Ranging Receiver Antenna Diversity for Multipath Error Reduction
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Solution Overview
Problem
Existing RF ranging and locating systems face errors in time of arrival (TOA) measurements due to multipath reflections, which are not effectively averaged out by repetitive measurements in changing propagation environments.
Innovation Solution
The method employs antenna diversity techniques to determine the arrival time of RF ranging signals by receiving signals via multiple antennas, combining signals to enhance signal-to-noise ratio, and selecting the earliest candidate arrival time to minimize errors caused by multipath reflections, utilizing the fact that these errors are always positive, thus identifying the direct-path arrival time with the smallest error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If repetitive measurements are performed to average out errors, then measurement precision may improve, but the method fails to eliminate errors caused by multipath reflections in quasi-static propagation environments
Solution Approach 1:
The patent segments the received signal into multiple components by using multiple antennas to capture different signal paths (direct path and reflected paths). By processing each antenna signal separately and comparing arrival times, the system can identify and exclude multipath components from the final TOA measurement, resolving the contradiction between averaging errors and eliminating systematic multipath errors.
Solution Approach 2:
The patent introduces a spatial dimension by using multiple antennas arranged in specific geometries (e.g., uniform linear arrays). This spatial diversity allows the system to distinguish between direct and reflected paths based on their different arrival directions and times, enabling accurate TOA measurement even in quasi-static environments where repetitive temporal averaging fails.
2Measurement precision
If multiple antennas are used to receive RF ranging signals, then TOA estimation accuracy improves by reducing multipath errors, but device complexity increases
Solution Approach 1:
The patent designs the antenna system to serve multiple functions: the same array of antennas used for receiving ranging signals also provides the spatial information needed for multipath separation. The antenna array serves both as a signal collector and as a geometric reference for determining signal arrival directions, eliminating the need for separate complex processing systems and reducing overall device complexity.
Solution Approach 2:
The patent utilizes changes in signal parameters (arrival time, arrival direction, signal strength) across different antennas to identify and select the direct path. By monitoring how these parameters vary spatially, the system can dynamically distinguish the desired signal from multipath components without requiring complex signal processing algorithms, thus improving accuracy while controlling complexity.
Data Source
AI summary
Method for determining an arrival time of a RF ranging signal at a ranging receiver, comprising receiving at least one RF ranging signal via a plurality of antennas comprised by the ranging receiver, providing a plurality of antenna signals, each comprising at least a section of the ranging signal as received either by a respective one of the antennas or by a linear combination of at least two of the antennas, determining respective candidate arrival times of the at least one ranging signal from at least two of the antenna signals and determining the arrival time of the at least one ranging signal as the earliest candidate arrival time.