Potential Problems with GPS Tracking


Potential Problems with GPS Tracking: Satellite image


GPS tracking can normally find the position of your vehicle down to within a couple of metres. However, it is not always 100% correct and sometimes the location is not even available.

So why not? Some possible causes are highlighted below:


Potential problems with GPS Tracking: GPS satellites are not visible

The GPS chip in your GPS Tracking device calculates its location by receiving the time and identification signal from 3 or more satellites. The chip uses this information to work out its position on the globe. However, if less than 3 signals are visible because the line of sight between the GPS device and the GPS satellites is being blocked (i.e., by trees, buildings or metal obstructions in the vehicle), then the unit will not be able to calculate its position accurately.

The signal from the satellite may also get bounced around. This is often known as the “Canyon effect” and can happen when your vehicle is surrounded by tall buildings. In this case, an error will be introduced into the location and the GPS device may show in the wrong location or seem to bounce around.


Potential problems with GPS Tracking: Other environmental condition

Solar flares can also cause distortion in the signal although this tends to be more sporadic and well publicised.


Potential problems with GPS Tracking: Human intervention

There are a number of scare stories about cheap GPS jammers being used to disable GPS tracking devices. Technology is certainly becoming more prevalent although it doesn’t seem to be widespread now. However, there are other things that people will do either on purpose or unknowingly such as putting TFT screens such as sat navs near the antenna or covering with a metal backed folder. The antennas can send through plastic but not metal.


You also need to be careful where you put the antenna. Especially in newer vehicles which have metalised glass or heating strips embedded within the windscreen.


Potential problems with GPS Tracking: Poor mobile network coverage

The unit may not be able to send its location because of a weak or nonexistent mobile signal. GPS tracking units typically send their location over the mobile network so if there is no signal, then the location can be sent. Systems such as AutoAlert have intelligence built into the server to try to predict the location but as more time elapses then the guess becomes more and more inaccurate, or at best just shows the last known location.


As the mobile networks typically prioritize voice over data, you might be showing a strong signal on your phone, but if there is a lot of traffic then the signal might not get through from the unit. Vodafone publishes a list of issues with its coverage, so this is a good first port of call if you’re unit hasnt’ sent a location for a while.

Vodafone faults board.

You could also try checking the local mobile network coverage in your area.


Potential problems with GPS Tracking: No power

Obviously if you’re unit hasn’t got power then this will mean it can’t check and send its location. If you have an AutoAlert installed GPS unit, check the LEDs are flashing, the fuses haven’t blown and it is getting power.

If you’re using an AutoAlert portable unit, check out our post on maximising your portable GPS tracking unit’s battery life.







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See also:

Job Management

GPS Tracking

Instant Messaging


AutoAlert Blog




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