Expert Opinions: How many GNSS signals for a consumer-grade device?

December 23, 2015  - By

Question: What is the optimum number of GNSS signals to include/process in a consumer-grade PNT device?


Philip Mattos Receiver Designer Consultant

A: A chip should support four signals, being GPS/GLONASS/Galileo/Beidou, but only process two of them — choice depending on region, geopolitical sensitivity, constellation availability — dropping to one to save power when satellite availability is good. Two constellations give enough satellites for accuracy and availability in obstructed environments. Which two depends on needs regarding cost, power and so on, GPS and Galileo being better in the future for less power, but GPS and GLONASS being better today.

Greg Turetzky<br /> Principal Engineer<br /> Intel

Greg Turetzky

Principal Engineer


A: The receiver should be capable of processing sufficient signals to provide optimum performance in all expected use cases. This means it should be able to support all GNSS and augmentation systems to provide maximum robustness to blockages and interference. The management of receiver resources to accomplish that is highly dynamic on individual epochs and should be invisible to the user in consumer-grade devices. Optimizing tradeoff between performance, power and cost is where the secret sauce lies.

Ruslan Budnik CEO SPIRIT Navigation

Ruslan Budnik
SPIRIT Navigation

A: Two constellations give reliable, fast cold start even after long overseas flights. There is room for improvement in challenging conditions, so application of three constellations is the saturation point. Choose the best combination in different parts of the globe. In Russia that should be GLONASS + 2, in China BeiDou + 2, in Europe Galileo plus two, GPS + QZSS + another one in Japan, and so on. Navigation chipmakers should support all operating satnav systems to offer the best combination, taking into account battery drain.

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