Three-Axis Error Equalization Attitude Determination for Spacecraft Based on Virtual Dual Field-of-View

Attitude determination serves as a critical foundation for spacecraft to accomplish various space missions. The conventional single field-of-view (FOV) operating mode of attitude sensors suffers from inherent observational geometric limitations, resultingin significantly larger errors for the boresight roll angle than for the right ascension and declination attitude axes. This issue severely restricts the application of such sensors in high-precision space missions, including space target positioning and high-resolution remote sensing. Existing multi-FOV joint attitude determination methods address the challenge of three-axis error imbalance through optical system improvements or multi-sensor integration. However, these approaches often involve complex system designs and substantial payload overhead. In this paper, without modifying or adding any optical system, we construct a virtual dual-FOV joint observation scenario by correlating multiple sequentially acquired star images. This strategy effectively mitigates the large deviation of the Z-axis attitude angle and achieves more equalized three-axis error performance. Experimental results demonstrate that under the virtual dual-FOV configuration with a 30° separation angle, the proposed method maintains high measurement accuracy for the right ascension and declination of the camera boresight, while reducing the root-mean-square error of the rotation angle around the boresight direction from 7.0213″ to 1.6398″, corresponding to an improvement of 76.65%. This paper provides a novel technical approach for high-precision, three-axis-equalized attitude determination using single-FOV attitude sensors.