Performance Analysis and Electromagnetic Compatibility of a Novel Wideband Radio Frequency Remote Sensing Payload

The increase in scale, complexity, and sensitivity of small satellite radio frequency payloads presents challenges in spacecraft level environmental performance testing. The Space Flight Laboratory is developing a novel wideband radio frequency payload for use on multiple satellites as part of a distributed remote sensing system. Qualification of this payload at the spacecraft level is complicated by the range of frequencies requiring analysis, the variety of received signal types, and having to qualify the payload on multiple satellites with differing configurations. This paper presents the system level radio frequency performance testing framework developed to efficiently qualify this new payload consistently in different bus configurations. The goals of this framework were to reliably determine payload receiver performance with frequencies ranging from VHF to X-band, evaluate the impacts of electromagnetic interference, and automate the electromagnetic compatibility and performance test processes such that they could be efficiently run on multiple satellites. Ultimately, this framework has yielded the ability to characterize the performance of a complex wideband radio frequency payload, and efficiently scale that characterization to a fleet of spacecraft

Flight Results of the Attitude Determination and Control System for the NEMO-HD Earth Observation Microsatellite

NEMO-HD is an Earth observation microsatellite designed and built at the Space Flight Laboratory at the University of Toronto Institute for Aerospace Studies (SFL) in collaboration with the Slovenian Centre of Excellence for Space Sciences and Technologies (SPACE-SI) who owns and operates the spacecraft. The mission was launched successfully into a circular Sun-synchronous orbit with 10:30 LTDN at an altitude of 535 km, aboard the VEGA VV16 mission from French Guiana on September 2, 2020. The primary payload is an optical imager, providing still imagery on its panchromatic (PAN) channel with 2.8 m ground sample distance (GSD), 5.6 m GSD on its four multi-spectral channels (R,G,B,NIR), and high definition video with 1920x1080 resolution. To achieve the precise pointing and stability requirements required for high quality optical imagery, the spacecraft is three-axis stabilized using reaction wheels for attitude control, and dual star trackers for attitude determination. The spacecraft has three targeting modes for imaging: inertial pointing, nadir-pointing, and ground target tracking; the exact mode selection depends upon the type of imagery desired. In this paper we discuss spacecraft attitude determination and control system design, and present the detailed attitude determination and control system pointing performance results for the mission in each of the primary operational modes, using one of the two star trackers as the “true” reference attitude