Distributed Aperture Automotive Radar Coherent Virtual Array
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Solution Overview
Problem
Existing automotive radar systems face challenges in achieving high angular resolution without increasing the physical size of the radar, which is constrained by design and integration requirements in vehicles.
Innovation Solution
A distributed aperture radar system that combines multiple independent, small-aperture radars without requiring a shared common local oscillator signal, using signal processing techniques to determine and compensate for frequency and phase offsets between radars, thereby forming a large coherent virtual aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large aperture radar is used to achieve high angular resolution, then angular resolution is improved, but the physical size of the radar increases
Solution Approach 1:
The patent divides a large aperture radar system into multiple independent small-aperture radar devices distributed across different locations. Each device operates autonomously with its own local oscillator, and their signals are combined through processing to achieve the angular resolution equivalent of a large aperture without requiring a physically large radar structure.
Solution Approach 2:
The patent transitions from a single-dimension physical aperture constraint to a multi-dimensional solution by distributing radar devices across spatial locations and combining their virtual apertures through signal processing. This creates a virtual large aperture in the signal domain that overcomes the physical size constraints in the spatial domain.
2Measurement precision
If distributed radars share a common local oscillator signal to form a large virtual aperture, then angular resolution is improved, but system complexity and cost increase
Solution Approach 1:
Each distributed radar device generates its own local oscillator signal independently without requiring a shared common LO. The system achieves coherence through signal processing techniques that estimate and compensate for frequency and phase offsets between the independent oscillators, eliminating the need for complex hardware modifications to share oscillators.
Solution Approach 2:
The patent introduces signal processing algorithms as an intermediary that bridges the gap between independent local oscillators. These algorithms estimate frequency and phase offsets and apply corrections to the received signals, enabling coherent combination of signals from radars with independent oscillators without requiring direct hardware coupling.
3Measurement precision
If distributed radars cross-correlate or mix target return signals to form a large virtual aperture, then angular resolution is improved, but system complexity and cost increase
Solution Approach 1:
The patent employs feedback mechanisms where the system estimates frequency and phase offsets by analyzing the relationship between transmitted and received signals. This feedback information is then used to correct subsequent signal processing operations, enabling coherent combination without requiring complex pre-configured cross-correlation hardware.
Solution Approach 2:
The patent changes the approach from fixed hardware-based signal mixing to flexible software-based parameter estimation and compensation. By dynamically estimating frequency and phase parameters and adjusting the signal processing accordingly, the system achieves virtual aperture formation with independent oscillators using standard radar signal processing techniques.
Data Source
AI summary
A distributed radar system, apparatus, architecture, and method is provided for coherently combining physically distributed radars to jointly produce target scene information in a coherent fashion without sharing a common local oscillator (LO) reference by configuring a first (slave) radar to apply fast and slow time processing steps to target returns generated from a second (master) radar, to compute an estimated frequency offset and an estimated phase offset between the first and second radars based on information derived from the fast and slow time processing steps, and to apply the estimated frequency offset and estimated phase offset to generate a bi-static virtual array aperture at the first radar that is coherent in frequency and phase with a mono-static virtual array aperture generated at the second radar, thereby achieving better sensitivity, finer angular resolution, and low false detection rate.