Event-based Star Tracking under Spacecraft Jitter: the e-STURT Dataset

TL;DR

The paper tackles the problem of spacecraft jitter degrading high-precision pointing by introducing the e-STURT dataset, the first event-camera–based dataset of stars observed under controlled jitter. It combines a Prophesee Gen4 HD event camera mounted on a piezoelectric stage with ground-truth jitter captured by the actuator, collecting 200 sequences across three frequency bands (0-30 Hz, 30-100 Hz, 100-200 Hz). A baseline jitter estimation algorithm operating directly on the event stream is proposed, including event batching, DBSCAN clustering, star centroid tracking, and a displacement hypothesis mechanism to recover jitter. The dataset and baseline method enable development of jitter-aware, high-temporal-resolution space sensing algorithms, with public release and detailed documentation of hardware, methodology, and limitations.

Abstract

Jitter degrades a spacecraft's fine-pointing ability required for optical communication, earth observation, and space domain awareness. Development of jitter estimation and compensation algorithms requires high-fidelity sensor observations representative of on-board jitter. In this work, we present the Event-based Star Tracking Under Jitter (e-STURT) dataset -- the first event camera based dataset of star observations under controlled jitter conditions. Specialized hardware employed for the dataset emulates an event-camera undergoing on-board jitter. While the event camera provides asynchronous, high temporal resolution star observations, systematic and repeatable jitter is introduced using a micrometer accurate piezoelectric actuator. Various jitter sources are simulated using distinct frequency bands and utilizing both axes of motion. Ground-truth jitter is captured in hardware from the piezoelectric actuator. The resulting dataset consists of 200 sequences and is made publicly available. This work highlights the dataset generation process, technical challenges and the resulting limitations. To serve as a baseline, we propose a high-frequency jitter estimation algorithm that operates directly on the event stream. The e-STURT dataset will enable the development of jitter aware algorithms for mission critical event-based space sensing applications.

Figures (13)

• Figure 1: Flow of information between the host (computer), controller and the piezoelectric stage. The host communicates with the controller to provide motion commands and macro parameters. Macros reside on and are executed on the piezoelectric stage, allowing it to experience controlled jitter. This leads to an event stream that is recorded by the host machine.
• Figure 2: The velocity profile of the piezoelectric stage. From rest, the stage first accelerates to reach a predefined $v_{max}$, moves then with constant velocity, and decelerates to reach the target position.
• Figure 3: Sample executions of Algorithm. \ref{['alg:circular_queue']}. Valid values are marked in green and are determined by ensuring that the values of StepCount are in increasing order from top to bottom.
• Figure 4: Sidereal motion in the static sequence. Left: The event stream visualized for the 3-minute long exposure Middle): Median filtering to isolate tracks from stars, Right): Combined visualization for noise and star events.
• Figure 5: Visualization of the first second of data at the start of sequence 17. Columns represent motion along the first axis, second axis and both axes of the piezoelectric actuator respectively. Events belonging to a star are marked in green and noise is represented in red. (Better seen digitally)