Putting the Synthetic GNSS Meta-signal Paradigm into Practice: Application to Automotive Market Devices

The concept of Global Navigation Satellite System (GNSS) meta-signal, which relies on the coherent processing of two components broadcast on different frequencies, is gaining significant interest in modern receivers. The resulting meta-signal has a wide Gabor bandwidth leading to high-accuracy pseudoranges and consequently high-accuracy code solutions. An example of GNSS meta-signal is the Galileo Alt-BOC, which combines the E5a and E5b side-band components.

Recent research work has shown that accurate Galileo Alt-BOC pseudoranges can be produced through the synthetic meta-signal reconstruction approach, where high-accuracy pseudoranges are obtained as the combination of side-band code measurements smoothed using the side-band wide-lane linear Carrier Phase (CP) combination.

For high-end receivers, the benefits of high accuracy pseudoranges have been demonstrated. However, in mass-market devices outliers can be present in the reconstructed measurements. Moreover, the original reconstruction approach obtained meta-signal CPs as the average of the side-band CPs hence losing the CP integer nature. This paper extends the applicability of the meta-signal synthetic reconstruction approach by introducing a Half-Cycle Ambiguity Resolution (HCAR) rule for the meta-signal CPs and a pseudorange jump detect-and-recover method to improve synthetic pseudoranges continuity.

The proposed approach has been implemented on the STMicroelectronics TeseoV, triple band multi-constellation receiver able to track E1, E5a and E5b, and represents an example of the application of the synthetic measurement reconstruction meta-signal paradigm. This serves as a special feature in automotive devices where the limited front-end bandwidth and hardware correlation constraints do not allow for direct full Alt-BOC tracking.
Analysis has been conducted considering zero baseline experiments where a professional receiver was used as reference and static tests in the position domain. The experimental results show that the extended synthetic meta-signal approach is effective to produce Galileo Alt-BOC observables whose quality is comparable with that of measurements produced by professional devices implementing full-band Alt-BOC processing.