The time it takes the Trip Stick to get a satellite lock (also known as time to first fix TFF) can vary, especially where the trip stick is in a moving vehicle or in dense urban areas. The time needed for a GPS lock is usually dependent on how the GPS receiver starts. There are three types of start – hot, warm and cold.
- The Hot Start (average one second) is when the GPS device remembers its last calculated position and the satellites are in view. This happens if the device has been in the last few hours.
- The Warm Start (average 11 – 20 seconds) is when the GPS device remembers its last calculated position. This is normally if the device has not been used for a day or two.
- The Cold Start (average 21 – 50 seconds) is when the GPS device dumps all the information, attempts to locate satellites and then calculates a GPS lock. This takes the longest because there is no known information. A moving vehicle can make this process take longer. This normally happens if the device has not been used for a week.
To help with the process and improve the speed of TFF the PEAK Trip Stick has been equipped with something called AGPS. This means that a small file can be loaded onto the device which essentially tells the device where the satellites can be found. By using AGPS properly you will see the TFF improve significantly. AGPS is added to the device each time you upload your data.
The file that is uploaded has a shelf life however and will decrease its effectiveness over time.
It is therefore highly recommended that you upload regularly (at least once a week) to gain the maximum benefit from AGPS.
Tips to improve GPS accuracy
- Upload at least once a week to get the latest AGPS file and improve accuracy
- Leave the device plugged in all the time
- If you have just returned from holiday start the engine while you load your car to gve the device time to gain a fix
- Place the trip stick in an area where it is most likely to gain a signal for example on your dashboard
- Check the green light is flashing before you set off