Self-Interference Impact Analysis in Low Earth Orbit Navigation Augmentation Systems

Low Earth Orbit satellite navigation augmentation (LEO-NA) systems enhance the positioning performance of global navigation satellite systems. However, the simultaneous transmission of augmentation signals and reception of navigation signals leads to significant self-interference. The co-frequency transmission approach, while improving spectrum efficiency, creates potential self-interference. This paper investigates the mechanism and impact of self-interference to guide LEO-NA system design. A model was developed using carrier-to-noise ratio (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{C} / \mathrm{N}_{0}$</tex>) degradation and signal acquisition probability as dual metrics, quantifying the minimum required frequency separation to maintain receiver performance. Results confirm that higher power levels degrade receiver performance, especially with cofrequency operation. Employing frequency separation effectively mitigates interference, with larger separation needed for wider interference bandwidths. Optimal suppression occurs when the separation is an integer multiple of the interference bandwidth. These findings establish a critical foundation for developing effective self-interference mitigation techniques in future LEO-NA systems.