Small Satellite Identification for multi-payload launch using Doppler Measurements

An unknown small satellite from a multi-payload launch on 04/01/2022 was identified using the processing of Doppler measurements of telemetry radio signals on 11 passes received by the Belarusian State University ground station for the period from 04/14/2022 to 04/15/2022. Using a statistical analysis of the small satellite elevation angle and the Doppler frequency shift of its radio signals in the model of perturbed circular motion, the most probable estimate of the four-parameter state vector of the unknown small satellite was obtained. On the basis of the obtained state vector, subsequent radio communication sessions with an unknown small satellite were predicted, radio signals of its telemetry were received and decoded. The decoded telemetry packets made it possible to identify the Chilean university's PlantSat nanosatellite. After the publication by the NORAD system of an updated database of averaged orbital parameters in the TLE format, the antenna pointing parameters and the Doppler frequency shift at the time of receiving telemetry radio signals for each of the satellites from multi-payload launch on 04/01/2022 were numerically simulated. Based on a probabilistic estimate of the elevation angle and Doppler frequency shift, the PlantSat nanosatellite built by students and engineers of the University of Chile was uniquely identified using the NORAD system database.