Radar Doppler Multiplexing With Coded Multi-Antenna Transmission
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Solution Overview
Problem
Existing radar systems face challenges in accurately sensing target objects due to ambiguity in Doppler frequency detection, particularly for lower relative velocities, which limits the effective Doppler frequency range and reduces sensing accuracy.
Innovation Solution
A radar apparatus employing Doppler multiplexing transmission, where phase rotations and orthogonal codes are applied to transmission signals from multiple antennas, allowing simultaneous multiplexing and separation of signals in the Doppler frequency domain, thereby extending the range of unambiguous Doppler frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler multiplexing transmission is implemented with phase rotations and code sequences, then the detectable Doppler frequency range is extended and sensing accuracy is improved, but the device complexity increases due to multiple transmission antennas and signal processing requirements
Solution Approach 1:
The radar system segments the transmission signals across multiple transmission antennas, with each antenna assigned a unique combination of phase rotation amount and code sequence. This segmentation allows the received signal to be separated into distinct Doppler frequency components, extending the unambiguous Doppler frequency range while maintaining manageable complexity through structured signal division
Solution Approach 2:
The invention adds dimensions to the signal space by introducing both phase rotation amounts and code sequences as independent multiplexing parameters. This multi-dimensional signal separation enables extension of the Doppler frequency range beyond conventional limits, transforming a one-dimensional frequency problem into a multi-dimensional signal processing solution
2Loss of information
If the number of multiplexing by code sequence varies for different Doppler shift amounts, then the effective Doppler frequency range is extended, but the signal processing complexity increases
Solution Approach 1:
The system dynamically adjusts the number of multiplexing channels based on the Doppler shift amount. By varying the number of code sequences assigned to different Doppler shift amounts, the system optimizes the use of available signal dimensions, extending the effective Doppler frequency range while adapting processing requirements to actual operational conditions
Solution Approach 2:
The invention changes key signal parameters including phase rotation amounts, code sequences, and their combinations to encode different Doppler frequency components. By systematically varying these parameters across multiple transmission antennas, the system extends the unambiguous Doppler frequency range while maintaining structured signal characteristics for processing
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
This approach enhances target-object sensing accuracy by increasing the detectable Doppler frequency range and reducing ambiguity, improving the overall sensing performance of the radar system.
Implementation Method 1
a transmission circuit that applies a phase rotation amount corresponding to a Doppler shift amount and a code sequence to the transmission signal to perform multiplexing transmission of the transmission signal from the plurality of transmission antennas
Data Source
AI summary
The radar apparatus includes: a plurality of transmission antennas that transmit a transmission signal; and a transmission circuit that applies a phase rotation amount corresponding to a Doppler shift amount and a code sequence to the transmission signal to perform multiplexing transmission of the transmission signal from the plurality of transmission antennas. A transmission delay of the transmission signal is set for a transmission period of the transmission signal. Each of the plurality of transmission antennas is associated with a combination of the Doppler shift amount and the code sequence such that at least one of the Doppler shift amount and the code sequence is different between a plurality of the combinations. A number of multiplexing by the code sequence corresponding to a first Doppler shift amount is different from a number of multiplexing by the code sequence corresponding to a second Doppler shift amount.