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A satellite navigation receiver traditionally searches for positioning signals using an acquisition procedure. In situations, in which the required information is only a binary decision whether at least one positioning signal is present or absent, the procedure represents an unnecessarily complex solution. This paper presents a different approach for the binary detection problem with significantly reduced computational complexity. The approach is based on a novel decision metric which is utilized to design two binary detectors. The first detector operates under the theoretical assumption of additive white Gaussian noise and is evaluated by means of Receiver Operating Characteristics. The second one considers also additional interferences and is suitable to operate in a real environment. Its performance is verified using a signal captured by a receiver front-end.

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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-tonoise ratio threshold required for proper message decoding. The advantages of such extended cooperation are illustrated on a realistic scenario by means of the Cramér-Rao lower bound.