MIMO Radar Frequency-Shift Modulation for Weak Target Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MIMO radar systems face challenges with increased noise floor and reduced Doppler dynamic range due to higher correlation and cross-channel residue, leading to shadowing of weaker targets by stronger ones, and existing modulation techniques require excessive computational resources and longer processing times.
Innovation Solution
Implement frequency-shifting code-division multiplexing (FS-CDM) to orthogonalize transmit channels, reducing computational complexity and enhancing Doppler dynamic range without requiring residue estimation and subtraction (REST) processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional transmitter and receiver antennas are added to create MIMO radar systems, then detection resolution is improved, but noise floor increases and Doppler dynamic range is reduced
Solution Approach 1:
The patent applies frequency shifting as a parameter change to orthogonalize virtual channels in MIMO radar systems. By introducing distinct frequency shifts to different transmit-receive antenna pairs, the system separates correlated channels in the frequency domain, reducing cross-channel residue and noise floor while maintaining the resolution benefits of multiple antennas
2Object-affected harmful factors
If residue estimation and subtraction (REST) techniques are used to reduce cross-channel residue, then noise floor is reduced, but computational complexity increases
Solution Approach 1:
The patent applies frequency shifting as a preliminary action before signal processing. By pre-orthogonalizing the virtual channels through frequency domain separation, the system eliminates the need for complex REST processing, reducing computational complexity while achieving the same noise floor reduction effect
3Adaptability or versatility
If code-division multiplexing (CDM) is used for MIMO radar systems, then multiple orthogonal transmit channels are achieved, but Doppler domain dynamic range is restricted by decoding residue
Solution Approach 1:
The patent transitions from time-domain CDM processing to frequency-domain processing. By applying frequency shifts to different transmit channels and processing in the frequency domain, the system separates channels orthogonally without the decoding residue problems that limit Doppler dynamic range in traditional CDM approaches
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Radar systems and methods are provided and include transmitting radar signals with multiple transmit channels using a modulation technique and a frequency shift amount such that radar signals are shifted in frequency from adjacent transmit channels. Received radar signals are processed using first and second signal processing modes. In the first signal processing mode, virtual channel demodulation is performed by matching received radar signals within a radar chirp to a first transmit channel and performing Doppler FFT and range shifting. In the second signal processing mode, virtual channel demodulation is performed by matching received radar signals to a corresponding transmit channel and performing Doppler FFT without range shifting. An optimized data cube is generated based on data cubes from the signal processing modes and based on a strength of a target represented in the data cubes.