Adaptive Antenna Assembly for GNSS Multipath Error Reduction
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Solution Overview
Problem
Standard GNSS receivers face challenges in mitigating multipath errors, particularly in urban environments where objects reflect navigation RF signals, leading to poor precision in Position, Velocity, and Time (PVT) calculations due to the inability to distinguish between Line Of Sight (LOS) and non-LOS signals, which existing complex and costly solutions cannot efficiently address in consumer-grade devices.
Innovation Solution
An antenna assembly with reconfigurable radiation patterns, driven by sensors such as cameras or lidar, classifies the field of view into LOS and non-LOS areas, applying maximum gain to LOS signals and minimizing interference from non-LOS signals, allowing for improved PVT accuracy without requiring significant processing power or external data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard GNSS receivers are used in urban environments, then the device complexity remains low, but the positioning precision deteriorates due to multipath errors from reflected signals
Solution Approach 1:
The antenna's radiation pattern is segmented into multiple independent beams, each covering a specific sector of the sky. This allows selective reception from different directions, enabling the system to focus on LOS signals while rejecting multipath signals from specific directions without requiring complex processing at the receiver level.
Solution Approach 2:
An intermediate processing stage is introduced between the antenna and the GNSS receiver, consisting of signal processing circuits that perform beamforming and multipath rejection. This intermediary layer handles the complexity of signal separation, allowing the use of standard consumer-grade GNSS receivers while still achieving improved positioning precision.
2Measurement precision
If complex processing techniques are applied to mitigate multipath errors, then the positioning precision improves, but the processing power and computational resources increase significantly
Solution Approach 1:
Multipath mitigation is performed in advance through antenna beamforming before the signals reach the GNSS receiver. By pre-separating LOS and non-LOS signals at the antenna level, the subsequent processing in the receiver is simplified, reducing the computational burden and power consumption compared to performing complex mitigation algorithms after signal acquisition.
3Adaptability or versatility
If the antenna radiation pattern is made fixed, then the device complexity is reduced, but the adaptability to different environments deteriorates
Solution Approach 1:
The antenna radiation pattern is made dynamically reconfigurable through electronic beamforming control. The system can adaptively adjust the beam directions and shapes based on the operational environment, transitioning between different radiation patterns to optimize performance in urban canyons, open areas, or mixed environments without requiring physical reconfiguration mechanisms.
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
This solution enhances positioning accuracy in various environments, including urban canyons, by selectively amplifying LOS signals and reducing multipath errors, while being cost-effective and easily implementable in standard GNSS receivers without the need for hardware modifications or external data sources.
Implementation Method 1
a plurality of RF antenna elements adapted to receive the GNSS signals
Implementation Method 2
driving circuits adapted to drive the antenna elements to generate a defined radiation pattern
Data Source
AI summary
The invention discloses an antenna assembly comprising one or more sensors, possibly a fish-eye camera which produces images of the sky above the antenna, said images being processed to identify open sky and occulted sky areas, said identification being used to generate an antenna gain pattern shape wherein null zones are placed on the occulted sky areas, so as to eliminate the GNSS signals which are affected by multipath reflection. The antenna assembly of the invention may be used with any GNSS receiver of the prior art. No specific data on the location of the receiver or its orientation is needed to perform the method of the invention, while in some embodiments, it may be useful to send some information on the number of satellites in view in the open sky.