Attitude determination for balloon-borne experiments

TL;DR

This paper presents an attitude determination system for balloon-borne experiments, combining multiple sensors for real-time and post-flight pointing accuracy, demonstrated on BLASTPol flights over Antarctica.

Contribution

The paper introduces a multi-sensor attitude determination system with real-time and post-flight reconstruction capabilities for balloon experiments.

Findings

Achieved <5' rms in-flight pointing accuracy

Achieved <5" rms post-flight attitude reconstruction

Successfully employed in BLASTPol flights over Antarctica

Abstract

An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of SPIDER, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of <5' rms in-flight, and <5" rms post-flight.