GNSS Multipath Detection With Controlled Phase-Center Movement
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Solution Overview
Problem
Existing GNSS receivers, particularly 'black box' receivers in drones, rails, and automobiles, struggle to accurately navigate in environments with multipath signals due to specular reflections, leading to significant positioning errors, and existing multipath detection methods are complex, costly, or require interventions within the receiver, which is not feasible for these systems.
Innovation Solution
A device and method that generate a controlled movement of the apparent phase center of GNSS antennas to detect multipaths by comparing observable values from the receiver with predicted values, using a control law to analyze residue for anomalies, without altering the receiver's internal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external methods such as optimized radiation pattern antennas or antenna arrays are used to detect multipaths, then multipath detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a movable reflective element (intermediary) that reflects GNSS signals toward the antenna. This intermediary device enables multipath detection by creating a controlled reflected signal path without requiring complex antenna arrays or modifying the receiver itself, thus resolving the contradiction between detection capability and device complexity
Solution Approach 2:
The patent creates a simplified copy of the multipath effect using a movable reflector instead of requiring the full complexity of natural multipath environments or sophisticated antenna systems. The reflector copies the essential characteristic of reflected signals, enabling detection through a simpler mechanism
2Measurement precision
If antenna arrays with controlled radiation patterns are used for multipath detection, then multipath detection accuracy is improved, but device complexity and calibration requirements increase
Solution Approach 1:
The movable reflector acts as an intermediary that simplifies the detection mechanism. Instead of using complex antenna arrays requiring precise calibration, the reflector creates controlled reflected signals that can be detected by a single antenna, maintaining measurement precision while reducing device complexity
Solution Approach 2:
The patent replaces the complex electromagnetic field control required by antenna arrays with a simple mechanical reflector system. The movable reflector physically directs signals rather than relying on complex phase and amplitude control of multiple antenna elements, eliminating calibration requirements
3Reliability
If redundant location means are used for multipath detection, then detection reliability is improved, but volume, weight, and cost increase
Solution Approach 1:
The movable reflector serves multiple functions: it creates reflected signals for multipath detection, can be positioned to simulate different multipath scenarios, and works with the existing GNSS receiver without requiring redundant location systems. This multi-functionality improves detection reliability while avoiding additional weight from redundant hardware
4Adaptability or versatility
If GNSS receivers operate in urban environments with multipath signals, then navigation coverage is improved, but positioning accuracy deteriorates
Solution Approach 1:
The patent performs preliminary multipath detection and characterization before final position calculation. By detecting and analyzing reflected signals in advance, the system can identify and compensate for multipath effects, maintaining positioning accuracy while enabling operation in urban environments with limited satellite visibility
Solution Approach 2:
The system uses feedback from multipath detection to adjust position calculations. By continuously monitoring reflected signals and comparing expected versus actual signal characteristics, the receiver can identify multipath contamination and correct positioning errors, maintaining accuracy in challenging urban environments
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Efficiently detects multipaths in GNSS signals, reducing positioning errors without requiring modifications to the GNSS receiver, offering a simple and effective solution for 'black box' systems.
Implementation Method 1
generate a movement of the apparent phase center according to a predetermined control law
Data Source
AI summary
A GNSS signal multipath detection device (16) for a GNSS receiver (12) on-board a carrier further comprising one or a plurality of antennas (14) and comprising:a movement generation module (22) configured for generating a movement of an apparent phase center according to a control law;a control module (23) configured for determining the control law;a prediction module (24) configured for determining a prediction of an observable value provided by the GNSS receiver (12), from the control law and directions of arrival of the GNSS signals;an anomaly detection module (25) configured for detecting multipaths by comparing an observable value coming from the GNSS receiver (12) with the corresponding prediction thereof.