In the system tab, the function print_data reports the telemetry for the ArduPilot; IIRC, it sends about once per second. GPS time isn't included in the telemetry data, but it should be relatively easy to add. For the Ublox GPS, you need to look at…
There is a time field in the GPS data, but I think it varies depending on which GPS you are using. For the Ublox, I think it's milliseconds from the beginning of the week.
This is very similar to the optical triangulation used by the Sharp IR ranging modules. The sharp modules don't have as much range, but are inexpensive and can be spun up to about 10Hz as well. At ERAU, we use them for lateral and vertical ranging o…