The development of satellite swarm technology offers new possibilities for space studies and comes with new challenges. Among them is the need for knowledge on the swarm topology and attitude, especially in the context of space based radio interferometry. This paper presents an algorithm that recovers the absolute swarm attitude without the need for an external system such as GNSS (Global Navigation Satellite Systems). This algorithm uses the imaging capability of a low frequency radio interferometer in order to function like a star-tracker using the main radio sources in the sky. The recovery of the source directions for the Lost-In-Space (LIS) mode is presented in this paper. This algorithm is studied through numerical simulations. This concept is applied here to the kilometric wavelength spectral range (30kHz – 1MHz).
Images are reconstructed using an iterative Discrete Fourier Transform (DFT) at two frequencies. The sources contributions are subtracted at each iteration. The modeled interferometer corresponds to the NOIRE (Nanosatellites pour un Observatoire Interférométrique Radio dans l’Espace) concept study. The accuracy on the recovered swarm attitude is measured for different levels of noise in the interferometric visibilities.
The simulation shows that the suggested pipeline can achieve an attitude knowledge error lower than 1 arcmin for a swarm scale of 100 k
