Falcom AVL firmware includes the state GPS.Nav.sDeltaSpeed that allows to configure the devices to detect and report any harsh breakings or accelerations produced by the vehicle being tracked. This state uses GPS data in order to detect how fast the speed of the device increases/decreases. It can check speed differences up to an accuracy of 1cm/s. The state compares the current speed with the speed calculated by the GPS receiver just 1 second before. Then, the difference between the current speed and the previous one, will give us as a result the current acceleration value.
- GPS.Nav.sDeltaSpeed>100 //increase of more than 100cm/s ==> acceleration is at least 1m/s²
- GPS.Nav.sDeltaSpeed<-100 //decrease of more than 100cm/s ==> deceleration is at least 1m/s²
According to this, specific DeltaSpeed values can be sent to the server using dynamic entry &(DeltaSpeed.cmps).
Why use GPS instead of internal accelerometer
We think GPS data offers a much more “universal” solution for this kind of functionality. There are two main issues when using the internal accelerometer:
- Since the accelerometer can calculate accelerations in the 3-axis, it is needed to install all the devices in the same way (orientation) inside the vehicle and make sure they are firmly fixed so that they cannot move because of the vibrations.
- It also needs to take into considerations the mass of the vehicle to distinguish between passenger cars and heavy vehicles, for instance.
How to configure this functionality
//Detect harsh accelerations greater than 2m/s²
PFAL,CNF.Set,AL0=GPS.Nav.sDeltaSpeed>200:TCP.Client.Send,0,”Harsh acceleration detected: &(DeltaSpeed.cmps);&(Speed)”
//Detect harsh brakings, deceleration is greater than 1.8m/s²
PFAL,CNF.Set,AL1=GPS.Nav.sDeltaSpeed<-180:TCP.Client.Send,0,”Harsh breaking detected: &(DeltaSpeed.cmps);&(Speed)”
//Besides that, the DeltaSpeed value could be sent to the server periodically together with the GPS positioning data
This feature is available for all Falcom AVL devices running on firmware version 2.9.0 (or superior).