Radar Virtual Antenna Phase Synthesis
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Solution Overview
Problem
Radar systems with two closely spaced antenna elements face noise issues when determining the angle to a target, which are compounded when estimating virtual phase differences, leading to inaccuracies in direction determination.
Innovation Solution
Incorporating a third antenna element spaced apart by an even number of half-wavelengths to synthesize virtual phase differences, with a controller that determines a first virtual phase difference by dividing the beta phase difference by two and applying a sign correction based on phasor comparisons to reduce noise and resolve sign ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two closely spaced antenna elements are used to determine angle to target, then the system structure is simple, but noise effects compound when estimating virtual phase differences leading to inaccuracies
Solution Approach 1:
The antenna array is segmented into two functional groups: closely spaced elements (reference and alpha) for high-precision phase difference measurement, and widely spaced elements (beta) for extended angular coverage. This segmentation allows each group to optimize its strength while compensating for the other's weaknesses through virtual element synthesis.
Solution Approach 2:
Virtual antenna elements serve as intermediaries between the closely spaced alpha elements and the widely spaced beta element. The virtual elements synthesize phase difference information from both groups, mediating the trade-off between measurement precision and angular coverage by combining the advantages of both spacing configurations.
2Adaptability or versatility
If widely spaced antenna elements are used to extend angular coverage, then the measurement range increases, but phase difference errors increase due to larger spacing
Solution Approach 1:
Virtual antenna elements act as intermediaries that synthesize phase difference information from both closely spaced and widely spaced physical elements. This allows the system to achieve extended angular coverage through the beta element while maintaining measurement precision through the contribution of the closely spaced alpha element pair.
Solution Approach 2:
The system dynamically changes the effective baseline parameter by synthesizing virtual elements at different positions between the physical antenna elements. This allows the measurement system to adaptively optimize the effective spacing parameter depending on the target direction, thereby extending angular coverage while maintaining precision.
3Ease of operation
If virtual phase differences are estimated using alpha phase progression, then the calculation is straightforward, but noise errors are compounded
Solution Approach 1:
The system uses feedback from both the alpha phase difference and beta phase difference measurements to correct and refine the virtual phase difference estimation. Rather than relying solely on forward propagation of alpha phase, the beta measurement provides feedback that helps correct accumulated noise errors in the virtual element synthesis process.
Solution Approach 2:
The virtual phase difference estimation uses a composite approach combining phase difference information from two different baseline spacings (alpha and beta elements). This composite measurement strategy is analogous to using composite materials, where the strengths of different measurement configurations are combined to create a more accurate overall estimate than either configuration could provide alone.
Data Source
Figure 1
Figure 2~3
AI summary
A radar system (10) includes a radar antenna (14) and a controller (30). The antenna (14) includes a reference element (20), an alpha element (22) spaced apart from the reference element (20) by one half-wavelength of the reflected signal (12), and a beta element (24) spaced apart from the reference element (20) by an even number of half-wavelengths of the reflected signal (12). The controller (30) is configured to determine an alpha phase difference (40) between detected signals (32) from the reference element (20) and the alpha element (22), determine a beta phase difference (42) between detected signals (32) from the reference element (20) and the beta element (24), and determine a first virtual phase difference (44) that corresponds to the reflected signal (12) expected to be detected by a first virtual element (46) located halfway between the reference element (20) and the beta element (24). The first virtual phase difference (44) is based on the beta phase difference (42) divided by two.