Radar Frequency Modulation Monitoring for Ghost Object Prevention
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Solution Overview
Problem
Radar systems used in driver assistance systems face issues with incorrect frequency modulation, leading to errors in object detection, such as incorrectly measured object sizes, undetected objects, and 'ghost objects,' which can cause malfunctioning of safety features like emergency braking, especially under poor weather conditions.
Innovation Solution
A radar system that uses an open- or closed-loop-controllable oscillator to generate a sequence of transmission-frequency-modulated signals, analyzes the frequency profile by averaging over multiple signals, and applies corrective measures or disables the driver assistance system if deviations from the nominal profile are detected, while varying the phase angle of the oscillator to prevent error effects during averaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency modulation is used to measure range and relative velocity, then measurement capability is improved, but incorrect frequency modulation can lead to measurement errors and ghost objects
Solution Approach 1:
The patent applies preliminary action by performing frequency modulation analysis before the radar measurement process. The system analyzes the frequency modulation of transmit signals in advance to detect deviations from the nominal profile, and only then proceeds with object detection if the modulation is within acceptable tolerances. This prevents measurement errors and ghost objects from occurring in the first place.
Solution Approach 2:
The patent implements feedback by continuously monitoring the frequency modulation profile of transmit signals and comparing it against the nominal profile. When deviations are detected, the system provides feedback to either correct the modulation or disable the driver assistance system, thereby maintaining measurement precision and reliability through closed-loop control.
2Reliability
If corrective measures are applied upon detecting frequency modulation deviations, then system reliability is improved, but system availability may be reduced due to disabling the driver assistance system
Solution Approach 1:
The patent applies partial action by implementing a tiered response to frequency modulation deviations. Instead of immediately disabling the entire driver assistance system for any deviation, the system first attempts corrective measures for minor deviations. Only when deviations exceed acceptable tolerances does the system disable the driver assistance function, thus maintaining availability for acceptable conditions while ensuring reliability for critical failures.
3Measurement precision
If frequency analysis is performed on each transmit signal individually, then detection precision is improved, but computational complexity and power consumption increase
Solution Approach 1:
The patent applies merging by combining multiple frequency modulation analyses into a single evaluation process. Instead of performing separate frequency analyses for each transmit signal independently, the system accumulates frequency modulation information from multiple signals and performs a unified analysis, thereby reducing computational complexity while maintaining detection precision through aggregated data.
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 allows for precise determination of object profiles and deviations, enabling accurate object detection and preventing malfunctions in driver assistance systems by correcting frequency modulation errors and disabling the system when necessary, thus ensuring safer operations.
Implementation Method 1
Radar sensors have the advantage of operating reliably even under poor weather conditions and of being capable not only of measuring object distance but also directly the radial relative velocity thereof using the Doppler effect.
Data Source
AI summary
A method for detecting the environment of a motor vehicle utilizing a radar sensor includes bringing about frequency modulation with a controllable oscillator and generating a sequence of transmission-frequency-modulated transmit signals, which each have the same nominal frequency profile. Received signals reflected from objects are evaluated such that an actual profile of the transmission frequency within the transmit signals or a deviation of the actual profile from the nominal frequency profile is established. Depending on an actual profile and/or a deviation determined, correction in the driving of the oscillator and/or correction in the evaluation of the received signals and/or adaptation of the driver assistance function and/or the autonomous driving maneuver function up to and including disabling thereof are performed.