Mobile Body Position Control Under GNSS Multipath Conditions
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Solution Overview
Problem
Existing GNSS systems, such as GPS, face significant challenges in reducing multipath errors, which occur when direct and reflected signals reach the antenna simultaneously, leading to noise in distance measurement and positioning inaccuracies, especially in environments where passive methods are ineffective.
Innovation Solution
A mobile body control device that includes a self-position estimation unit, a movement control unit, and a multipath reduction action signal output unit, which controls the mobile body to take specific movements like turning or spiral movements when in a multipath environment to reduce the influence of multipath errors, thereby stabilizing self-position estimation and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive methods are used to reduce multipath influence (antenna design, satellite selection, correlation processing), then positioning accuracy is improved in some conditions, but the method is ineffective when multipath signals dominate the direct wave
Solution Approach 1:
Instead of trying to block or filter multipath signals passively, the invention inverts the approach by actively generating artificial multipath signals that interfere with the dominant multipath signals from buildings. The mobile body emits signals that create controlled interference patterns, turning the harmful multipath environment into a controllable condition where artificial multipath dominates natural multipath, thereby improving positioning accuracy in urban canyons and other multipath-prone environments.
2Measurement precision
If the mobile body moves to reduce multipath influence, then positioning accuracy is improved, but the movement control complexity increases
Solution Approach 1:
The invention introduces an intermediary component - the multipath reduction action signal output unit - that mediates between the positioning system and the movement control system. This intermediary generates control signals that automatically adjust the mobile body's movement based on detected multipath conditions, eliminating the need for complex manual control algorithms and reducing overall system complexity while maintaining positioning accuracy.
3Measurement precision
If active multipath reduction methods are implemented, then positioning accuracy in multipath environments is improved, but the system complexity increases
Solution Approach 1:
The invention makes the mobile body's signal transmission unit serve multiple functions: its primary function of communicating with satellites is enhanced with a secondary function of generating artificial multipath signals for active multipath reduction. By reusing existing hardware components for dual purposes, the system achieves active multipath reduction capability without proportionally increasing system complexity, as the same transmission equipment performs both navigation communication and multipath interference generation.
Data Source
AI summary
The influence of multipath on the positioning calculation based on positioning signals transmitted from satellites is reduced. A self-position is estimated using a positioning calculation result based on a positioning signal transmitted from a satellite. Movement of a mobile body is controlled on the basis of the estimated self-position. A multipath reduction action signal is output when the mobile body is in a multipath environment. The mobile body is controlled so as to take a multipath reduction action when the mobile body is in a predetermined movement state and the multipath reduction action signal is output.