Direction of Arrival Estimation Using Virtual Beam Monopulse Synthesis
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Solution Overview
Problem
Existing DOA estimation methods, such as Capon's beamforming and MUSIC algorithm, require additional antennas to achieve better resolution and are limited in detecting multiple targets, necessitating an improvement in radar detection accuracy.
Innovation Solution
The method employs digital beamforming and monopulse techniques using at least two antennas arranged with a squint angle to produce multiple virtual beams, which are then synthesized into monopulses to determine the direction of arrival (DOA) of an object, enhancing angular resolution without the need for extra antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Capon's beamforming or conventional digital beamforming is used, then angular resolution is improved, but the number of antennas required increases
Solution Approach 1:
The patent introduces a temporal dimension by creating multiple virtual beams at different time delays. Instead of increasing the spatial dimension (number of antennas), the system creates multiple beam directions through time-based signal processing, achieving high angular resolution with a fixed small number of physical antennas.
Solution Approach 2:
The patent creates multiple copies of the same physical antenna system through digital beamforming. By generating multiple virtual beams from the same physical antennas at different time delays, the system effectively replicates the functionality of having multiple antennas without physically adding them.
2Measurement precision
If MUSIC algorithm is used, then angular resolution is improved, but the number of detectable targets is limited
Solution Approach 1:
The patent makes the beamforming system dynamic by continuously creating multiple virtual beams at different time delays. This dynamic approach allows the system to adaptively track multiple targets without the mathematical limitations of MUSIC algorithm, as the system can resolve targets based on temporal beam patterns rather than eigenvalue decomposition.
Solution Approach 2:
The patent segments the detection process into multiple virtual beams created at different time delays. Each virtual beam can independently detect targets, and the system combines results from all segments, enabling simultaneous detection of multiple targets with high angular resolution.
3Productivity
If more antennas are added to detect more targets, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical addition of physical antennas with a digital signal processing approach. Instead of adding more physical antenna elements that would increase circuit complexity, the system uses digital beamforming to create multiple virtual beams from a fixed number of antennas, reducing hardware complexity while maintaining detection capability.
Solution Approach 2:
The patent makes the existing antenna system universal by enabling it to perform multiple detection functions simultaneously through digital beamforming. The same physical antennas create multiple virtual beams that can detect different targets at different angles, making the system multi-functional without adding hardware.
Data Source
AI summary
A method for determining a DOA (Direction of Arrival) comprises the following steps: (a) providing at least two antennas arranged with a squint angle; (b) producing at least two base beams between two adjacent base beams; (c) every two virtual beams of the multiple virtual beams which cross together at a specific angle are define to a virtual beam set; (d) synthesizing the two virtual beams of each one of the virtual beam sets to be a monopulse; and (e) determining the DOA of the object according to comparison between magnitude of demodulated signals corresponding to the monopulses. A device for estimating a DOA is also disclosed.