GNSS Post-Processing Using Mirrored Data for Accuracy

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Solution Overview

Problem

Existing GNSS navigation engines are limited in performing backward processing of GNSS data, which is necessary for enhancing the accuracy of position data, especially in harsh environments, and require significant modifications to support such functionality.

Innovation Solution

A post-processing system that uses mirrored GNSS data to enable alternative backward processing, combining the results of forward and modified backward processing to enhance the precision of position data, allowing existing real-time PVT engines to process mirrored data and maintain accuracy without modifying the core engine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If backward processing is implemented to enhance position data accuracy, then measurement precision is improved, but device complexity increases due to requiring significant modifications to the PVT engine

Engineering Contradiction:

Improveposition data accuracyVSAvoidPVT engine complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of modifying the PVT engine to process data in backward time direction, the patent inverts the approach by mirroring the input GNSS data in reverse chronological order. This allows the existing forward-only PVT engine to process the mirrored data as if it were forward data, effectively achieving backward processing results without engine modifications.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a mirrored copy of the original GNSS data where the time sequence is reversed. This copied and mirrored data is then fed into the existing PVT engine, allowing the engine to produce backward processing results through its standard forward processing capability, thus avoiding direct modification of the engine while achieving enhanced accuracy.

Inventive Principle:

Principle #26Copying

2Ease of operation

If forward-only PVT engines are used to avoid modifications, then ease of operation is maintained, but measurement precision is reduced due to inability to perform backward processing

Engineering Contradiction:

Improveengine operation simplicityVSAvoidposition data accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a data mirroring intermediary layer between the GNSS data source and the forward-only PVT engine. This intermediary mirrors the data in reverse chronological order, allowing the simple forward-only engine to operate unchanged while the mirrored data enables backward processing capability to be achieved through the intermediary transformation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11156722B2Post-processing global navigation satellite system (GNSS) position data using mirrored GNSS data

Publication Date: 2021.10.26 TRIMBLE INC

AI summary

A post-processing system providing forward processing (FP) of original GNSS raw data and alternative forward-backward processing (BP) of modified GNSS raw data and combining results of the FP and modified BP to enhance accuracy of position data derived from GNSS raw data. The post-processing system includes a GNSS processing engine, such as a real-time PVT engine, that processes GNSS raw data files as real time data streams equally for FP and BP. The backward processing is performed on a set of GNSS raw data that is mirrored from the original GNSS raw data. The modified BP uses the same algorithms of the PVT engine in a forward run but with the mirrored GNSS raw data to provide BP including position estimate with associated accuracy estimates for each data epoch. A forward/backward combiner combines results of the FP and the modified BP to provide final position data with enhanced precision.