No abstract

Among its payloads, the Canadian Advanced Nanospace eXperiment 2 (CanX-2) nanosatellite is carrying a commercial off-the-shelf GPS receiver, which offers advantages in terms of cost, size and power, and overall continues to perform well more than four years after launch. However, at orbital velocity and with low signal power the receiver is unable to acquire a position fix quickly using its standard acquisition algorithm. In order to effectively collect GPS data over short time intervals, the receiver is manually warm started by pre-assigning channels with PRN and Doppler information. Uploading warm start scripts to the satellite allows for reliable acquisition in an average of 3.5 min compared to a cold start of approximately 20 min, and avoids the need for complex onboard warm start capability. The data collection capability has in turn enabled a variety of scientific results to be obtained.

No abstract

Any future space debris removal or on-orbit servicing mission faces the problem of the initial relative orbit determination of the servicing satellite to the non-cooperative target. In this work, we analyse the relative navigation accuracy that can be achieved in low Earth orbit, by using ground-based orbit determination from radar tracking measurements for the target, and classical GPS-based orbit determination for the servicing satellite. The analysis is based on the radar tracking measurements obtained from a 10 × 10 × 34 cm small object at an altitude of 635 km. The results show that the relative orbit can be determined with accuracy down to 2 m (RMS) in the semi-major axis, and down to 20 m (RMS) in both the radial and normal separations. From the results, we derive requirements on radar-tracking campaigns.

No abstract