regular soldiers), small vehicles and ships, and devices similar to commercial aviation applications for aircraft and missiles. Examples are the United States military's Commander's Digital Assistant and the Soldier Digital Assistant.[27][28][29][30] Prior to May 2000 only the military had access to the full accuracy of GPS. Consumer devices were restricted by selective availability (SA), which was scheduled to be phased out but was removed abruptly by President Clinton.[31] Differential GPS is a method of cancelling out the error of SA and improving GPS accuracy, and has been routinely available in commercial applications such as for golf carts.[32] GPS is limited to about 15 meter accuracy even without SA. DGPS can be within a few centimeters.[33]
Sequential receivers
A sequential GPS receiver tracks the necessary satellites by typically using one or two hardware channels.[34] The set will track one satellite at a time, time tag the measurements and combine them when all four satellite pseudoranges have been measured. These receivers are among the least expensive available, but they cannot operate under high dynamics and have the slowest time-to-first-fix (TTFF) performance.
GPS maps and directions are occasionally imprecise.[citation needed] Some people have gotten lost by asking for the shortest route, like a couple in the United States who were looking for the shortest route from South Oregon to Jackpot, Nevada.[35]
In August 2009 a young mother and her six-year-old son became stranded in Death Valley after following Satnav directions that led her up an unpaved dead-end road. When they were found five days later, her son had died from the effects of heat and dehydration.[36]
In May 2012, Japanese tourists in Australia were stranded when traveling to North Stradbroke Island and their satnav instructed them to drive into Moreton Bay.[37]
In 2008 Satnav routed a softball team bus into a 9 ft tunnel, which sliced off the top of the bus and hospitalized the whole team.[38]
Brad Preston, Oregon claims that people are routed into his driveway five to eight times a week because their Satnav shows a street through his property.[38]
John and Starry Rhodes, a couple from Reno, Nevada were driving home from Oregon when they started to see there was a lot of snow in the area but decided to keep going because they were already 30 miles down the road. But the Satnav led them to a road in the Oregon forest that was not plowed and they were stuck for 3 days.[38]
Mary Davis was driving in an unfamiliar place when her Satnav told her to make a right turn onto a train track while there was a train coming down. Mary was lucky there was a local police officer who noticed the situation and urged her quickly to get out of the car as fast as she could. Mary was lucky enough to get out of the car leaving it for the train to hit and total it. The officer commented that there was a very good chance that they could have had a fatality on their hands.[38]
Other hazards involve an alley being listed as a street, a lane being identified as a road,[39] or rail tracks as a road.[40]
Obsolete maps sometimes cause the unit to lead a user on an indirect, time-wasting route, because roads may change over time. Smartphone Satnav information is usually updated automatically, and free of additional charge. Manufacturers of separate Satnav devices also offer map update services for their merchandise, usually for a fee.
Privacy concerns
User privacy may be compromised if Satnav equipped handheld devices such as mobile phones upload user geo-location data through associated software installed on the device. User geo-location is currently the basis for navigational apps such as Google Maps, location-based advertising, which can promote nearby shops and may allow an advertising agency to track user movements and habits for future use. Regulatory bodies differ between countries regarding the treatment of geo-location data as privileged or not. Privileged data cannot be stored, or otherwise used, without the user's consent.[41]
Vehicle tracking systems allow employers to track their employees' location raising questions regarding violation of employee privacy. There are cases where employers continued to collect geo-location data when an employee was off duty in private time.[42]
See also
- Comparison of web map services
- Dashcam
- Defense Advanced GPS Receiver
- Head unit
- GPS watch
- Precision Lightweight GPS Receiver
- Radio clock
- Turn-by-turn navigation
References
- ^ "Russia Launches Three More GLONASS-M Space Vehicles". Inside GNSS. Archived from the original on 6 February 2009. Retrieved 26 December 2008.
- ^ "index.php". clove.co.uk. 10 January 2012. Archived from the original on 10 March 2016. Retrieved 3 April 2018.
- ^ "What is a GPS?". Library of Congress. Archived from the original on 31 January 2018. Retrieved 29 December 2017.
- ^ Mai, Thuy (7 August 2017). "Global Positioning System History". NASA. Archived from the original on 27 July 2019. Retrieved 11 April 2019.
- S2CID 119545597.
- ^ "Macrometer V-1000". National Museum of American History. 1 January 2010. Archived from the original on 15 May 2021. Retrieved 15 May 2021.
- ^ "1993 Eunos/Mazda Cosmo Classic Drive Uncosmopolitan: Meet the rarest Mazda in America". Motor Trend. TEN: The Enthusiast Network. February 2012. Archived from the original on 5 September 2015. Retrieved 18 January 2015.
- ^ Sigma Heart (16 January 2015). "Mitsubishi DEBONAIR Commercial 1991 Japan". Archived from the original on 27 February 2020. Retrieved 3 April 2018 – via YouTube.
- ^ "Autoradio GPS Android pas cher, Caméra radar de recul - Player Top". www.player-top.fr. Archived from the original on 14 March 2016. Retrieved 18 July 2016.
- ^ Griffin, Darren. "Mitac Mio 168 Review". www.pocketgpsworld.com. Archived from the original on 5 March 2016. Retrieved 3 April 2018.
- ^ US Patent 6674401, McBurney, Paul W.; Woo, Arthur N., "High sensitivity GPS receiver and reception", published 21 August 2003, issued 6 January 2004
- ^ "nüvi® 3500-Serie" (PDF) (User manual). Garmin. Archived (PDF) from the original on 26 June 2021. Retrieved 16 March 2021.
- ^ "Smartphone Offline Navigation Software". poi-factory.com. Archived from the original on 7 April 2014. Retrieved 5 April 2014.
- ^ "GPS and Mobile Handsets – 4th edition" (PDF). Archived from the original (PDF) on 7 July 2011. Retrieved 1 February 2012.
- ^ Kevin J. O'Brien, New York Times, 15 November 2010 Archived 7 November 2017 at the Wayback Machine Smartphone Sales Taking Toll on G.P.S. Devices
- ^ Extended Prediction Orbit Archived 1 July 2013 at the Wayback Machine GPS data logger software
- ^ "Sony Ericsson - Mobile Broadband - Overview - EC400g". 2 April 2015. Archived from the original on 2 April 2015. Retrieved 3 April 2018.
- ^ "List of laptop GPS navigation software programs and reviews". Laptopgpsworld.com. 27 July 2008. Archived from the original on 4 June 2011. Retrieved 1 February 2012.
- ^ Dale DePriest. "Navigation with Palm OS". gpsinformation.org. Archived from the original on 28 March 2014. Retrieved 5 April 2014.
- ^ "GPS Navigation with the GPS Software". force9.co.uk. Archived from the original on 13 April 2014. Retrieved 5 April 2014.
- ^ "PCMCIA GPS adaptors". 5 June 2008. Archived from the original on 5 June 2008. Retrieved 1 February 2012.
- ^ "Sony Ericsson - Mobile Broadband - Overview - EC400g". 8 January 2009. Archived from the original on 8 January 2009. Retrieved 3 April 2018.
- ^ "Multi-purpose GPS Receiver (link1)". Elektor International Media BV. 1 October 2008. Archived from the original on 7 April 2014.
- ^ "Multi-purpose GPS Receiver (link2)". ELEKTOR INTERNATIONAL MEDIA BV. 1 October 2008. Archived from the original on 16 July 2016. Retrieved 16 July 2016.
- ^ "GNSS-SDR, an open source Global Navigation Satellite Systems software defined receiver". Centre Tecnològic de Telecomunicacions de Catalunya (CTTC). 2015. Archived from the original on 14 September 2012.
- ^ U.S. Air Force (3 October 2018). "Aviation". GPS.gov. National Coordination Office for Space-Based Positioning, Navigation, and Timing. Archived from the original on 26 March 2019. Retrieved 11 April 2019.
- ^ "Commanders Digital Assistant explanation and photo" (PDF). 1 December 2007. Archived from the original (PDF) on 1 December 2007. Retrieved 1 February 2012.
- ^ "Latest version Commanders Digital Assistant" (PDF). Archived from the original (PDF) on 1 October 2008. Retrieved 4 October 2016.
- ^ "Soldier Digital Assistant explanation and photo". 10 June 2008. Archived from the original on 10 June 2008. Retrieved 1 February 2012.
- ^ Sinha, Vandana (24 July 2003). "Commanders and Soldiers' GPS receivers". Gcn.com. Archived from the original on 21 September 2009. Retrieved 1 February 2012.
- ^ "GPS.gov: Selective Availability". gps.gov. Archived from the original on 19 February 2014. Retrieved 3 October 2012.
- ^ "GPS and Golf". leaderboard.com. Archived from the original on 17 October 2012. Retrieved 3 April 2018.
- ^ "GPS Accuracy Levels". nps.edu. Archived from the original on 14 October 2012. Retrieved 3 October 2012.
- ^ "The Journal on Navigation Glossary". The Journal on Navigation. Archived from the original on 22 January 2023. Retrieved 2 May 2022.
- ^ "Body of missing B.C. man Albert Chretien found in Nevada". CBC. 1 October 2012. Archived from the original on 2 October 2012. Retrieved 3 October 2012.
- ^ Knudson, Tom (30 May 2012). "'Death by GPS' in desert". The Sacramento Bee. Archived from the original on 4 December 2014. Retrieved 30 November 2014.
- ^ Goessl, Leigh (17 March 2012). "GPS fail: Japanese tourists follow course into Australian waters". Digital Journal. Archived from the original on 1 October 2012. Retrieved 3 October 2012.
- ^ a b c d HEUSSNER, Ki Mae (5 March 2010). "GPS Mishaps: When Trust in Tech Leads to Trouble". ABC News. Archived from the original on 16 October 2018. Retrieved 23 March 2019.
- ^ Saranow, Jennifer (18 March 2008). "Drivers trust GPS even to a fault". Wall Street Journal. Archived from the original on 22 January 2023. Retrieved 3 October 2012.
Last May [2007], the North Yorkshire County Council in England put up signs at the entrance to a gravel track declaring it "unsuitable for motor vehicles" after navigation systems had sent drivers on it as a shortcut between two valleys. The rough road quickly turns stony with steep drops in some places, and locals have had to help cars turn around.
- ^ Zaremba, Lauren (10 May 2011). "GPS mishap results in wrong turn, crushed car". The Review. Archived from the original on 22 June 2013. Retrieved 3 October 2012.
- ^ Messmer, Ellen. "Want security, privacy? Turn off that smartphone, tablet GPS". Network World. Archived from the original on 24 April 2013. Retrieved 12 February 2013.
- ^ Joyce, Kenneth J. "Global Positioning Systems and Invasion of Privacy". Legal Talk. Archived from the original on 7 April 2013. Retrieved 12 February 2013.
- ^ Yamshon, Leah (10 February 2010). "GPS: A Stalker's Best Friend". PCWorld. Archived from the original on 18 December 2012. Retrieved 12 February 2013.
- ^ KARLIN, RICK (15 September 2011). "GPS used to track fired state worker raises privacy issue". TIMESUNION. Archived from the original on 3 February 2013. Retrieved 12 February 2013.