Design of a Compact, Multi-Frequency, Multi-Constellation GNSS Precise Point Positioning Correction Format

High accuracy, high precision Global Navigation Satellite Systems (GNSS) have been utilised by specialised user markets for over two decades. Traditional high accuracy GNSS systems are not scalable as they require local infrastructure. Precise Point Positioning (PPP) is a GNSS position estimation technique that allows positioning and navigation with centimetre-level accuracy without local infrastructure. The caveat of PPP is the timely transmission of corrections to errors in the GNSS signals. Next generation GNSS satellites such as Galileo, BeiDou and QZSS and other local systems have plans to broadcast corrections for PPP services. However since these services are expected to be limited channel capacity, development of efficient formats for PPP corrections are needed. In this paper proposes a messaging strategy for PPP corrections and test its performance, in terms of data rate and obtained positioning accuracy. Message formats in the literature require 522bps or more to transmit corrections for 70 satellites. By contrast the message format proposed in this paper can transmit information corrections for more than 70 satellites using 52% of the standard satellite-based augmentation system (SBAS) channel's 212bps capacity, while incurring in less than 1cm of positioning accuracy degradation.