Introduction
GPS -Global Positioning Systemstem as the world’s most popular satellite navigation technology, has been deeply integrated into every aspect of modern life. From the real-time navigation of Uber drivers on the streets of New York, to the tracking of Amazon trucks across state lines, to the monitoring of the migration of wildlife conservationists in Kenya in Africa, to the safe location of skiers in the Alps in Europe, the accuracy of the GPS directly determines the efficiency and safety of the scene. According to the US GPS Industry Association’s 2024 Global Satellite Navigation Market Report, the global GPS-related Industry has reached $85 billion, consumer devices (such as mobile phones, car navigation) accounted for 40% , professional devices (such as mapping, aviation navigation) accounted for 35% .
Many users, however, have experienced GPS“Failures”: between buildings in Tokyo’s Shinjuku District, mobile phone navigation veers off course; while hiking on the edge of the Amazon rainforest, hand-held GPS devices miss by tens of meters; in the underground parking lot of Los Angeles International Airport, vehicles can’t get a signal at all. At the heart of these problems lie fluctuations in the quality of GPS signals. In this paper, the key factors affecting the quality of GPS signals are analyzed in detail from six dimensions: environment, atmosphere, multipath effect, satellite system and equipment performance, combined with global real cases and data, and provide landing optimization suggestions to help users in different scenarios to improve the positioning experience.
Environmental factors: the“Physical barrier” of signal transmission
The environment is the most direct factor affecting the GPS signal. Any shield will weaken or even block the signal transmission between the satellite and the receiver. GPS signal frequency is mainly concentrated in the L 1(1575.42 mhz) and L 2(1227.60 mhz-RRB- frequency band, this kind of electromagnetic wave penetration is weak, easy to be blocked by buildings, terrain, vegetation, etc. , resulting in signal attenuation or interruption.
1.1 blocking by buildings: “Signal Canyons” in cities
In an“Urban Canyon” of high-rise buildings, GPS signals are repeatedly blocked and reflected by skyscrapers, making it impossible for receivers to pick up enough direct signals. Take Manhattan, New York, USA as an example. The average height of buildings in this area is more than 150 meters, and the distance between tall buildings on both sides of some streets (such as Fifth Avenue) is less than 50 meters, the blocking rate of GPS signals is as high as 70% in the morning and evening hours (when the satellite elevation angle is less than 30 °) . According to 2023 data from the New York City Department of Transportation, GPS positioning accuracy in downtown Manhattan is typically 20-50 meters, and in extreme cases (such as heavy rain + morning and evening rush hours) even more than 100 meters, which can be used to determine the location of the location, this led to an 18 per cent increase in delivery timeouts on local food delivery platform DoorDash, an average of 15 extra minutes per order and an increase in operating costs of $3.20 per order.
Similar scenes have been seen in high-rise areas such as Shinjuku in Tokyo and Downtown Dubai. In 2024, a test of GPS signals on 100 streets in the Tokyo metropolitan area by Toyota Motor of Japan showed that the probability of GPS positioning deviation exceeding 30 meters reached 45% when the vehicle was driving on a street with a building height of more than 200 meters, while the probability of GPS positioning deviation exceeding 30 meters reached 45% when the vehicle was driving on a street with a building height of more than 200 meters, on open roads, the probability was only 5% . To alleviate the problem, some cities are experimenting with“Urban signal boosters”: Dubai deploys signal relays every kilometer in the city center at a cost of about $8,000 each, gPS within 500 meters of the surrounding area can be improved to 10-15 meters accuracy, the taxi company’s navigation complaints rate decreased by 32% .
1.2 terrain effects: natural ‘signal filtering’
Mountain, canyon, forest and other terrain will affect the GPS signal through the“Shelter + attenuation” dual effect. In mountainous areas, v-shaped canyons can limit the visible satellite range of receivers-take the Colorado Canyon in the Rocky Mountains, for example, the number of visible satellites in the valley floor usually drops from 8-12 in the open to 3-4(meeting only the minimum requirements for 3D positioning) , and positioning accuracy drops from 2-5m to 30-50m. In 2022, the U.S. National Park Service (NPS) reported that 12% of the lost incidents in Yellowstone were related to weak GPS signals caused by the terrain, 80% of these were in the area around the heavily forested bear tooth highway.
Signal attenuation in forested areas is directly related to vegetation density. Data from tests at the edge of the Amazon rain forest showed that dense coniferous forests reduced GPS signal strength by 60-70% : in open grasslands with no vegetation cover, positioning accuracy was up to 3-5 metres; In dense forests with more than 90% tree cover, the accuracy drops to 15-25 metres. To solve this problem, national geographic expeditions are often equipped with high-gain external antennas (which cost about $200) that can boost reception by 40 percent and restore accuracy to 8 to 12 meters.
1.3 indoor environment: “Total shielding” of signals
GPS signals can not penetrate concrete, metal and other materials, so in indoor, basement, underground parking and other enclosed spaces, the signal will be completely shielded. Tests in the underground parking lot of wal-mart in the United States showed that the pure GPS signal received intensity was 0, making the device completely unable to locate. However, by deploying Wi-Fi hotspot-assisted positioning, the accuracy can be improved to 5-8 meters, enough to guide cars to parking spaces.
The demand for localization in indoor scenes is increasing, especially in shopping malls, warehouses, airport terminals and other areas. In 2024, Amazon installed a“GPS + Bluetooth beacon” fusion system in 100 logistics warehouses across the United States: one Bluetooth beacon (which costs $15 per unit) is installed every 50 meters in the warehouse, combined with GPS signal correction, the positioning accuracy of inventory counting equipment is improved from 10 meters to 1-2 meters, the efficiency of inventory counting is increased by 40% , and the labor cost of each warehouse is saved by about $50,000 per year.
Atmospheric factor: invisible“Signal interference layer”
GPS signals travel from satellites (20,200 km above sea level) through the ionosphere and troposphere. Particles and meteorological conditions in these two layers of the atmosphere can alter the speed and path of signals, leading to positioning errors that are critical in scenarios such as professional mapping and air navigation, it can even lead to safety incidents.
2.1 ionospheric effects: ‘Ripple Effects’ of solar activity
The ionosphere is located at an altitude of 80-1000 km and consists of charged particles (electrons, protons) ionized by solar radiation. These particles refract the GPS signal, causing a signal delay-typically 5-50 nanoseconds (1 nanosecond = 10-9 seconds) , with a positioning error of about 1.5-15 meters. When solar activity is intense (e.g. , solar flares, coronal mass ejection) , the ionosphere experiences an“Ionisation storm” with a delay of up to 100-200 nanoseconds with an error of more than 30 metres.
On April 23,2024, a moderate solar flare (magnitude X2.0) hit earth, causing a significant anomaly in the GPS signal over North . According to the Federal Aviation Administration (FAA) , within an hour of the incident, GPS errors in the eastern United States increased from the normal 2-3 meters to 15-20 meters, the FAA temporarily rerouted aircraft from 12 airports to avoid them veering off the runway. To counteract the effects of the ionosphere, professional equipment usually uses“Dual-band correction” technology: receiving both L-1 and L-2 band signals (most consumer-grade equipment only supports L-1) , the correction is calculated from the difference in delay between the two bands. These specialized mappers cost between $5,000 and $15,000, while l1-only consumer phones typically cost between $200 and $1,000, with an accuracy difference of 20 to 30 meters during ion storms.
2.2 tropospheric effects: “Invisible drivers” of meteorological conditions
The troposphere, located between 0 and 18 km above sea level, is the most active region of the atmosphere for weather change. Changes in temperature, humidity and air pressure change the refractive index of the troposphere, which in turn affects the speed of GPS signals. For every 10 °C increase in temperature, the speed increases by about 0.02% ; for every 10% increase in humidity, the speed increases by about 0.02% , about 0.015% . This change in velocity causes positioning errors, usually between 2 and 10 meters, which increase with altitude.
The test data in the European Alps are very representative: the average temperature in this region is -20 °C in winter and 25 °C in summer, and the accuracy of GPS in winter is 5-8 meters lower than that in summer at the same location. In 2023, Swiss Airlines reported that tropospheric GPS biases accounted for 60% of the total error when flying in the Alps, for which the airline installed an“Air data computer” on the aircraft, by correcting GPS signals with real-time temperature and humidity data, the airline can reduce fuel waste by about $2 million per year.
In the tropics, heavy rainfall also exacerbates tropospheric impacts. Florida in the United States often experiences heavy rain in summer (rainfall > 50 mm/h) . Data from a Miami Express Company in 2023 showed that GPS positioning errors were 3-4 meters more in heavy rain than in sunny days, as a result, 1.2% of parcels are delivered to the wrong address. The cost of handling each incorrect parcel (re-distribution, user compensation) is about $5, with an additional cost of $80,000 due to heavy rains throughout the year.
Multipath effect: the false doppelganger of signals
Multipath effect refers to the phenomenon that GPS signal is reflected by buildings, ground, water and other objects before reaching the receiver, forming“Reflected signal” and“Direct signal” at the same time. When the two signals are superimposed, the receiver miscalculates the distance and mistargets the target-an effect that is most pronounced in urban, watery areas, and so on, is one of the central causes of the decline in GPS accuracy in cities.
3.1 multipath interference in cities: “Reflection traps” in glass curtain walls and bridge decks
Glass curtain wall buildings in modern cities are a major source of multipath effects. Chicago’s Willis Tower, for example, is made of 16,000 pieces of glass that Bounce GPS signals within a kilometer of its perimeter. Tests showed that in the street directly below the building, the strength of the reflected signal reached 70% of the direct signal received by the receiver, with a positioning error of 20-30 meters. In 2023, chicago-based food delivery platform Grubhub reported a 35% error rate in food delivery locations around Willis Tower, resulting in an 18% increase in timeouts and an average $1.50 per order.
The metal of the bridge deck can also cause serious multipath interference. Test data from the Golden Gate Bridge in San Francisco, US, shows that vehicles traveling under the bridge will receive both direct signals from satellites and reflected signals from the bridge deck, with positioning errors of up to 15-20 meters, some vehicles veered off the road due to navigation errors. To combat the problem, California’s department of transportation installed“Multipath Jammers” on the Golden Gate Bridge in 2024, at a cost of about $5,000 per kilometer, which cancel out reflected waves by transmitting signals at specific frequencies, gPS-enabled under-bridge accuracy to 5-8 meters, reducing the accident rate by 30 percent.
3.2 multipath interference around the water: mirror signals between the lake and the sea
Calm water reflects GPS signals like a mirror, creating a“Mirror signal”-a signal with a path difference of 10 to 50 meters, or about 5 to 15 meters, from the direct signal. The multipath effect is especially noticeable in scenes around lakes and oceans.
Tests in the Great Lakes region of the United States have shown that within 100 meters of the shore of Lake Michigan, the GPS position is off by 8 to 12 meters more than in open land inland. In 2022, the United States Coast Guard reported 12 incidents of small boats getting lost, all in calm waters of the Great Lakes: ships GPS showed“Off course” due to multipath effects, captains misjudged directions, and ships were diverted, some ships even ran out of fuel. To avoid such problems, the Coast Guard advises ships to combine compass (a traditional navigational tool) and GPS data when navigating near shore, and use the compass when the difference between the two exceeds 10 meters, this has led to a 65% reduction in near-shore disorientations.
Number and distribution of satellites: “Basic support” for GPS positioning
The core principle of GPS positioning is“Triangulation”: the receiver determines three-dimensional coordinates (longitude, latitude, altitude) by calculating the distance to at least four satellites. Therefore, the number and geometric distribution of visible satellites (that is, the position of satellites in the sky) directly determine the positioning accuracy and stability.
4.1 number of visible satellites: the more the more stable
The GPS constellation consists of 24 working satellites and 6 standby satellites, distributed in 6 orbital planes (4 working satellites per orbital plane) , with an orbital altitude of about 20,200 km and a period of 12 hours. In theory, at least 4 satellites can be seen anywhere in the world at any time, but in practice, the number of visible satellites will be greatly reduced by occlusion.
Open areas: such as the plains of Kansas, the number of visible satellites is usually 8-12, positioning accuracy of 2-5 meters, suitable for agricultural precision seeding (US farms commonly use GPS-guided seeder, accuracy requirements < 3 meters, can reduce seed waste by 30% , saving about $50 per hectare) .
Occlusion area: such as Manhattan, Tokyo Shinjuku, visible satellite number often reduced to 4-6, accuracy 15-30 meters, some scenes even due to insufficient satellite number (< 4) can not be located. In 2023,15% of UPS’s Manhattan delivery vehicles experienced GPS disruption due to a shortage of satellites (just three) , with each vehicle delaying delivery by an average of 30 minutes, add operating costs of about $12 per trip.
To cope with the shortage of satellites, “Multi-system integration”-the simultaneous reception of signals from GPS (America) , GLONASS (Russia) , Beidou (China) and Galileo (Europe)-has become a mainstream solution. Mining companies in the Norwegian Svalbard (Arctic region) upgraded their equipment from a single GPS system to a“GPS + GLONASS” dual system in 2023, increasing the cost of each device by about $300,000, however, the number of visible satellites increased from 3-4 to 6-8, and the success rate of positioning increased from 75% to 98% , reducing the cost of downtime due to positioning failures and saving about $1.2 million per year.
4.2 satellite geometry: the more uniform, the more accurate
The advantages and disadvantages of satellite geometric distribution are measured by“GDOP”: the smaller the GDOP value is, the more uniform the satellite distribution is, and the higher the positioning accuracy is. It is generally believed that:
GDOP < 2: excellent (e.g. open plains, 2-3 m accuracy) ;
2 < gdop < 5: Good (e.g. suburban, accuracy 5-8 m) ;
5 < gdop < 10: general (EG, urban fringe, 8-15 m accuracy) ;
GDOP > 10: Poor (e.g. , downtown, accuracy 15-30 m) .
The change of GDOP value is closely related to time and place. For example, in downtown Los Angeles -LRB-7:00-9:00) , the satellites are mostly concentrated in the southeast direction, wGDOPGDOP values of 8-12 and an accuracy of 15-20 meters; at noon (12:00-14:00) , the satellite distribution is more uniform, wGDOPGDOP values falling to 4-6, accuracy 8-12 meters. In 2024, U.S. Lyft ride-hailing platforms optimized driver navigation based on GDOP data: at times of GDOP > 10, it automatically switched to a“Multi-system fusion mode,” which allows the driver to navigate through the entire ride-hailing system, and remind the driver“The current positioning deviation is larger, please drive carefully”, this measure makes the driver navigation error rate decreased by 28% .
In the navigation scene, the influence of GDOP value is more critical. A 2022 United States Coast Guard report showed that 8 of the 12 incidents of small vessel disorientation were due to satellites concentrating on one side (GDOP > 15) , resulting in positioning deviations of more than 50 meters and vessels off course. To this end, the coast guard requires oceangoing vessels to be equipped with GNSS receivers that support multiple systems (at a cost of approximately $2,000-$5,000) , ensuring that GDOP values remain below 10 and accident rates are reduced by 70 per cent.
Receiver performance: “Core Capabilities” for signal processing
GPS receiver is the terminal of signal receiving and processing. Its antenna quality, chip performance and algorithm optimization directly determine the signal acquisition ability and error correction efficiency. Different grades of receiver in the same environment positioning accuracy difference of up to 10-100 meters, the price from tens of dollars to tens of thousands of dollars.
5.1 antenna quality: the“First threshold” for signal capture
The key parameters of a GPS antenna are“Gain”(a measure of signal amplification) and“Beam width”(a measure of signal reception range) . The built-in antenna gain of consumer devices (such as mobile phones and general navigation devices) is usually 2-3 dBi, the beam width is narrow (about 90 °) , and the signal capture ability is weak in occlusion scenarios; Professional devices, such as outdoor hand-held GPS and aviation navigators, have external antenna gains of 5-8 DBI and a wide beam width (about 120 °) to receive weaker signals.
The National Geographic Society expedition to the Amazon compared the two devices:
Ordinary mobile phones (built-in antenna, gain 2dbi) : signal reception rate of only 40% , 15-25 meters accuracy;
Professional handheld GPS (external antenna, 8DBI gain, price around $600) : 80% reception, 8-12m accuracy.
Antenna design is also crucial in car scenarios. The built-in GPS antenna of the Tesla Model 3 uses a“Multi-element array design” to receive signals from different directions simultaneously, achieving a 25% higher reception rate in urban canyons than traditional vehicle antennas. Although the antenna costs $50 more per vehicle than a conventional antenna, the rate of navigation complaints from Tesla users has dropped by 30% , according to Tesla’s 2024 earnings report, the design has saved the brand about $120 million in customer service costs.
5.2 chips and algorithms: the“Brain” of signal processing
GPS chip is the core of satellite signal processing, its performance directly determines the positioning speed and accuracy. High-end chips usually have“Multi-band reception”, “Multi-system compatibility” and“Fast acquisition” three functions:
Multi-band reception: Support L 1 + L 2 + L 5(L 5 is 1176.45 mhz, stronger anti-interference ability) band, can correct ionospheric errors, such as Qualcomm Snapdragon 8gen 3 chip, support 5 bands, positioning accuracy in the open can reach 1-2 meters;
Multi-system compatibility: receive GPS, GLONASS, Beidou, Galileo signals at the same time, such as mediatek MT6895 chip, can handle 20 + satellite data at the same time, in occlusion scenarios can still maintain stable positioning;
Fast capture: 1-3 seconds after boot can lock the satellite, than the traditional chip (5-10 seconds) faster, suitable for mobile scenes.
The difference in chip performance is directly reflected in the price: High-end chips supporting multi-band and multi-system cost about $50-100, while low-end chips supporting only single-band and single-system cost only $5-10. In 2024, a test of Samsung’s Galaxy S24(with a Snapdragon 8gen 3 chip, which costs about $1,200) compared with the Galaxy S21(with a Snapdragon 660 chip, which costs about $400) in central London, the average positioning accuracy of S24 is 3-5 meters and S21 is 8-12 meters, resulting in a 28 percent increase in customer satisfaction (according to Samsung User Survey) .
Algorithmic optimization is the“Soft power” of accuracy. For example, the“Multipath suppression algorithm” can eliminate the reflected signal by analyzing the phase difference of the signal and reduce the positioning deviation; the“Dynamic Kalman filter algorithm” can combine the motion state of the device (speed, acceleration) , to predict position and reduce errors when a signal is interrupted. The Trimble RTX algorithm, developed by Trimble Inc. , can improve positioning accuracy to the centimeter level (< 10 cm) and costs about $15,000-$30,000, widely used in bridge construction, land surveying and other scenarios, each device can save engineering teams about $50,000 in measurement time costs.
5.3 battery power: “Energy Security” for stable performance
Low battery life can cause a GPS receiver to degrade in order to save power:
The signal sampling frequency is decreased from normal 1 Hz (once per second) to 0.5 Hz or 0.2 Hz, the positioning update is slowed down and the deviation is accumulated
Signal amplification circuit frequency reduction: antenna gain reduction, weak signal capture capability decline;
Multi-system/multi-band functional closure: only single-system, single-band reception is retained, and the number of satellites is reduced.
Data from the US ride-hailing platform Lyft in 2023 showed that 8 per cent of navigation errors occur when a driver’s mobile phone battery is less than 10 per cent: the phone sampling frequency drops to 0.2 Hz, location updates are delayed by up to 5 seconds, and the driver’s battery life is reduced to less than 10 per cent, drivers missed roundabouts by an average of 0.5 miles, adding about $0.30 to fuel costs and a 12 percent increase in passenger complaints.
Outdoor equipment is also significantly affected by the amount of electricity. Garmin’s outdoor watches (such as the Garmin Instinct 2, which costs about $400) are less than 20 percent charged, will automatically switch from“High precision mode”(1 meter level, sampling frequency 1 Hz) to“Normal mode”(5 meters level, sampling frequency 0.5 Hz) , extended from 14 hours to 28 hours. According to Garmin’s 2024 financial report, the feature was used 65 per cent of the time, with users reporting“Basic navigation needs when battery life is low”.
Other factors: nonnegligible“Noise variables”
In addition to the above five core factors, weather conditions and human interference will also have an impact on the quality of GPS signals, among which human interference is more harmful and on the rise globally.
6.1 weather conditions: limited but not negligible
GPS signals are more resistant to most weather conditions, but extreme weather still causes a slight attenuation:
Heavy rain (rainfall > 50 mm/h) : Raindrops will absorb part of the signal, resulting in a 5-10% reduction in intensity and a 2-3 m reduction in accuracy;
Heavy snow (snow thickness > 10 cm) : snow will reflect the signal, resulting in a slight multipath effect, accuracy drop 3-4 meters;
Dense fog (visibility < 100 meters) : fog on the signal effect is very small, the accuracy of only 1-2 meters.
Winter tests in Alaska showed skiers’ GPS watches dropped from 2m to 5m when the snow was 20cm thick, but were still able to navigate, the GPS deviation of delivery vehicles was increased from 3 meters to 6 meters, and some parcels had to be redistributed due to address deviations, adding about $2 per order.
In general, the influence of weather on GPS signals is much smaller than that of environmental and atmospheric factors, and no special response is usually required. Only in extreme weather, other navigation tools (such as maps and compasses) need to be combined.
6.2 human interference: a ‘signal threat’ to global growth
Human interference refers to the blocking or tampering of GPS signals by transmitting radio signals of specific frequencies. It is mainly divided into two categories: “Signal shielding”(jammer) and“Signal deception”(pseudo-signal) . According to a 2024 FCC report, about 2,000 GPS interference complaints are received globally each year, with the US accounting for 25 per cent, Europe for 30 per cent and Asia for 35 per cent.
(1) signal shielding: the“Widespread hazard” of cheap jammers
GPS jammers transmit strong signals with frequencies similar to those of GPS signals, which overwrite the normal signals and cause the receiver to fail to locate. These devices are cheap ($20-$500) and can be easily purchased on e-commerce platforms (e.g. Amazon, eBay) , and are used to evade electronic tolls (ETC) and hide vehicle locations (e.g. theft, illegal transportation) .
In 2023, drivers at a Texas logistics company bought a $200 GPS jammer to avoid ETC tolls on Interstates. The Jammer’s signal coverage of 1 km led to the disruption of all 10 trucks of the company’s fleet in the area, three of which were lost and delayed in delivery, resulting in direct losses of approximately $50,000. Eventually, the company fired the driver, who was fined $25,000 by the FCC (under U.S. law, GPS jammers carry a maximum fine of $100,000 and a year in prison) .
The aviation sector has been particularly hard hit. In February 2024, GPS jamming signals were detected near Los Angeles International Airport, causing five flights to temporarily change their landing runways. A FCC investigation found that a nearby garage had used the jammers to test vehicle electronics, the factory was eventually fined $150,000. To combat the problem, the FAA has deployed“GPS interference monitoring systems” at 30 major airports across the , each costing about $100,000 and capable of locating sources of interference in real time with response times of less than 10 minutes, 60% increase in processing time.
(2) signal spoofing: the“Precision threat” of high-end technology
Signal spoofing refers to transmitting a fake GPS signal so that the receiver mistakenly thinks the fake signal is the real signal and outputs the wrong location. This kind of technology is difficult, high cost (equipment price > $10,000) , mainly used for military, espionage, civilian scenarios occasionally.
In 2022, a signal spoofing incident occurred on the outskirts of Moscow, Russia, when a hacker faked a GPS signal to make the navigation displays of 100 nearby cars“Veer off the road” and drive them into farmland, no casualties. Investigations later revealed that the spoofing devices used by the hackers cost about $50,000 and had a range of 5km. Although such incidents are rare, they are extremely harmful. At present, only a few countries in the world (such as the United States and Germany) have“GPS anti-spoofing” technology, which can identify forged signals by analyzing the encryption characteristics of signals, the equipment costs more than $1m and is used mainly in government and military vehicles.
Practical suggestions for improving GPS signal quality
Combined with the above factors, we provide the following landing optimization suggestions for users in different scenarios, taking into account the cost and effect, to help global readers improve the GPS positioning experience.
7.1 choosing the right environment: avoid signal dead ends
City scene: try to use GPS in open streets, parks and other unobstructed areas. Avoid long stays in narrow streets and underground parking lots between tall buildings. Such as Manhattan in New York, can choose at noon (high satellite altitude angle) navigation, higher than the morning and evening accuracy of 10-15 meters;
Outdoor scenes: when hiking or camping, choose areas with high elevation and no trees (such as mountain tops and open grasslands) . Update your positioning in the open area every 10 minutes to avoid deviation accumulation. The U. S. National Park Service recommends using a“Waypoint” function (such as marking a starting point or water source) on Yellowstone’s forest trails to facilitate backtracking;
Indoor scenarios: for indoor location, turn on the Wi-Fi and Bluetooth assisted location features on your phone, or choose a device that supports UWB (ultra-wideband) technology (e.g. , iPhone 15, Samsung Galaxy S24) , positioning accuracy of 0.3-0.5 m in stores, warehouses, etc. .
7.2 selection of multi-system, multi-band equipment: Increase Signal Redundancy
Consumer users: when purchasing mobile phones and navigation devices, give priority to devices that support the“GPS + GLONASS + Beidou + Galileo” multi-system, apple’s iPhone 15(5 systems) and TomTom GO SUPREME (4 systems, about $300) . The number of visible satellites of this kind of equipment is 50% more than that of single system equipment, and the accuracy is 5-10 meters higher
Professional users: mapping, agriculture, aviation and other scenarios, select support for multi-band (L1 + L2 + L5) equipment, trimble R12i (about $25,000,3-band, 5-system) , Garmin GPSMAP 67(about $600,2-band, 4-system) , it can offset ionosphere and multipath effects with centimeter or meter accuracy.
7.3 optimize equipment configuration: improve signal capture capability
Antenna upgrades: outdoor users can get external high-gain antennas ($20 to $200) , such as Anker’s GPS external antenna (5-dBi, $30) , which improves reception by 30 percent In-car users can install a roof antenna ($50 to $100) to protect themselves from the metal
Power management: when using GPS, make sure the power of the device is more than 20% , to avoid the performance degradation caused by low power. Outdoor users can carry portable chargers (such as the Anker 737, a 26 KMAH, $50,3-4 chargeable phone) ; Car-hailing drivers can install an in-car quick-charge (Belkin, $30,50% in 30 minutes) ;
Algorithm updates: regularly update the device’s GPS firmware and map data, manufacturers will update the location optimization algorithm (such as multipath suppression, dynamic filtering) . In 2024, Google Maps improved location accuracy in urban canyons by 15% with an algorithmic update that users can update in settings-about-version updates.
7.4 responding to human interference: legal compliance and monitoring
Ordinary users: if GPS suddenly interrupted or deviation increased, can try to move to an open area, turn off the device after re-opening; for example, in the airport, near the highway, may be caused by jammers, you can contact your local transportation department or the FCC (US) , Ofcom (UK) etc.
Enterprise users: logistics, bus companies can deploy“GPS interference monitoring equipment”(such as Trimble interference monitor, cost about $5000) , real-time monitoring of interference signals around the fleet, locate the source of interference and alarm;
Legal compliance: GPS Jammers are banned in most countries around the world (e.g. the US, EU member states, China) , and you need to confirm local laws before buying or using them to avoid penalties.
Summary and Future outlook
The quality of GPS signal is affected by six factors: environment, atmosphere, multipath effect, satellite system, equipment performance and human interference. These factors interact with each other and jointly determine the positioning accuracy and stability. From the“Urban canyons” of Manhattan, New York, to the dense forests of the Amazon rainforest, from the tropospheric disturbances of the Alps to the artificial shielding of the Los Angeles airport, the core influencing factors are different for different scenarios, and they are different for different scenarios, users need to optimize the use of targeted.
At present, the technology trends to improve the quality of GPS signal are mainly focused on three directions:
Multi-system deep integration: the cooperative work of GPS, GLONASS, Beidou and Galileo will become the mainstream. In the future, equipment can receive signals from 30 + satellites at the same time, and the value of GDOP will continue to decrease, in urban canyons, the accuracy can reach 3-5 meters
5G + GPS fusion positioning: Verizon in the United States, China’s Huawei and other enterprises are testing 5G base station and GPS fusion technology, using 5G high bandwidth, low delay characteristics, correction of GPS signal error, positioning accuracy in indoor scenes can reach 1-2 meters, plans to promote the global in 2025, the initial investment of about $100 million;
Leo satellite assistance: Leo satellite constellations such as SpaceX’s Starlink and Amazon’s Project Kuiper (orbiting at altitudes of 500-1200 km) will assist in GPS positioning, the number of visible satellites in remote areas, such as the Sahara Desert in Africa and the Arctic, will increase by three to five, with an accuracy of 5 to 8 metres, and the feature is expected to go live by 2026, users pay $10 a month for a subscription.
In the future, with the progress of technology, the quality of GPS signals will continue to improve, and positioning accuracy will move from meter level to centimeter level and millimeter level, the application scenarios will also expand from navigation and logistics to autonomous driving, precision agriculture, UAV distribution and other fields. For global users, understanding the influencing factors of GPS signals and selecting appropriate equipment and use methods will enable them to better enjoy the convenience brought by satellite navigation technology, to avoid the risk and cost loss caused by positioning deviation.
