Radar Target Simulation Using Doppler-Aware Resampling
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Solution Overview
Problem
Existing radar target simulation systems fail to accurately simulate radar targets due to deviations caused by carrier frequency and bandwidth, leading to significant errors, particularly in modern automotive radar systems with frequencies around 80 GHz and bandwidths of 4 GHz.
Innovation Solution
A radar target simulation system that accounts for both the constant Doppler frequency shift dependent on the carrier frequency and the varying baseband frequency by using a resampling unit to rescale the input signal in time and frequency domains, combined with a delay unit to adjust the number of samples based on the target velocity, ensuring precise simulation regardless of carrier frequency and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar target simulation systems are used, then the simulation is simple to implement, but the simulation accuracy deteriorates due to deviations caused by carrier frequency and bandwidth
Solution Approach 1:
The simulation system is divided into multiple digital processing channels, with each channel independently simulating a specific radar target. Each channel contains separate delay units, resampling units, and frequency shifting units that work independently to process signals for different targets, enabling parallel simulation of multiple targets with different velocities while maintaining high accuracy
Solution Approach 2:
A resampling unit is introduced as an intermediary component between the delay unit and frequency shifting unit. This resampling unit specifically addresses the bandwidth-induced frequency deviations by rescaling the signal in the frequency domain, acting as a mediator that corrects the simulation errors caused by the interaction between carrier frequency and bandwidth
2Measurement precision
If the bandwidth of the radar system is increased, then the measurement capability is improved, but the simulation error increases due to frequency deviations from the carrier frequency
Solution Approach 1:
The system dynamically adjusts the resampling factor based on the instantaneous frequency deviation caused by bandwidth effects. By changing the resampling parameter in real-time according to the frequency offset, the system compensates for the simulation errors that arise when bandwidth is large relative to the carrier frequency, thereby maintaining simulation reliability
3Adaptability or versatility
If the velocity of the radar target is increased, then the simulation coverage is improved, but the Doppler frequency shift calculation becomes more inaccurate due to bandwidth effects
Solution Approach 1:
The system employs dynamic resampling where the resampling factor is continuously adjusted based on the simulated target velocity and instantaneous frequency. This dynamic adaptation ensures that even at high velocities where bandwidth-induced frequency deviations are significant, the Doppler frequency shift is calculated accurately by continuously compensating for the frequency scaling effects
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
Enables precise simulation of moving radar targets with high accuracy, allowing for the testing of radar systems by correctly incorporating both contributions to the Doppler shift, thereby improving the reliability of radar system testing.
Implementation Method 1
The first contribution depends on the carrier frequency of a radar signal, which is constant over time and which causes a Doppler frequency shift that only depends on the velocity of the radar target that is to be simulated
Implementation Method 2
The second contribution depends on the baseband frequency of the radar signal, which varies over time. The invention is based on the finding that the effect of the second contribution can be described by a rescaling of the input signal in time domain and/or in frequency domain
Data Source
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AI summary
A radar target simulation system for simulating at least one moving radar target is disclosed. The radar target simulation system comprises an analog to digital converter (22) and at least one digital processing channel (24). The digital processing channel (24) comprises a delay unit (30), a resampling unit (32) and a frequency shifting unit (34). The delay unit (30) is configured to receive a digitized input signal from the analog to digital converter (22) and to forward the input signal to the resampling unit (32) and/or to the frequency shifting unit (34) with a predetermined time delay. The frequency shifting unit (34) is configured to adapt a frequency of the input signal based on a carrier frequency of the input signal and based on a velocity of the moving radar target that is to be simulated. The resampling unit (32) is configured to rescale the input signal in time domain and/or in frequency domain based on at least one of a momentary frequency of the input signal, a baseband frequency of the input signal, the carrier frequency of the input signal and the velocity of the moving radar target that is to be simulated. Moreover a method for operating a radar target simulation system (14) is disclosed.