Phase-Conjugate Radar Target Emulation for DSB FMCW Ghost Suppression
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Solution Overview
Problem
Radar target and scene emulation systems for testing dual sideband frequency modulated continuous wave (DSB FMCW) radars face challenges with undesirable ghost images appearing closer to the radar than the desired target, leading to premature activation of safety features like automatic braking, which is impractical and potentially dangerous for vehicular testing.
Innovation Solution
A phase-conjugate target emulation method using an array of frequency-shifting transponders that swap the roles of normal and ghost sideband components, with a proxy transponder located at a mirror image location to transmit signals, ensuring the desired emulant appears closer to the radar than the ghost image, and applying phase and gain corrections to accurately simulate radar targets for DSB FMCW radars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency-shifting transponders are used to emulate radar targets, then the radar can be tested without real targets, but ghost images appear closer to the radar than desired targets causing premature safety feature activation
Solution Approach 1:
The patent applies phase conjugation to invert the phase of the reflected signal, which swaps the positions of the desired target image and the ghost image. By inverting the phase of the signal reflected from the transponder array, the system makes the ghost image appear at a greater range than the desired target, preventing premature safety feature activation while maintaining accurate target emulation.
Solution Approach 2:
The patent changes the phase parameter of the signal by introducing a phase conjugation operation. This parameter change transforms the signal such that the ghost image position is inverted relative to the desired target position, resolving the measurement precision issue without compromising the reliability of safety feature activation.
2Measurement precision
If real targets are used for testing vehicular radars, then accurate radar performance can be measured, but testing is impractical and potentially dangerous
Solution Approach 1:
The patent uses an array of frequency-shifting transponders to create artificial copies of radar targets. These transponders receive radar signals and retransmit them with modified frequency and phase characteristics, creating virtual images of targets at controlled positions and ranges. This copying approach enables accurate radar testing without the dangers and impracticalities of using real targets.
Solution Approach 2:
The frequency-shifting transponder array acts as an intermediary between the radar system and real targets. The transponders receive signals from the radar, process them through frequency shifting and phase conjugation, and retransmit them back to the radar. This intermediary mechanism enables the radar to test against controlled virtual targets rather than real-world objects, improving both safety and feasibility.
3Object-generated harmful factors
If in phase and quadrature balancing is applied to eliminate ghost images, then some ghost suppression is achieved, but complete elimination is not possible
Solution Approach 1:
Instead of trying to balance and suppress ghost images through complex I/Q balancing, the patent inverts the phase of the reflected signal to swap the positions of desired targets and ghost images. This inversion approach is simpler and more effective, completely eliminating the harmful ghost images while maintaining reliable target detection.
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 effectively shifts the ghost image further than the desired emulant, preventing premature activation of safety features and enhancing the accuracy of radar target detection, thereby improving the reliability of radar testing without the risks associated with real-world testing.
Implementation Method 1
an array of frequency-shifting transponders for emulating physical radar targets
Implementation Method 2
The transponders receive radar signals from the radar DUT and transmit radar signals back to the radar DUT
Implementation Method 3
generating an output signal to be transmitted by the proxy transponder to the radar DUT by swapping roles of a normal sideband component and a ghost sideband component
Implementation Method 4
The receiver of the FMCW radar mixes the received signal with the transmitted signal to produce an intermediate frequency signal
Data Source
AI summary
A method for phase-conjugate target emulation for testing a DSB FMCW radar includes selecting a proxy transponder from an array of frequency-shifting transponders to transmit an emulated target radar signal to a radar DUT. The proxy transponder is located at a mirror image location with respect to a desired DoA of a signal from an emulated radar target. The method further includes receiving a radar signal from the radar DUT and generating an output signal to be transmitted by the proxy transponder to the radar DUT by swapping roles of a normal sideband component and a ghost sideband component of the output signal such that the ghost sideband component appears to the radar DUT as a desired emulant and the normal sideband component appears to the radar DUT an undesired ghost sideband component. The method further includes transmitting the output signal to the radar DUT.