Antenna Pair Offsets for 360-Degree Angle-of-Arrival Measurement
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Solution Overview
Problem
Existing methods for determining the angle of arrival (AoA) of a radio signal are limited to a range less than 180 degrees and require mechanical rotation of antenna arrays, which is inefficient and inaccurate.
Innovation Solution
A method using a pair of antenna pairs offset by different angles to generate unique sum and difference signal ratios, allowing for the calculation of AoA over a full 360-degree range without mechanical rotation, by constructing a look-up table based on theoretical signal differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna pair is used for AoA measurement, then the measurement can be performed with simple hardware, but the measurement range is limited to less than 180 degrees
Solution Approach 1:
The antenna array is segmented into multiple antenna pairs, each pair responsible for measuring AoA in a specific angular sector. By dividing the full 360-degree range into multiple overlapping sectors and using multiple pairs, the system achieves complete coverage while keeping each individual pair relatively simple.
Solution Approach 2:
The patent transitions from a single baseline measurement (one dimension) to multiple baselines with different orientations (multiple dimensions). By introducing antenna pairs with different offset angles, the system adds angular dimensionality to the measurement capability, enabling 360-degree coverage.
2Adaptability or versatility
If mechanical rotation of antenna array is used to achieve 360-degree coverage, then the measurement range can be extended, but the system becomes more complex and less accurate
Solution Approach 1:
The patent replaces the mechanical rotation system with a static antenna array configuration. Instead of physically rotating a single antenna pair to scan 360 degrees, the system uses multiple fixed antenna pairs with different orientations to simultaneously cover the entire angular range, eliminating mechanical complexity and improving measurement accuracy.
Solution Approach 2:
The antenna pairs are pre-configured with specific offset angles to cover different angular sectors before measurement begins. This preliminary geometric arrangement eliminates the need for dynamic repositioning or rotation during operation, achieving 360-degree coverage through static configuration.
3Measurement precision
If antenna spacing is increased to improve angular resolution, then the front beam width narrows and accuracy increases, but multiple maxima appear making measurement ambiguous
Solution Approach 1:
The measurement space is segmented into multiple angular sectors, each handled by a dedicated antenna pair optimized for that sector. This segmentation allows each pair to operate with optimal spacing for its specific range without suffering from the multiple maxima problem that would affect a single pair covering the entire range.
Solution Approach 2:
Different antenna pairs have different local characteristics (different offset angles and orientations) optimized for their specific measurement sectors. Each pair is locally optimized for its angular range, providing high precision without the ambiguity issues that would arise from a uniform configuration covering all directions.
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
Enables accurate determination of AoA over a full 360-degree range with improved precision and reduced mechanical complexity, using signal ratio calculations and look-up tables.
Implementation Method 1
AoA determines the direction of the transmitted signal and, in the general sense, may be determined by measuring the difference in received phase between each element in an antenna array
Implementation Method 2
A common method to measure the phase difference φ is to add the signals from both antennas
Data Source
AI summary
A method for determining an angle of arrival (AoA) of a radio frequency (RF) signal received at an antenna array. The method includes determining theoretical signals to be received at an antenna array having first and second antenna pairs. Antennas of the first antenna pair are offset from each other by a first offset angle and antennas of the second antenna pair are offset from each other by a second offset angle. A look-up table is generated based on the theoretical signals. An RF signal is received at each antenna pair and the antenna outputs in each antenna pair are combined to produce first and second difference values. The first and second difference values are compared to theoretical difference values in the look-up table. A measured AoA of the RF signal is determined based on the comparison of the first and second difference values to the theoretical difference values.