MIMO Radar Random Phase Center Motion Decouples Angle-Doppler Coupling
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Solution Overview
Problem
Existing MIMO radar techniques fail to fully exploit phase center motion as a design parameter, leading to inadequate angular and Doppler resolution and interference mitigation, particularly due to angle-Doppler coupling and neglect of space-time coding for orthogonality.
Innovation Solution
A method and system that utilize random phase center motion (PCM) in MIMO radar to generate transmit signals, allowing the phase center to vary randomly, thereby creating a virtual array that decouples angle and Doppler domains, and employs matched filter processing to enhance target detection and interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear switching of antenna elements across pulses is used, then angular resolution is improved, but angle-Doppler coupling occurs
Solution Approach 1:
The patent applies non-linear phase center motion trajectories instead of linear switching, making the phase center position vary dynamically according to a non-linear function of pulse index. This dynamic approach decouples angle and Doppler domains while maintaining improved angular resolution, resolving the contradiction between resolution enhancement and coupling avoidance.
Solution Approach 2:
The patent changes the parameter of phase center motion from linear to non-linear by applying amplitude modulation with non-linear phase progression. This parameter change transforms the switching pattern to achieve both high angular resolution and angle-Doppler decoupling, simultaneously improving measurement precision while eliminating harmful coupling effects.
2Measurement precision
If phase center motion is used to improve angular resolution, then Doppler shifts cause loss of orthogonality, but without phase center motion angular resolution is limited
Solution Approach 1:
The patent employs dynamic non-linear phase center motion where the phase center position follows a non-linear trajectory determined by amplitude modulation. This dynamic approach maintains signal orthogonality despite target Doppler shifts by designing the phase progression to compensate for Doppler effects, thereby preserving both improved angular resolution and orthogonality reliability.
Solution Approach 2:
The patent applies preliminary anti-action by pre-compensating for Doppler shifts through carefully designed non-linear phase center motion trajectories. The amplitude modulation scheme is configured in advance to counteract the expected Doppler effects, preventing loss of orthogonality before it occurs and maintaining reliable signal discrimination.
3Object-generated harmful factors
If virtual antenna overlapping is used for side-lobe suppression, then angular resolution decreases, but without it side lobes are high
Solution Approach 1:
The patent changes the approach to side-lobe suppression by using non-linear phase center motion trajectories instead of virtual antenna overlapping. This parameter change in the phase modulation scheme achieves side-lobe suppression while maintaining the full virtual array aperture, thereby suppressing harmful side lobes without degrading angular resolution measurement precision.
Data Source
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AI summary
A method for obtaining an adaptive angle-Doppler ambiguity function (AF) for a target using multiple-input-multiple-output (MIMO) radar, the MIMO radar including a transmit antenna array, the transmit antenna array being at least one-dimensional and having a plurality of antenna elements. The method comprises generating transmit signals for transmission by the transmit antenna array, the transmit signals defining at least a first transmit trajectory of a phase center within the transmit antenna array. The method further comprises transmitting the transmit signals using the transmit antenna array and receiving receive signals from the target, the receive signals resulting from the incidence of the transmit signals upon the target. The method further comprises obtaining at least an angle-Doppler ambiguity function (AF) from the receive signals. The method is characterised in that the first transmit trajectory is such that, in operation, the phase center undergoes random phase center motion (PCM), such that a phase center position within the transmit antenna array varies randomly with time. A system for obtaining an AF is also disclosed.