FMCW Radar NLOS Detection Using Clutter Signatures
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Solution Overview
Problem
Existing object detection systems in autonomous vehicles and Automated Driver Assist Systems face challenges in accurately detecting objects in non-line-of-sight (NLOS) areas due to obstructions like buildings and trees, which hinder reliable and flexible object detection capabilities.
Innovation Solution
The implementation of a radar system using a frequency-modulated carrier-wave (FMCW) scheme with steerable beams and frequency-hopping signals, allowing for the detection of objects by analyzing reflections and deflections across obstructed paths, enabling accurate range and velocity calculations even in NLOS conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional radar systems are used for object detection, then line-of-sight detection is achieved, but non-line-of-sight detection capability is insufficient
Solution Approach 1:
The radar system segments the detection space into line-of-sight (LOS) and non-line-of-sight (NLOS) regions. By using multiple transmit antennas and receive antennas, the system creates separate detection channels that can independently analyze reflections from different paths, enabling reliable detection in both LOS and NLOS conditions simultaneously
Solution Approach 2:
The patent introduces intermediate reflection surfaces (such as buildings, walls, or other objects) as mediators to enable NLOS detection. The radar system detects objects by analyzing signals that reflect off these intermediate surfaces, allowing detection of targets that are not directly visible to the radar antenna
2Measurement precision
If FMCW signals with frequency-hopping are used, then range and velocity detection accuracy is improved, but signal processing complexity increases
Solution Approach 1:
The radar system employs periodic frequency-hopping patterns in its FMCW signals, where the frequency transitions follow a predetermined periodic sequence. This periodic structure simplifies the correlation processing required to detect reflected signals, as the receiver can use matched filtering techniques that exploit the known periodic frequency pattern to accurately determine range and velocity while managing computational complexity
Solution Approach 2:
The system dynamically changes signal parameters (frequency, modulation depth, pulse duration) based on detection requirements. By adjusting these parameters adaptively, the system optimizes the balance between measurement precision and processing complexity for different operational scenarios
3Area of stationary object
If steerable beams are implemented, then detection coverage area is expanded, but system complexity increases
Solution Approach 1:
The patent combines multiple fixed antennas into a phased array configuration, merging their individual detection capabilities into a unified steerable beam system. By coherently combining signals from multiple antennas with controlled phase differences, the system achieves electronic beam steering without mechanical movement, expanding coverage area while keeping the structure relatively simple
Solution Approach 2:
The steerable beam system serves multiple functions: it can electronically scan different directions, adjust beam width, and simultaneously monitor multiple sectors. This multi-functionality allows a single antenna array to replace what would otherwise require multiple fixed radar units, expanding coverage while managing system complexity
4Adaptability or versatility
If multi-path transmission analysis is performed, then NLOS object detection is enabled, but clutter interference increases
Solution Approach 1:
The radar system uses feedback from the received multi-path signals to identify and characterize reflection paths. By analyzing the timing, amplitude, and phase of returned signals, the system builds a model of the environment's reflection characteristics and uses this feedback to distinguish between useful NLOS targets and harmful clutter, adaptively adjusting detection parameters to suppress interference
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 enhances the ability to detect objects in dynamic environments by providing reliable and flexible object detection capabilities, improving safety and accuracy in autonomous driving scenarios by effectively handling multi-path transmissions and clutter interference.
Implementation Method 1
a radar system uses a frequency-modulated carrier-wave (FMCW) scheme with steerable beams and frequency-hopping signals, allowing for the detection of objects by analyzing reflections and deflections across obstructed paths
Implementation Method 2
enabling accurate range and velocity calculations even in NLOS conditions
Data Source
AI summary
Radar systems and methods of using the same for detecting objects in non-line-of-sight (“NLOS”) areas are disclosed. In various embodiments, the disclosed radar systems and methods use a clutter signature to determine a location and motion of an object. The disclosed radar systems may include a sounding signal module for transmitting a sounding signal to determine a clutter signature; a radar controller generating, controlling, and interpreting an object detection signal; a transmit antenna unit coupled to the radar controller, adapted to transmit the object detection signal; a receive antenna unit coupled to the radar controller, adapted to receive a return object detection signal; and/or a non-line of sight module coupled to the transmit antenna unit and the receive antenna unit adapted to determine a location of a detected object.