Jitter detection based on parallax observations and attitude data for Chinese Heavenly Palace-1 satellite.

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Parallax observations from staggered charge-coupled devices (CCDs) have been applied to satellite jitter detection. Nevertheless, the jitter during the initial period of an imaging process cannot be detected. This paper presents an approach that combines parallax observations with the attitude data from attitude-measuring sensors in order to detect the global jitter, including the initial jitter. Low-frequency components, which can be reconstructed from attitude data, account for most jitter energy, and determine the jitter curve's overall shape. We introduce attitude data into parallax observations to constrain the initial jitter and find its optimum estimate. Meanwhile, an offset is extracted from parallax observation images by using a comprehensive matching method. A mathematical model is developed to demonstrate how to calculate the global jitter with the initial jitter and offset. Numerical simulation results indicate that, for pixel-level offset error, the root-mean-square error (RMSE) of the proposed method is 1.4 pixels, while the measurement error near integer multiples of characteristic frequency is amplified significantly. Experiments performed on Chinese Heavenly Palace-1 satellite show that the jitter at 0.12Hz with an amplitude about 6 pixels exists in the cross-track direction, while the down-track jitter results fail to show obvious periodicity.