Flight results of GPS-based attitude determination for the microsatellite Flying Laptop

Abstract

The paper presents attitude determination results obtained with the “GPS‐Enhanced Navigation system for the University of Stuttgart microsatellite” (GENIUS) onboard “Flying Laptop.” Real flight data have been collected in different measurement campaigns. The performance of the algorithm is evaluated in the presence of typical satellite attitude maneuvers. It is shown that the major sources of errors are offsets and variations of the differential antenna phase patterns. The variations depend on azimuth and elevation angle of the line‐of‐sight vector to the tracked satellite. They lead to systematic errors in the carrier‐phase single differences on the order of a few tens of millimeters. These errors translate into attitude errors up to 1°. It will be demonstrated how much these errors can be mitigated by in‐flight calibration based on carrier‐phase measurement residuals. The flight results will be compared with the prelaunch ground tests and simulations performed, which will provide valuable insight into how realistically the flight performance can be predicted before launch.