POS Position Estimation Through GNSS Occlusion Using FPGA Buffering
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Solution Overview
Problem
Existing POS systems struggle to provide accurate position and attitude information when satellite signals are occluded by high buildings, leading to position information loss and affecting coordinate measurement tasks.
Innovation Solution
A POS high-accuracy positioning method under occlusion, utilizing a hardware logic device with a central control unit, GNSS positioning control unit, IMU attitude measurement unit, and Internet of Things control unit, employs a filtering occlusion algorithm to estimate positioning data by caching and filtering GNSS data, and calculating unknown parameters using a fitted curve equation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the POS system uses traditional GNSS positioning method, then the positioning accuracy is high under open sky conditions, but the positioning accuracy deteriorates when satellite signals are occluded by high buildings
Solution Approach 1:
The system performs preliminary actions by caching multiple historical positioning data points (at least three points) before occlusion occurs. This preliminary data storage enables the system to estimate position during signal loss without real-time satellite data, resolving the contradiction between maintaining high accuracy and ensuring reliability under occlusion.
Solution Approach 2:
The patent introduces an intermediary mechanism - a positioning estimation module that uses polynomial fitting algorithms to interpolate missing position data during GNSS occlusion. This intermediary process bridges the gap between available and unavailable positioning data, maintaining continuous and reliable position information even when satellite signals are blocked.
2Measurement precision
If the system caches and processes multiple positioning data points using filtering algorithms, then the positioning accuracy under occlusion is improved, but the computational complexity increases
Solution Approach 1:
The system applies partial action by caching only the necessary minimum number of data points (at least three points) required for polynomial fitting, rather than storing excessive historical data. This selective data retention achieves sufficient positioning accuracy under occlusion while minimizing computational complexity and memory requirements.
Solution Approach 2:
The patent changes the parameter of data quantity by storing multiple positioning data points with different weights, where more recent data points receive higher weights in the polynomial fitting process. This parameter adjustment optimizes the balance between achieving accurate position estimation under occlusion and maintaining manageable computational complexity.
Data Source
AI summary
The present invention discloses a POS high-accuracy positioning method under occlusion, comprising: integrating single-point positioning data and differential correction data for solution to acquire high-accuracy position information; implementing a buffer through an RAM of an FPGA to cache the collected position information and a sampling time; when a satellite signal loss is detected by a system, fetching five pieces of position information from the RAM at a time before the signal is lost and five pieces of position information at a time after the signal is reappeared, and filtering the information to obtain filtered data; constructing an equation by using the filtered data, and estimating a signal lost position. By triggering an occlusion algorithm through the FPGA, the present invention improves an ability of a POS system to work in areas with weak satellite signals and meanwhile reduces an operation time, thereby meeting practical needs.