Orbital Parameters Pre-launch Calculation Methods for a Piggyback Launched University Small Satellite

Abstract

Two methods for pre-launch calculation orbital parameters of a university small satellite on a piggyback launch are considered. The first method is based on the satellite latitude argument history numerical analysis of a past similar launches to nearly circular orbit and the perturbed circular motion model for the small satellite orbit prediction. This method requires the following additional information from the launch provider: launch time, orbital inclination and period or altitude to predict the small satellite first passes over the university ground station. The second method is based on the satellite latitude and longitude history analysis of a past similar launches to an arbitrary orbit. These methods were used for pre-flight orbital parameters calculation before launching the first Belarusian State University nanosatellite СubeBel-1 from the Jiuquan spaceport in China. Using two methods, the state vector of the university nanosatellite was predicted on the first day of its flight. For successful nanosatellite telemetry reception by a network of amateur radio stations around the world, averaged orbital parameters in TLE format were generated and published on the Internet. This made it possible for dozens radio amateurs to steadily receive radio signals from the university nanosatellite on the first day of the flight. The antenna pointing angles and the Doppler shift of the nanosatellite radio signal were predicted for the Belarusian State University ground station, which allowed it to be the first in the world to decode the CubeBel-1 telemetry. The second method in the comparison in the first method allowed to reduce absolute pass parameter errors for elevation from 2° degrees to 1°, for azimuth from 3° degrees to 2° and Doppler frequency shift from 350 Hz to 250 Hz.