The Aeronautical Journal December 2022 Vol 126 No 1306

Remote sensing allows mapping of climate, vegetation and terrain features over large regions on the ground while repeating taking images consistently over years. By this way, it provides planetary-scale measurements over the Earth.

Recently, advanced remote sensing satellites with high agility are increasingly needed in the space applications for fast picturing. High spacecraft rate motion posts design challenges for the gyro-stellar inertial attitude estimate (GS IAE) subsystem to maintain the required attitude knowledge, since star trackers will severely degrade their attitude accuracy when spacecraft is subject to high rate motions.

To meet the tight attitude knowledge accuracy requirement (such as <0.011°, 3 sigma, per axis) for remote sensing instrument (RSI) imaging operations, the satellite attitude is usually provided by a GS IAE subsystem for an advanced high-resolution optical remote sensing satellite which is comprised of one or more star trackers, multiple fiber optic gyros, and estimator implemented within the processor. For that kind of satellite mission, full attitude knowledge performance is required, not only during normal nadir pointing for simultaneous panchromatic (PAN) and multispectral (MS) imaging, but during off-nadir pointing for both multi-trip operation and staring imaging operation, which require high spacecraft rate motion. Such high rate motion is also a mission characteristics for satellites operated at a low altitude orbit (such as <400-km), which is commonly seen in many remote-sensing CubeSats.

To effectively eliminate the effects of star motion-induced errors, measurement error and fuse different sensors to obtain a high accuracy of attitude, many attitude determination algorithms were proposed in the literature. Conventional methods used a variety of Kalman filter (KF) schemes to reduce the spacecraft attitude error as well as gyro bias error. These methods can provide excellent estimation but mostly miss the star motion-induced errors.

This paper, “Gyro-stellar inertial attitude estimation for satellite with high motion rate,” proposes a way to examine the AOCS subsystem level performance (IAE accuracy) using the MEMS gyro-arrays IRU in the GS IAE design; address the subsystem level performance due to array misalignments and component temperature-dependent errors; and investigate various data fusion methods to optimize the IAE performance.

The current challenges in the advancement of satellite remote sensing cover innovative technologies and measurement concepts to solve new problems. Especially, to deal with issues that have come to light after the satellite remote sensing experiments conducted. The issues cover increased spatial coverage and extremely high imaging resolution, increased data storage and exploring synergy of observations, development of the state-of-art AI-based processing approaches, and achieving continuity in consistent satellite observations. All of new applications would rely on higher quality sensing devices accompanied with innovative estimation and control design methodologies.

Read the article Gyro-stellar inertial attitude estimation for satellite with high motion rate, in The Aeronautical Journal, Volume 126 Issue 1306,

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