Asteroid Doppler Modeling and Frequency-Shift/Light Curves Hybrid Inversion Approach of Physical Parameters for Celestial Velocimetry Navigation

The rotation of asteroids can cause Doppler velocity bias, which reduces the accuracy of celestial velocimetry navigation. Modeling and compensation scheme is an efficacious solution. The physical parameters of asteroids are particularly important for the precise modeling of celestial velocimetry navigation. To provide accurate predictions of Doppler velocity bias for celestial velocimetry navigation, we propose a light/frequency-shift curves hybrid inversion approach (HIA). First, according to the photometric model of asteroids, a Doppler model of asteroids is established. Then, a HIA of asteroids is constructed by combining the light and frequency-shift curves. Finally, the error of the HIA of asteroids is used as the objective function, and then the physical parameters of asteroids are inverted through the Levenberg-Marquardt (LM) search algorithm. In addition, theoretical analysis of observability reveals that the HIA of asteroids is superior to the photometric and Doppler inversion approaches. Simulation results demonstrate that, compared to the photometric and Doppler inversion approaches, the HIA of asteroids provides more accurate physical parameters of asteroids and predictions of Doppler velocity bias. The HIA improves the position and velocimetry accuracy in the line-of-sight (LOS) of the pulsar/velocimetry integrated navigation (PVIN) for spacecraft by 50.89% and 50.03%, respectively.