System Design for Pose Determination of Spacecraft Using Time-of-Flight Sensors

Abstract

The pose determination between nanosatellites and the cooperative spacecraft is essential for swarm in-orbit services. Time-of–flight (ToF) sensors are one of the most promising sensors to achieve the tasks. This paper presented an end-to-end assessment of how these sensors were used for pose estimation. First, an embedded system was designed based on the ToF camera with lasers as a driven light source. Gray and depth images were collected to detect and match the cooperative spacecraft in real time, obtaining the pose information. A threshold-based segmentation was proposed to find a small set of the pixels belonging to reflector markers. Only operating on the defined active pixel set reduced computational resources. Then, morphological detection combined with an edge following-based ellipse detection extracted the centroid coordinate of the circular marker, while the center-of-heart rate was calculated as the recognition condition. Next, the marker matching was completed using a deterministic annealing algorithm, obtaining two sets of 3D coordinates. A singular value decomposition (SVD) algorithm estimated the relative pose between the nanosatellite and the spacecraft. In the experiments, the pose calculated by the TOF camera reached an accuracy of 0.13 degrees and 2 mm. It accurately identified the markers and determined the pose, verifying the feasibility of the ToF camera for rendezvous and docking.

Adaptive Fuzzy Fixed-Time Control for Nonlinear Systems with Unmodeled Dynamics

“…Hence, the fixed-time control approach has emerged as a progression of the finite-time control algorithm, specifically designed to calculate the settling time of uncertain nonlinear systems, regardless of the initial conditions [33][34][35][36]. So far, considerable research has been dedicated to exploring fixed-time control techniques suitable for intricate engineering systems, such as airplanes, racing vehicles, and multiagent systems [37][38][39][40][41][42]. In [37], two innovative adaptive fault-tolerant fixed-time control schemes were introduced: the distributed fixed-time control (DFTC) method and the priority-based fixed-time control (PFTC) method.…”

Real-Time Telemetry-Based Recognition and Prediction of Satellite State Using TS-GCN Network

“…In addition, in today's era of satellite digitization and intelligence, analyzing historical satellite telemetry data can help create more realistic digital satellite models, driving the intelligent development of satellites and other spacecraft [27]. Additionally, this can also help optimize and improve satellite control algorithms, ultimately leading to high performance control and industrial applications [28][29][30][31][32][33].…”

Relative Pose Estimation of Non-Cooperative Space Targets Using a TOF Camera

“…In order to obtain the pose when approaching a target, various electro-optical sensors, such as visual cameras [12], infrared cameras [13], LiDAR [14,15] and time-of-flight (TOF) cameras [16,17] are options. In space, sunlight changes greatly and target surfaces are always covered with special material without texture; thus, visual cameras cannot work well in these conditions, but active sensors [18] are robust in these conditions.…”