Automotive Radar Self-Testing via Transition Band Signal Injection
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Solution Overview
Problem
Radar sensors in automotive applications face challenges in ensuring reliable distance and speed measurements, necessitating improved self-test capabilities to maintain functional safety standards like ISO 26262.
Innovation Solution
A radar system with a signal generator, modulator, transmitting and receiving channels, analog-to-digital converter, and computing unit that generates and processes RF test signals within specific frequency bands to enable simultaneous radar target detection and self-testing, utilizing a digital filter with a pass band, transition band, and stop band for effective monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radar system performs self-testing using test signals, then the reliability of the radar system is improved, but the risk of interference with radar target detection increases
Solution Approach 1:
The frequency spectrum is segmented into distinct bands: a pass band for radar target detection and a transition band for test signals. This segmentation allows simultaneous operation of target detection and self-testing without mutual interference, as the test signal frequency is specifically chosen to lie in the transition band where it does not overlap with the pass band used for radar measurements.
Solution Approach 2:
Different frequency regions are assigned different qualities/functions: the pass band is optimized for target detection with appropriate filter characteristics, while the transition band is utilized for test signal injection. This local differentiation of frequency spectrum quality enables both functions to coexist without interference.
2Measurement precision
If the radar system uses a digital filter with pass band and stop band for signal processing, then the measurement precision is improved, but the available frequency range for test signals is reduced
Solution Approach 1:
The filter characteristics (pass band, transition band, stop band) are specifically designed and parameterized to create a transition band that can accommodate test signal frequencies. By carefully selecting the filter parameters, the system maintains high measurement precision in the pass band while simultaneously providing adequate frequency range in the transition band for versatile test signal injection.
3Productivity
If the radar system simultaneously performs target detection and self-testing, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The radar system is designed with multi-functionality to simultaneously perform target detection and self-testing using a single signal processing chain. The digital filter and frequency management system are configured to handle both radar signals in the pass band and test signals in the transition band, eliminating the need for separate testing hardware and enabling productive simultaneous operation.
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 reliable self-testing and simultaneous radar measurement, ensuring the radar system operates within safety standards by using a test signal frequency in the transition band that does not interfere with radar target detection, thus enhancing the reliability of distance and speed measurements.
Implementation Method 1
a modulator configured to generate an RF test signal by modulating the RF signal with a test signal
Implementation Method 2
a receiving channel configured to receive an antenna signal and the RF test signal and to down-convert a superposition of the two to baseband by means of a mixer
Data Source
AI summary
A radar system includes a signal generator configured to generate an RF signal; a modulator configured to generate an RF test signal by modulating the RF signal with a test signal; a transmitting channel configured to generate an RF output signal based on the RF signal; and a receiving channel configured to receive an antenna signal and the RF test signal and down-convert a superposition of the two signals to baseband by means of a mixer in order to obtain a baseband signal. The radar system further includes an analog-to-digital converter configured to generate a digital radar signal based on the baseband signal, and a computing unit configured to filter the digital radar signal by means of a digital filter, wherein the filter characteristic of the digital filter has a pass band, a transition band, and a stop band. The test signal has a frequency in the transition band.