GNSS Timescale Dissemination via Server-Side PPP Processing
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Solution Overview
Problem
The existing method for precise point positioning (PPP) in GNSS systems relies on accurate remote clock signals, which can be unstable and require high-capacity data transmission, leading to potential inaccuracies and long initialization times in case of data interruptions.
Innovation Solution
Implementing a PPP process at the remote server site to generate and transmit an improved timescale signal, which can incorporate high-precision clock data from multiple GNSS receivers, reducing data load and enhancing stability, and allowing for precise time signal calculation without high-precision clocks at client sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If remote clock signals are used for time dissemination in PPP, then time signal can be transmitted to client sites, but the clock signals are unstable and require high-capacity data transmission
Solution Approach 1:
The patent extracts only the essential timing information (timescale T2) from the remote clock signal and transmits it separately from the full GNSS raw data. This allows the client to reconstruct the time signal without receiving the complete high-capacity data stream, reducing data transmission requirements while maintaining stability.
Solution Approach 2:
The system segments the time dissemination process into two parts: (1) transmission of reduced data load containing timing information, and (2) client-side reconstruction of the full time signal using local processing. This segmentation allows efficient data transmission while preserving signal stability.
2Loss of information
If high-capacity data transmission is used to transmit remote clock signals, then more complete time information can be transmitted, but data interruptions have longer initialization times
Solution Approach 1:
The server pre-processes the remote clock signal to extract and prepare timing information in advance. This preliminary action ensures that the essential time data is ready for transmission in a condensed format, reducing the impact of data interruptions and minimizing initialization time when interruptions occur.
3Measurement precision
If PPP process is implemented at remote server site to generate improved timescale signal, then accuracy and stability are improved, but data processing complexity increases
Solution Approach 1:
The patent combines multiple remote clock signals from different GNSS receivers at the server site to generate an improved timescale T2. By merging multiple sources and processing them through PPP, the system achieves higher accuracy and stability while centralizing the complex processing at the server rather than requiring it at each client site.
Data Source
AI summary
A method and apparatus for dissemination of a timescale signal (T2) from at least one server site to at least one client site is provided. The method comprises running, at each server site, a server Global Navigation Satellite System, GNSS, process (202(i)) configured to generate a server GNSS output raw data signal (R7(T2); R7(T2(i))) based at least on one or more first satellite signals; generating a precise orbits and clocks signal (C8(T2); C10(T2); T4(Tppp-T2); T9(Tppp-T2)) embedding said timescale signal (T2) based on all server GNSS output signals (T2(i); T7(T2(i))) and broadcasting said precise orbits and clocks signal (C8(T2); C10(T2); T4(Tppp-T2); T9(Tppp-T2)) via a telecom network (206); running, at each client site, a client Global Navigation Satellite System, GNSS, process (201(c)) configured to generate a client GNSS output raw data signal (R5(T1(c))) based on a client clock signal (T1(c)) and based on one or more second satellite signals, running a client Precise Point Positioning, PPP, process (203(c)) configured to receive said client GNSS output raw data signal (R5(T1(c))) and said precise orbits and clocks signal (C8(T2); C10(T2); T4(Tppp-T2); T9(Tppp-T2)) and to generate a difference signal (T1(c)-T2) between said client clock signal (T1(c)) and timescale signal (T2).