High speed telemetry sufficient to stream video from sounding rockets or balloons requires high gain antennas to get sufficient link budget. But high gain antennas have a narrow field of view and require guidance to point the antenna at the remote transmitter. How do we get that guidance at 100+km range?
This project uses two radio systems: a low bandwidth, low power, long range 900 MHz unlicensed spread spectrum radio, with omnidirectional antennas to transmit packetized GPS location information from a moving remote target station (a high power amateur sounding rocket) to a ground station. The ground station has its own GPS and can thus compute the direction vector to the target station.
A second high WiFi radio system is then used for high bandwidth communications using a ground station controlled high gain, highly directional servo pointed WiFi antenna.