Hybrid MIMO Radar Virtual Array Beamforming
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Solution Overview
Problem
Current radar systems face challenges in generating ultra-high-resolution images in real-time for autonomous driving applications, particularly in meeting the requirements of wide field of view, high angular resolution, and high frame rates, while also dealing with limitations such as long scanning times and high quantization errors due to low accuracy phase shifters.
Innovation Solution
A hybrid MIMO radar system that combines analog and digital beamforming techniques, using multiple transmit and receive antennas to create a virtual array, allowing for simultaneous transmission and reception with phase shifting to achieve improved beamforming gain and resistance to Doppler shift, thereby generating ultra-high-resolution images efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If purely analog beamforming is used, then device complexity is reduced, but measurement precision and resistance to Doppler shift deteriorate
Solution Approach 1:
The patent combines analog beamforming (performed by the transmitter with phase shifters) and digital beamforming (performed by the receiver with digital signal processing) to create a hybrid MIMO system. This merging allows the system to achieve high measurement precision through digital processing while maintaining reduced device complexity through analog preprocessing, thereby resolving the contradiction between complexity and precision.
Solution Approach 2:
The patent introduces a virtual array dimension created by the combination of multiple transmit and receive antennas. This virtual array provides additional spatial dimensions for beamforming, enabling high-precision angular measurement without requiring a physically large antenna array, thus resolving the contradiction between precision and system complexity.
2Measurement precision
If purely digital beamforming is used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges analog beamforming in the transmitter with digital beamforming in the receiver. The analog phase shifters perform preliminary beamforming to reduce the dimensionality of signals requiring digital processing, thereby achieving high measurement precision while reducing the number of ADCs and digital processing channels needed, thus lowering device complexity and cost.
Solution Approach 2:
The patent segments the beamforming process into two parts: analog beamforming at the transmitter handling coarse spatial filtering, and digital beamforming at the receiver handling fine angular resolution. This segmentation allows each part to be optimized independently, achieving high precision without requiring fully digital implementation throughout the system.
3Adaptability or versatility
If wide field of view is achieved, then adaptability is improved, but scanning time increases
Solution Approach 1:
The patent enables continuous coverage of the entire field of view by having multiple transmit antennas simultaneously illuminate different spatial sectors. Rather than sequentially scanning through angles, the system continuously monitors all directions at once through the virtual array formed by multiple antennas, thereby achieving wide field of view adaptability without increasing scanning time.
Solution Approach 2:
The patent uses the virtual array dimension created by combining multiple transmit and receive antennas to achieve wide field of view coverage. The virtual array provides enhanced spatial sampling that allows simultaneous observation of multiple directions, resolving the contradiction between wide coverage and fast scanning by adding spatial dimensions rather than temporal sequencing.
4Measurement precision
If high angular resolution is achieved, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent creates a virtual array dimension through the combination of multiple transmit and receive antennas. This virtual array provides the spatial sampling needed for high angular resolution without requiring a physically large or dense antenna array. The virtual elements are formed through signal processing, achieving high resolution while keeping the physical system compact and manageable.
Solution Approach 2:
The patent merges the spatial information from multiple transmit and receive antennas into a virtual array response. By combining the signals and spatial characteristics of all antenna pairs, the system achieves high angular resolution equivalent to a much larger physical array, thereby resolving the contradiction between resolution and physical complexity.
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
The hybrid MIMO system enables the generation of ultra-high-resolution images in real-time, overcoming the limitations of purely analog or digital beamforming, with improved resistance to Doppler shift and reduced phase quantization errors, thus enhancing the performance and cost-effectiveness of automotive radar systems.
Implementation Method 1
a radar system 100 includes a transmitter 110. The transmitter 110 can include a plurality of transmit antennas 112 configured to simultaneously transmit a set of radar signals 102
Implementation Method 2
a set of received radar signals 104 reflected from one or more targets 50 in the field of view
Implementation Method 3
Each phase shifter 114 of the set of phase shifters 114 can be configured to rotate a phase of a respective one of the plurality of analog signals
Implementation Method 4
resistance to loss of coherent combining of receive signals due to Doppler shift
Data Source
AI summary
Methods, systems, computer-readable media, and apparatuses for radar processing based on a combination of analog beamforming, digital beamforming, and virtual arrays are described. In certain embodiments, a radar receiver receives signals simultaneously transmitted, i.e., concurrently, from a radar transmitter. Each transmitted signal corresponds to the same transmit signal, but with a respective phase being applied. The radar receiver generates, based on the received signals, a virtual array response corresponding to an array of virtual antennas. The virtual array response covers a subset of directions within a field of view to be scanned. In some embodiments, the transmissions from the radar transmitter are generated using analog beamforming, and the virtual array response generated using digital beamforming. In other embodiments, the transmissions from the radar transmitter are generated using digital beamforming, and the virtual array response generated using analog beamforming.