GNSS-PPP Positioning Using Lidar Constraints
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Solution Overview
Problem
Current positioning technologies for automatic driving, such as GNSS-PPP, require a large number of base stations for accurate centimeter-level precision and have slow convergence speeds due to numerous parameters to estimate and changing satellite geometry.
Innovation Solution
Combining lidar positioning with GNSS-PPP by using point cloud data to construct constraint conditions that accelerate the convergence speed of GNSS-PPP positioning, eliminating the need for GNSS base stations and improving positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS-PPP technology is used for positioning, then positioning accuracy can be improved, but convergence speed deteriorates due to many parameters to be estimated and slow satellite geometry changes
Solution Approach 1:
The patent performs preliminary action by pre-obtaining high-precision satellite orbit and clock difference data before positioning operations. This preprocessing of critical parameters reduces the computational burden during actual positioning, enabling faster convergence while maintaining centimeter-level accuracy without requiring real-time base station support
Solution Approach 2:
The patent changes parameters by selecting and fixing certain satellite orbital parameters and clock difference parameters as known high-precision values rather than estimating them in real-time. This parameter reduction approach transforms the complex PPP problem into a more tractable solution that converges faster while preserving positioning accuracy
2Measurement precision
If RTK technology is used for positioning, then positioning accuracy with centimeter-level precision can be achieved, but device complexity increases due to need for large number of GNSS base stations
Solution Approach 1:
The patent extracts the essential function of base stations (providing differential correction data) and replaces it with pre-obtained high-precision satellite orbit and clock difference products. This extraction eliminates the need for local base station infrastructure while maintaining RTK-level positioning accuracy through standalone PPP operations
Solution Approach 2:
The patent introduces high-precision satellite orbit and clock difference products as intermediaries between the satellite signals and the positioning solution. These pre-processed products serve as a substitute for base station differential corrections, enabling accurate positioning without requiring physical base station deployment in the service area
Data Source
AI summary
The present application discloses a positioning method and an apparatus, which relate to the technical field of intelligent driving. A specific implementation solution is: determining a first positioning result using point cloud data collected by lidar in combination with a laser point cloud reflection value map; constructing a constraint condition using the first positioning result, where the constraint condition is used to accelerate a convergence speed of solving a receiver position using observation data; performing GNSS-PPP positioning using the constraint condition in combination with observation data of a GNSS receiver to obtain a second positioning result. Using this solution, lidar positioning technology is combined with GNSS-PPP positioning technology to realize a purpose of not relying on a GNSS base station.