Accurate and High-Frequency Event-Based Star Tracking
For decades, star trackers have been essential for precision attitude estimation in space. By providing arcsecond-level measurements of a spacecraft’s orientation relative to the celestial frame, these systems support mission-critical guidance, navigation, and control (GNC). Yet conventional star trackers face fundamental limitations, especially in dynamic, resource-constrained environments.
The Limits of Conventional Star Trackers
Traditional star trackers use active pixel sensing (APS) cameras and centroiding algorithms to localize stars. While accurate, this approach has several performance constraints:
- Low temporal resolution: Longer exposure times can introduce motion blur at higher slew rates.
- Resource-intensive operation: Synchronous imaging consumes memory and power, challenging low size, weight, and power (SWaP) platforms.
- Limited dynamic range: Bulky hoods are often required to mitigate lens flare and stray light.
These limitations typically cap reliable performance at around 3°/sec slew rates and 2Hz of temporal resolution, a significant obstacle for agile platforms and next-generation missions requiring high responsiveness and robustness in challenging lighting.
Event-Based Sensing: A Paradigm Shift
Event-based (neuromorphic) sensors offer an alternative. Instead of capturing full image frames at fixed intervals, these sensors asynchronously record changes in brightness at each pixel with microsecond latency, yielding:
- High temporal resolution: Up to 50× faster than APS trackers.
- Minimal motion blur: Reliable tracking during rapid slews.
- Exceptional dynamic range: ~140 dB versus 60 dB for APS.
- Low power consumption: Ideal for resource-constrained platforms.
These advantages enable high-frequency, high-accuracy star tracking that was previously out of reach. Watch our recent webinar to see a live demonstration of the benefits of EBS Star Tracking.
The NEST Project: Kitware’s Event-Based Star Tracking Platform
Kitware developed NEST (Neuromorphic Event-based Star Tracker), a software and hardware stack that brings unprecedented precision and speed to star tracking.
Key performance highlights:
- Temporal Sampling: 50× faster than conventional APS systems.
- Slew Rate: Robust tracking up to 7.5°/sec (vs. 3°/sec).
- Accuracy: 20 arcseconds cross-boresight, 70 arcseconds around boresight.
- Optics & Sensor: Computar M25140MP lens with IMX636 HD dynamic vision sensor (1280×720, <100 μs pixel latency). Processing: Real-time attitude quaternion and angular velocity at >100 Hz using asynchronous extended Kalman filtering.
Kitware’s algorithms improve upon other event-based approaches through circuitry-aware centroiding and asynchronous state estimation, yielding superior accuracy and motion tolerance.
Real-World Validation and Public Data
Unlike lab-only research, NEST has been evaluated using real astronomical events with ground truth from conventional trackers and through-the-atmosphere observations. Kitware has publicly released the system’s data, code, and resources, promoting reproducibility and accelerating innovation:
For organizations interested in integrating event-based star tracking or collaborating on future space-domain sensing capabilities, Kitware provides support for technical integration, algorithmic customization, and open solution sustainment.
Connect with our team to explore how NEST can accelerate your mission objectives and bring next-generation star tracking technology to your platforms.