Small Aperture Daylight Star Tracker

Project Goal: Develop an alternative to GPS that images and identifies star patterns during the day and night in order to determine orientation with respect to the celestial reference frame.

The prevalence of GPS use in the defense and civilian sectors has made it the target of disruption efforts. An alternative to GPS for determining global positioning in celestial navigation via astrophotography must be able to operate day or night.

The team used star imaging and star pattern recognition to create a custom-designed algorithm to locate global position. Daytime imaging can occur by combining the custom-designed optical system with image stacking to improve signal-to-noise ratio. They also developed a radiometric model to optimize design decisions and predict how the optical system would perform. A unique single, dual-axis gyroscope provided data to determine possible random changes in angle between successive images. These changes were used to calculate the necessary pixel adjustments during the image stacking process.

These additions made the system more robust, which allowed it to determine its orientation under shaky or unstable conditions during both day and night.