Project Overview:
Hope is an amateur rocketry tracker that doesn't use the GNSS system, instead communicating with three ping stations located on the ground to triangulate its position in space.
Hardware -
Hope inherits the same RP2040 architecture as LEO and Lyra, but replaces the IMU and barometer for a NiceRF SX1280 module. The board is 4 layers, assembled by JLCPCB. The same radio module is used for the ranging exchanges and telemetry downlink.
Schematic and board files can be found here
Software -
The software for Hope was written using the Arduino framework, and interfaces with the radio module over SPI to control the ranging measurements and send data down to the ground station. The flight unit pings the three ground stations then sends those distances along with a timestamp down to the data receiever unit, which calculates the position of the flight unit and displays it.
Integration -
Hope has the unique ability to be integrated into totally RF opaque avionics sections without requiring an external GPS antenna, only needing an external 2.4ghz downlink/ranging antenna to function. It can be integrated anywhere an external antenna can be mounted, with only a 1s lipo to support. Hope has been flight tested to 20kft AGL, with a positive ranging ping at this height.