Hybrid Cooperative Positioning in Harsh Environments

Hybrid cooperative positioning involves the combination of satellite pseudoranges with measurements based on terrestrial radio signals, with the aim to improve both coverage and accuracy. This paper presents a theoretical analysis of hybrid cooperative positioning in low signal-to-noise ratio environments, explicitly accounting for scenarios where receivers can receive signals but cannot decode navigation messages. We propose an extended pseudorange model, suitable for evaluation of measurements made by the receiver in these scenarios, as well as extended cooperation across agents attempting to enable satellite navigation functionality of receivers operating below signal-to-noise ratio threshold required for proper message decoding. The advantages of such extended cooperation are illustrated on a realistic scenario by means of the Cramer-Rao lower bound.