The recommendations below can be used to diagnose common GNSS navigation issues.
It is recommended to create a Debug report that includes the following parameters:
- Number of satellites
- Vehicle power supply voltage (V)
- Vehicle speed (km/h)
- Vehicle route displayed on the map for the selected reporting period
For each problematic vehicle, generate a Debug report. It provides a clear overview of the navigation quality.
The number of satellites is the primary indicator of GNSS performance:
0..7- Poor. Reliable position determination is extremely difficult.8..15- Moderate. Position deviations and track distortion are possible.16..21- Good.
The main diagnostic criterion is the relationship between the number of satellites, the vehicle location, and the vehicle power supply voltage (which clearly indicates whether the vehicle was running or not).
¶ Typical Problem Scenarios
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Scenario 1
If the number of satellites decreases when the vehicle power supply voltage increases, and returns to normal when the voltage drops, the most likely cause is interference from factory-installed or aftermarket equipment inside the vehicle cabin. Since this equipment powers on together with the engine, possible sources include:
- Two-way radios
- Radar detectors
- Dash cameras
- Navigation systems
- Tachographs
- Other electronic equipment
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Scenario 2
If the number of satellites decreases while the engine is running, but only at random intervals, and those intervals coincide with possible unauthorized route deviations, intentional GNSS jamming should be considered.
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Scenario 3
If the number of satellites decreases while the vehicle is parked, regardless of whether the engine is running, and the map shows the vehicle near industrial buildings, it may have entered a garage, warehouse, hangar, or another structure where the GNSS antenna does not have a clear view of the sky.
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Scenario 4
If the number of satellites is always within the Poor or Moderate range, verify that the device has been installed correctly. The installation location may not provide sufficient visibility to GNSS satellites. A hardware defect or device malfunction is also possible.
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Scenario 5
If the number of satellites remains stable but the track, speed, or altitude is obviously incorrect, pay attention to how often the issue occurs and where it occurs.
Position accuracy should be evaluated by a specialist based on the realistic speed, altitude, and route that the vehicle could have achieved under actual road conditions and considering the vehicle's technical condition.
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If the issue consistently occurs in the same geographical area, there is likely a local source of interference affecting the GNSS receiver. In this case, neither a firmware update nor device replacement is likely to solve the problem.
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If the issue occurs frequently in different locations, the cause may be external interference or a device malfunction.
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If the issue occurs only once or a few times within a short period (one or two days), it may be related to temporary GNSS system disturbances or other factors that cannot be identified remotely. Continue monitoring both the frequency and location of the issue.
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To determine as accurately as possible whether the issue is caused by the device itself or by installation or operating conditions, use one of the following methods:
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Replace the device with another identical unit that is known to be functioning correctly. If the same issue occurs with the replacement device, the problem is not related to the device.
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Install the suspected device in a vehicle where identical devices have always operated correctly. If the issue does not occur in that vehicle, the problem is not related to the device.
If neither of these tests rules out the device, it should be considered defective and sent to Navtelecom for diagnostics together with a completed warranty claim form.
Warranty claim templates, the repair shipping address, and additional information are available on our website here.