MIMO Radar Speed Detection Using Asymmetric Chirp Intervals
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Solution Overview
Problem
The existing MIMO radar systems have a limited speed detection range, leading to false speed detection, ghosting, misrecognition, and reduced electric power, especially when detecting targets with speeds beyond the observable range.
Innovation Solution
The proposed speed detection apparatus employs a transmission antenna array and a reception antenna array, with a chirp control unit that adjusts the intervals of chirp signals to ensure equal intervals between chirp signals from the same antenna and unequal intervals between different antennas, allowing for the calculation of multiple speed candidates and true speed determination through phase error correction and arrival angle estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MIMO radar uses multiple transmission antennas with equal intervals Tc between chirp signals from different antennas, then the system achieves simple time division multiplexing and phase coherence, but the observable speed range is limited and decreases as the number of antennas increases
Solution Approach 1:
The patent applies asymmetry by setting unequal intervals Tc between chirp signals from different transmission antennas. Specifically, the first transmission antenna transmits chirp signals at interval Tc1 and the second transmission antenna transmits at interval Tc2, where Tc1 ≠ Tc2. This asymmetric timing configuration breaks the symmetry that causes speed aliasing in conventional equidistant MIMO systems, enabling the system to distinguish between different speed ranges and expand the observable speed range beyond the traditional limit.
2Speed
If the burst interval TB is increased to expand the observable speed range, then higher speeds can be detected, but the frame rate decreases and detection efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the chirp signal intervals adaptive and variable. The system dynamically adjusts the intervals Tc1 and Tc2 between chirp signals from different antennas based on detection requirements. This dynamic configuration allows the system to maintain a reasonable burst interval TB for high frame rate while using the asymmetric intervals to resolve speed ambiguity, thus expanding the observable speed range without sacrificing detection efficiency.
3Ease of operation
If conventional MIMO radar detects targets with speeds exceeding the observable speed, then detection continues, but false speed readings occur instead of accurate measurement
Solution Approach 1:
The patent applies feedback by using the phase difference information from multiple transmission antennas to correct and verify speed measurements. The system calculates phase differences between signals received from different antennas, uses the asymmetric intervals Tc1 and Tc2 to resolve ambiguity, and provides feedback to determine the true speed. This feedback mechanism enables the system to distinguish between aliased speeds and true speeds, maintaining measurement precision even for high-speed targets that would otherwise produce false readings.
Data Source
AI summary
[Object] To achieve a wide speed expansion range.[Solving Means]A speed detection apparatus includes: a chirp control unit that controls a plurality of chirp signals transmitted from a plurality of transmission antennas such that when the plurality of chirp signals multiplexed between the plurality of transmission antennas is separated for each of the plurality of transmission antennas, intervals TB between the plurality of chirp signals from the same transmission antenna are equal and intervals Tc between the plurality of chirp signals from different transmission antennas are unequal; and a speed determination unit that calculates, on the basis of the plurality of reflected chirp signals received by the plurality of reception antennas, M speed candidates faster than a maximum speed Vmax obtained from the intervals TB, acquires M arrival angle spectra by performing phase error correction and arrival angle estimation on the M speed candidates, and determines a true speed by processing the M arrival angle spectra, M representing a natural number of one or greater.