MIMO Radar Signal Multiplexing for Faster Accurate Detection
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Solution Overview
Problem
Existing radar systems face challenges in achieving enhanced target detection accuracy, particularly in combining long-range and short-range modes, which can lead to extended processing times, reduced maximum Doppler frequency detection, and increased hardware costs.
Innovation Solution
A MIMO radar apparatus employs simultaneous code or Doppler multiplexing of transmission signals from multiple antennas, using orthogonal codes to enhance detection accuracy and reduce processing time while maintaining resolution and range requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If long-range and short-range modes are combined in existing radar systems, then detection range and accuracy are improved, but processing time is extended
Solution Approach 1:
The patent segments the transmitted signal into multiple orthogonal code channels (e.g., Walsh-Hadamard codes) that can be simultaneously transmitted through different antennas. Each code channel carries independent radar signals, allowing parallel processing of multiple targets and modes without sequential processing delays, thus reducing overall processing time while maintaining detection accuracy.
Solution Approach 2:
The patent applies pre-coded orthogonal sequences to transmission signals before transmission. This preliminary coding enables the receiver to separate and process multiple signals simultaneously through correlation detection, avoiding the need for sequential processing of different radar modes and reducing processing time.
2Measurement precision
If multiple transmission signals are multiplexed simultaneously, then target detection accuracy is improved, but maximum Doppler frequency detection is reduced
Solution Approach 1:
The patent changes the temporal parameter of signal transmission by using orthogonal codes with different time signatures. Each code channel uses a unique temporal pattern that allows the receiver to distinguish and separately process Doppler information from each channel, preventing Doppler frequency information loss even when multiple signals are multiplexed simultaneously.
3Productivity
If high-speed AD converters are used to improve processing speed, then processing time is reduced, but hardware cost increases
Solution Approach 1:
The patent uses orthogonal code multiplexing to enable partial parallel processing of radar signals, which reduces processing time requirements without needing full high-speed AD conversion capability. The orthogonal codes provide inherent signal separation that allows standard-speed converters to process multiplexed signals effectively, avoiding the need for expensive high-speed hardware.
Data Source
AI summary
A radar apparatus includes signal generation circuitry, which, in operation, generates a plurality of transmission signals transmitted at different transmission start timings, and transmission circuitry, which, in operation, applies different phase rotations to a first transmission signal and a second transmission signal among the plurality of transmission signals and transmits the first transmission signal and the second transmission signal from different transmission antennas. A transmission start timing of the second transmission signal is later than a transmission start timing of the first transmission signal. A part of the first transmission signal and a part of the second transmission signal are transmitted in a first period. A modulation frequency of the first transmission signal at a first timing included in the first period differs from a modulation frequency of the second transmission signal at the first timing.