Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesWhen GPS or another GNSS signal is unavailable, jammed or unreliable, a ground robot can estimate its movement with onboard inertial sensors, use cameras or other sensors to locate itself from its surroundings, or combine those inputs. None is a universal fix: inertial estimates drift, environmental cues depend on what the robot can sense, and localization alone does not make a vehicle capable of safe off-road driving.
What “GPS-denied” means
GPS is one satellite-navigation system; GNSS is the broader family of satellite-navigation systems. A robot is often described as operating in a GPS-denied environment when satellite positioning is unavailable, degraded or deliberately disrupted. Jamming is one possible cause, not the only one.
Without a usable satellite position, the robot must estimate where it is and how it is moving from onboard sensors and information about its surroundings. These methods can support one another, but each has limitations.
How robots estimate motion without satellite positioning
Inertial measurement and dead reckoning
An inertial measurement unit (IMU) measures motion and orientation. A navigation system can integrate those measurements to estimate how far and in what direction the robot has moved since its last known position. This self-contained estimate is called dead reckoning, and its errors accumulate over time.
#1 Best Overall
- With a USB interface, you can directly use the phone data cable on the computer point of view positioning effect; With IPEX antenna interface, the default distribution of active antenna, can be quickly positioned;
- GT-U7 main module GPS module using the original UBLOX 7th generation chip, Software is compatible with NEO-6M. GT-U7 module, with high sensitivity, low power consumption, miniaturization, its extremely high tracking sensitivity greatly expanded its positioning of the coverage;
- USB directly connected to the computer, That is, with the host computer-owned serial port function, no need for external serial module, send IPX interface active antenna;
- If you have any issue when using our product,or you need product use documentation, please contact us directly for assistance.we will reply your problem in 24 hours.We try our best to provide the most professional service for each customer.
- How to use the GPS module better, the link is obtained in the Product guides and documents, please download it before use
DARPA says compact, low-cost MEMS IMUs used on tactical platforms can drift rapidly and lose positional accuracy within seconds of GPS loss. That is DARPA’s characterization of this class of device, not a universal time limit for every inertial navigation system. Its PINPOINT program is intended to improve the capability; the program’s aims should not be read as proof that a finished product already meets them. DARPA’s PINPOINT program addresses self-contained navigation, while its Micro-PNT overview describes design pressures such as cost, size, weight, power and operation in harsh environments.
Vision and cues from the surroundings
Cameras can track motion or recognize visible features and markers that help a robot estimate its position. Their usefulness depends on what the sensors can observe in the particular setting; the available demonstrations do not establish performance in every environment.
Rank #2
- GPS module compatible with NEO-6M 51 MCU STM32, working voltage: 3.6V-5V (or use Micro USB to directly supply power)
- GT-U7 module, with high sensitivity, low power consumption, miniaturization, its extremely high tracking sensitivity greatly expanded its positioning of the coverage.
- GPS module with a USB interface, you can directly use the phone data cable on the computer point of view positioning effect; With IPEX antenna interface, the default distribution of active antenna, can be quickly positioned.
- In the ordinary GPS receiver module can not locate the place, such as narrow urban sky, dense jungle environment, GT-U7 can be high-precision positioning.
- GT-U7 module with USB directly connected to the computer, that is, with the host computer serial port function, without the need to connect to other serial modules
In a 2021 Army-reported demonstration, a small UAV landed on a moving Clearpath Warthog unmanned ground vehicle (UGV) without GPS. The UAV used visual-inertial odometry, onboard computing, low-cost sensors and a custom fiducial marker on the UGV. The Army said the UAV and UGV did not communicate with each other. This shows a specific landing task, not general-purpose UGV navigation. The Army’s account of the demonstration quotes researcher Dr. Stephen Nogar: “UAVs will need the ability to operate with no Soldier intervention, and a critical function is landing autonomously on static and moving ground vehicles, recharging, then taking off to perform new missions.” He added that the UAVs would need to rely on other sources, “such as onboard vision,” because GPS is unreliable and easily disrupted in that use case.
A separate UK government case study reported that a full-scale Land Rover Defender completed unassisted laps of the HORIBA MIRA off-road proving ground without GNSS using passive imaging sensors. The case study described the work as a proof of concept and discussed a planned next phase; it did not establish a current commercial system or a validated all-terrain product. Read the UK government case study.
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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Rank #3
- GT-U7 main module GPS module using the original UBLOX 7th generation chip, Software is compatible with NEO-6M. GT-U7 module, with high sensitivity, low power consumption, miniaturization, its extremely high tracking sensitivity greatly expanded its positioning of the coverage
- GPS baud needs to be set to 9600 instead of 4800; PPS pin is not needed unless using the GPS to drive a hardware high precision clock
- With a USB interface, you can directly use the phone data cable on the computer point of view positioning effect
- USB directly connected to the computer, That is, with the host computer-owned serial port function, no need for external serial module, send IPX interface active antenna
- Note: Please use the GT-U7 GPS module in an open place, the LED will flash after the satellite signal is found. Bad weather and indoor use will affect the accuracy of positioning
Combining sensor inputs
A navigation system can combine information from an IMU, cameras, range sensors, wheel odometry or other sources. Fusion can use complementary inputs—for example, inertial measurements of movement alongside observations of the environment—but the right combination depends on the vehicle, task and conditions. The available evidence does not establish a universally best sensor stack or a standard correction interval for accumulated drift.
Why localization is not the whole off-road problem
Knowing where a robot is does not by itself let it avoid obstacles, choose a route, maintain traction or move safely over uneven ground. Autonomy also depends on perception, planning, vehicle dynamics, terrain and safety.
Rank #4
- Small size, compatible with 2-7 inch traversal Drone on the market
- Selected ceramic antenna and externally expanded PCB
- Compatible power supply, support 3.3V-5V DC power input
- Onboard POWER and PPS indicator lights, the working status is clear at a glance
DARPA’s RACER program studies autonomy algorithms for UGVs on unstructured off-road terrain through simulation and field experiments over varied terrain. It targets mobility at speeds comparable to a human driver; that is a program goal, not a guarantee that any GPS-denied robot can safely travel at those speeds. DARPA’s RACER program page describes the effort.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to assess a GPS-denied robot claim
When comparing systems or evaluating a demonstration, check what the robot actually used and what was tested. A result in a controlled task is not automatically evidence of reliable operation across different terrain or missions.
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- Car positioning in navigation
- Mobile phones, tablet PCs, handheld devices
- Embedded positioning device
- Wearable device
- Position source: Was the estimate based on inertial dead reckoning, visible features or markers, another sensor, or a fused estimate?
- Drift management: How does the system correct or bound error as time passes after a trusted position fix? The sources cited here do not establish a universal correction interval.
- Sensing conditions: Did the test depend on visible features, a prepared marker or other environmental structure? Do not assume it will work in conditions the demonstration did not evaluate.
- Vehicle and terrain: Was the system tested indoors or outdoors, on structured or unstructured terrain, and with a vehicle whose movement resembles the intended platform?
- Evidence level: Distinguish a program objective, simulation, proof of concept, outdoor experiment and independent evaluation. They establish different things.
- System constraints: Consider sensor cost, size, weight, power, onboard computing, communications and mission needs together rather than treating accuracy as the sole criterion.
An older procurement example illustrates why evidence level matters. In its 2012 review of the Army’s Autonomous Navigation System, the U.S. Government Accountability Office reported that the system had demonstrated functions including obstacle avoidance and following a lead vehicle over varying terrain, but had not entered independent testing. GAO also reported that an expert Red Team found no unique basic navigation capability compared with the six other military and commercial systems it reviewed, while noting the Army system’s off-road design. The report concerns a cancelled program, so it is a caution about evaluating demonstrations and requirements—not a description of current robots. Read GAO’s report.
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