Live Speed option
The DL1PRO and DL1WP models are available with optional output of live speed. This option takes the data from the GPS system and the built in accelerometers and combines them using a kalman filter to provide a real time output of speed with is updated at up to 100Hz and which is resistant to brief GPS outages such as bridges or buildings.
To use the option, the DL1 is installed in the standard way (DL1 PRO: card slot pointing to rear of vehicle, GPS connector facing direction of travel. DL1 WP: GPS connector to rear facing direction of travel), paying particular attention to align and level the unit correctly in the car, and with the GPS antenna on the car roof.
The output rate of the live speed output is set in the serial output, the logging rate, and the CAN output rate as needed.
Typical applications are general speed testing, a traction control signal for an ECU or a live speed signal to other instrumentation in the vehicle. If higher accuracy is required, then please refer to the SPEEDBOX product. For SPEEDBOX click here.
To validate the accuracy of the DL1s live speed output it was installed in a road car along side a production SPEEDBOX unit which was used as a reference. The speeds measured by both units were compared for 2 hours of driving in a mixture of rural and urban conditions. The distribution of errors are shown below, for this extended test the standard deviation of the errors was 0.21m/s. Based on this it would be expected that for a test track conditions the error would be significantly lower, and for very built up urban errors, or testing with significant GPS outages (e.g. tunnels) the results would be worse.