Radar Doppler Multiplexing with Unequal Intervals for Target Detection
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Solution Overview
Problem
Existing radar systems, particularly MIMO radars, face challenges in accurately detecting target objects due to ambiguity in Doppler frequency caused by time-division multiplex transmission, which limits the detectable Doppler frequency range and introduces uncertainty in relative velocity measurements.
Innovation Solution
A radar apparatus that employs Doppler multiplex transmission with unequal intervals, where transmission signals from multiple antennas are simultaneously transmitted with varying Doppler shift amounts, allowing for improved demultiplexing and accurate detection of Doppler frequencies by utilizing differences in reception power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If time-division multiplex transmission is used in MIMO radar, then multiple transmission signals can be transmitted through multiple antennas, but the detectable Doppler frequency range is limited and ambiguity occurs in Doppler frequency measurement
Solution Approach 1:
The patent segments the transmission signals by assigning different Doppler shift amounts to different transmission signals. This allows the receiver to distinguish between multiple transmission signals through Doppler frequency analysis, resolving the ambiguity that would otherwise occur in time-division multiplex transmission. Each transmission signal is segmented in the Doppler frequency domain, enabling accurate measurement while maintaining multiple signal transmission capability.
2Measurement precision
If multiple transmission signals are transmitted simultaneously with different Doppler shift amounts, then the detectable Doppler frequency range can be extended, but the system complexity increases
Solution Approach 1:
The patent changes the Doppler shift parameter of transmission signals to extend the detectable Doppler frequency range. By systematically varying the Doppler shift amounts according to a predetermined pattern, the system achieves extended measurement range while keeping the signal processing complexity manageable through structured parameter assignment rather than arbitrary changes.
3Measurement precision
If Doppler multiplex transmission with unequal intervals is used, then target object detection accuracy is enhanced, but the transmission signal design becomes more complex
Solution Approach 1:
The patent employs asymmetric Doppler shift interval design in the Doppler multiplex transmission. Instead of using equal intervals, different Doppler shift amounts are assigned to different transmission signals in an asymmetric pattern. This asymmetric design enhances target object detection accuracy by improving the distinguishability of reflected waves while the asymmetry itself provides a structured approach that manages signal design 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 method extends the detectable Doppler frequency range, reduces ambiguity, and enhances the accuracy of target object detection, enabling precise velocity measurements and improved angular resolution.
Implementation Method 1
transmits outputs a first transmission signal with a first central frequency and a second transmission signal with a second central frequency... the second central frequency is higher than a frequency (1+1/Nc) times the first central frequency
Data Source
AI summary
Provided is a radar apparatus that detects a target object with high accuracy. The radar apparatus includes: transmission circuitry, which, in operation, alternately outputs a first transmission signal with a first central frequency and a second transmission signal with a second central frequency higher than the first central frequency for each transmission period; and one or a plurality of transmission antennas, which, in operation, transmit the fast transmission signal and the second transmission signal. The second central frequency is higher than a frequency (1+1/Nc) times the first central frequency, where Nc is an integer indicating a number of times of transmission of each of the first transmission signal and the second transmission signal for the each transmission period within a predetermined duration.