A software package for evaluating the performance of a star sensor operation

Abstract

We have developed a low-cost off-the-shelf component star sensor (StarSense) for use in minisatellites and CubeSats to determine the attitude of a satellite in orbit. StarSense is an imaging camera with a limiting magnitude of 6.5, which extracts information from star patterns it records in the images. The star sensor implements a centroiding algorithm to find centroids of the stars in the image, a Geometric Voting algorithm for star pattern identification, and a QUEST algorithm for attitude quaternion calculation. Here, we describe the software package to evaluate the performance of these algorithms as a star sensor single operating system. We simulate the ideal case where sky background and instrument errors are omitted, and a more realistic case where noise and camera parameters are added to the simulated images. We evaluate such performance parameters of the algorithms as attitude accuracy, calculation time, required memory, star catalog size, sky coverage, etc., and estimate the errors introduced by each algorithm. This software package is written for use in MATLAB. The testing is parametrized for different hardware parameters, such as the focal length of the imaging setup, the field of view (FOV) of the camera, angle measurement accuracy, distortion effects, etc., and therefore, can be applied to evaluate the performance of such algorithms in any star sensor. For its hardware implementation on our StarSense, we are currently porting the codes in form of functions written in C. This is done keeping in view its easy implementation on any star sensor electronics hardware.

Low-cost Raspberry Pi star sensor for small satellites

“…For our design, the RPi V2 camera module was used as the image sensor and the Schindler Xenoplan 23-mm lens system as the imaging optics. This setup provided the system with a FOV of 9.31 • × 7 • , and the magnitude of the star detection limit was set to 6.5 ensuring a minimum of 3 stars in the FOV [4].…”

“…This technique is more robust and reliable. In our star sensor, we have used the geometric voting algorithm with a binary search algorithm for star identification [4,11]. The geometric voting uses angular distances from a star to all-stars in the FOV for voting to get the identity of the star.…”

“…Also, in some cases, commercial star sensors are bulky and consume a lot of power, making them impractical to be used in CubeSats [3]. To address this problem, our group started the development of a low-cost star sensor [4] using either readily available components or even building some of them in-house. The first prototype, StarSense, was built using a Star 1000 CMOS detector, a MIL-grade FPGA board, and a custom-fabricated lens system at the cost of around 10,000 USD [5].…”

Wide-field ultraviolet imager for astronomical transient studies

“…12. Pointing and stability of the system are carried out as a two-fold (coarse and fine pointing) operation, using inertial measurement sensors and a star sensor (Sarpotdar et al, 2017), respectively. Here, the attitude sensor obtains the pointing information and corrects the position to an accuracy of ±0.24 • using servomotors, while the star sensor works in the in-ner loop, providing much finer accuracy of around 30 .…”

An Edge Computing Algorithm Based on Multi-Level Star Sensor Cloud

“…A star sensor obtains the star image through charge coupled device (CCD) cameras, obtains the orientation of the star point on the star image, and then locates the position of the spacecraft [1,2]. The star image has a wide viewing angle and high dynamics, which can intuitively display the distribution of star points [3].…”