Travel Direction (Heading) as reported by GX400

Can someone direct me to any documentation on how travel direction (heading) are reported by the GX400? When I log into the modem I can see the heading as shown in degrees (0 - 359). But it appears that when the modem sends data to our listening device it is dividing the degrees in half and sending that number instead. For instance, if the modem is heading south, or 180 degrees, we are seeing 180 degrees reported when looking at the modem but the data sent to the listener is 90 degrees instead of 180 degrees. Is there any documentation on how this works or can somebody confirm that this is the intended behavior?

Topic moved to the correct location.