Dual Receive Paths for FMCW Radar Long-Range Detection
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Solution Overview
Problem
Radar sensors face challenges in reliably receiving and processing reflected signals from distant objects due to aggressive signal power decay and noise interference, particularly in automotive applications where multiple sensors are used, leading to difficulties in detecting far-away objects below the detection threshold.
Innovation Solution
A receive path arrangement for radar sensors featuring multiple paths, including a first receive path for lower beat frequencies and a second receive path with a filter and amplifier configuration that attenuates low beat frequencies and amplifies higher beat frequencies, allowing for greater signal amplification and digital signal processing across different frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single receive path is used to process all reflected radar signals, then the device complexity is low, but the measurement precision and reliability of detecting distant objects deteriorates due to signal power decay and noise interference
Solution Approach 1:
The receive path is divided into multiple parallel paths (first receive path and second receive path), each configured to process different frequency bands of reflected radar signals. The first receive path handles lower beat frequencies while the second receive path handles higher beat frequencies, allowing optimized processing for each band and improving overall detection precision without requiring a single complex path to handle all frequencies equally
2Measurement precision
If signal amplification is increased to overcome signal power decay from distant objects, then the measurement precision improves, but noise interference also increases and affects detection reliability
Solution Approach 1:
Different receive paths are assigned different filter characteristics and amplification levels tailored to their specific frequency bands. The second receive path, which processes higher beat frequencies from distant objects, applies targeted amplification only to its frequency range, thereby improving signal detection capability while minimizing the amplification of out-of-band noise interference
3Adaptability or versatility
If multiple receive paths with different frequency bands are used to detect objects at varying distances, then the measurement precision and detection range improve, but the device complexity increases due to multiple filters and amplifiers
Solution Approach 1:
The signal processing system is segmented into multiple receive paths, each with dedicated filters and amplifiers for specific frequency bands. This segmentation allows the system to detect objects at varying distances effectively, as each path can be optimized for its designated range, while the modular architecture keeps the overall complexity manageable through functional decomposition
Solution Approach 2:
The multiple receive paths share common functional blocks such as the analog-to-digital converter and digital signal processor, allowing these components to serve multiple functions across different frequency bands. This multi-functionality approach increases detection versatility while reducing the total component count and system complexity
Data Source
AI summary
A receive path arrangement of a radar sensor of FMCW type comprising a first and second receive path configured to receive reflected radar signals for detection and ranging of objects in a space around the radar sensor;the first receive path configured to provide reflected radar signals between a first and second beat frequency to a first analogue to digital converter for subsequent digital signal processing and wherein;the second receive path includes a second-receive-path filter configured to provide filtered signals by attenuation of the reflected radar signals having frequencies below an intermediate beat frequency, the intermediate beat frequency between the first and second beat frequencies, the second receive path further including a second-receive-path amplifier arrangement configured to provide amplified signals by amplification of the filtered signals and provide the amplified signals to a second analogue to digital converter for subsequent digital signal processing.