External modules

A powerful feature of LabSat is the ability to record and replay external data, synchronised to within 63nS of the GPS recorded data.

We have three I/O modules available, an RS232 serial module, a RS422 or RS485 module and a CAN input/output module.

For example, if you are developing an integrated GPS and INS (Inertial Navigation System) solution, you could record the data from the IMU alongside the GPS data during a test drive or flight. Putting the system back on the bench, you could disconnect the IMU, and connect the output from LabSat instead and replay the whole test with the LabSat recreating the exact IMU data in time with the GPS data, saving expensive in-field testing.

We have carried out exactly such a test with a Novatel SPAN system connected to a Honeywell HG1700 IMU. We fitted the system to a vehicle and shared the GPS and IMU data with a LabSat using the serial interface module. The 100Hz data from the SPAN system was recorded during this journey, and then the system was set up on the test bench with the Honeywell IMU replaced with the output from the LabSat.

The live sky output was then compared with the bench test, and the position and velocity were virtually identical, as you can see from the graph where the red and blue velocity and position traces sit on top of each other.