Quantization-loss Reduction for 1-bit BOC Positioning

Accurate time-delay measurement is essential for positioning with Global Navigation Satellite Systems (GNSS). For mobile receivers small cost, moderate complexity and low energy consumption are desirable. In contrast, Safety-of-Life (SoL) applications require fast processing in order to meet strict time constraints. Concerning these technical considerations, single bit analog-to-digital converters (ADC) are highly attractive as they are simple to build, require low energy and allow to realize high sampling rates and fast digital processing. On the other hand, such systems introduce a loss in the estimation accuracy. In this work we derive a mathematical model for 1-bit GNSS receivers, which takes into account the effects of the analog filters and the non-linear quantizer in the receiver front-end. Based on this refinement we derive analytic formulations for the receiver performance by resorting to the estimation theoretic tools which have become popular for the analysis of ideal receivers with infinite resolution. Finally, we verify the 1-bit quantization-loss for time-delay estimation systems, acting in low SNR scenarios, and investigate possible approaches to reduce this degradation by adjusting the analog front-end.