Redundant Radar Clock Supply for Fail-Operational Sensing
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Solution Overview
Problem
High-performance radar sensors used in autonomous driving systems face increased failure probabilities due to high-frequency components, leading to potential deactivation and safety issues, particularly with quartz oscillators contributing significantly to Failure In Time (FIT) rates.
Innovation Solution
A redundant radar sensor system design featuring multiple sub-sensors with dual clock pulse generators connected via multiplexers for coherent and redundant clock pulse supply, allowing for emergency operation even if components fail, ensuring continued functionality and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-performance radar sensors with many antennas, HF channels and memories are used to improve measurement precision and autonomous driving functionality, then the accuracy and capability of the sensor system is improved, but the probability of failure increases considerably due to more components
Solution Approach 1:
The radar sensor system is divided into multiple independent sub-sensors (first sub-sensor, second sub-sensor), each capable of autonomous operation. This segmentation allows the system to maintain partial functionality even when some components fail, thereby improving reliability while preserving measurement precision through the combined operation of multiple sub-sensors.
Solution Approach 2:
The patent implements beforehand cushioning by providing redundant clock pulse generators (first and second clock pulse generators) and multiplexers that can switch between them. This redundancy ensures that if one clock pulse generator fails, the system can seamlessly switch to another, preventing total system failure and maintaining operational reliability.
2Stability of the object's composition
If a quartz oscillator is used to generate frequencies for the radar sensor, then the frequency stability is improved, but the FIT rate (Failure In Time) increases significantly, consuming a large portion of the available FIT budget
Solution Approach 1:
The patent extracts the clock pulse generation function from a single quartz oscillator and distributes it across multiple independent clock pulse generators. This extraction eliminates the single point of failure associated with one quartz oscillator while maintaining frequency stability through the redundant generators, thereby reducing the FIT rate contribution.
Solution Approach 2:
The system changes the parameter of clock pulse generation from a single source to multiple sources. By implementing multiple clock pulse generators with potential phase shifts, the system maintains frequency stability while distributing the failure risk, thus improving reliability without sacrificing frequency precision.
3Reliability
If multiple clock pulse generators are implemented with multiplexers for redundant frequency supply, then the reliability and emergency operation capability are improved, but the device complexity increases
Solution Approach 1:
The multiplexers are designed to perform multiple functions: they can switch between different clock pulse generators, route signals to different sub-sensors, and maintain system operation during failures. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing device complexity while improving reliability.
Solution Approach 2:
The patent merges the clock pulse generation and distribution functions into an integrated system where multiple clock pulse generators and multiplexers work together as a unified redundant structure. This combining approach manages complexity by creating a modular system where components serve both redundancy and signal distribution purposes simultaneously.
4Productivity
If all high-frequency components operate simultaneously during normal operation, then the productivity and performance of the radar sensor system is improved, but the loss of time for system deactivation upon failure increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring redundant clock pulse generators and multiplexers before any failure occurs. The switching mechanism is prepared in advance, allowing for immediate failover to backup components without requiring time-consuming reconfiguration or deactivation sequences, thus minimizing loss of time while maintaining high performance during normal operation.
Data Source
AI summary
A radar sensor system for transmitting and receiving radar waves. The system includes a first sub-sensor having a first antenna and a first antenna control for operating the first antenna, and a second sub-sensor including a second antenna and a second antenna control for operating the second antenna. The system further includes a frequency-generating device having a clock pulse generator for generating a usable frequency and having a control unit for actuating and controlling the first antenna control, the second antenna control and the frequency-generating device, the frequency-generating device having a first clock pulse generator and a second clock pulse generator, the first clock pulse generator and the second clock pulse generator being able to be connected via at least two multiplexers to the first antenna control and the second antenna control for the supply of a usable frequency in each case.