Distributed Radar Phase Correction for Accurate Azimuth Estimation
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Solution Overview
Problem
Existing radar systems face challenges in achieving accurate azimuth estimation due to phase errors caused by variations in wiring and circuit manufacturing delays, which restrict the arrangement of virtual antennas and reduce aperture length.
Innovation Solution
A radar system with spatially separated radars uses a local oscillator to generate a reference signal, incorporating RF and BB circuits to process signals, and includes a processor for calculating delay times and correcting phase errors based on these measurements, allowing non-overlapping antenna arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virtual antennas are arranged at overlapping positions to correct phase errors, then azimuth estimation accuracy is improved, but aperture length is reduced and design freedom is restricted
Solution Approach 1:
The patent applies preliminary action by calculating and correcting phase errors due to delay time differences before performing azimuth estimation. The processor calculates delay times between signals from spatially separated radars, computes phase errors based on these delay times, and corrects the phase of IF signals before combining them for azimuth estimation. This preliminary phase correction enables accurate azimuth estimation without requiring overlapping virtual antenna positions, thus maintaining aperture length and design freedom.
2Measurement precision
If virtual antennas are arranged at overlapping positions to correct phase errors, then azimuth estimation accuracy is improved, but design freedom is restricted
Solution Approach 1:
The patent applies preliminary action by calculating and correcting phase errors due to delay time differences before performing azimuth estimation. The processor calculates delay times between signals from spatially separated radars, computes phase errors based on these delay times, and corrects the phase of IF signals before combining them for azimuth estimation. This preliminary phase correction enables accurate azimuth estimation without requiring overlapping virtual antenna positions, thus maintaining aperture length and design freedom.
3Adaptability or versatility
If phase errors are not corrected, then design freedom is maintained, but azimuth estimation accuracy deteriorates
Solution Approach 1:
The patent applies feedback by using measured delay time differences to calculate phase errors and apply corrective adjustments. The processor measures the delay time differences between signals from spatially separated radars, calculates the resulting phase errors, and applies phase correction to the IF signals. This feedback-based correction mechanism maintains design freedom by allowing spatially separated radar arrangements while improving azimuth estimation accuracy through adaptive phase compensation.
4Device complexity
If spatially separated radars are used without phase correction, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies feedback by using measured delay time differences to calculate phase errors and apply corrective adjustments. The processor measures the delay time differences between signals from spatially separated radars, calculates the resulting phase errors, and applies phase correction to the IF signals. This feedback-based correction mechanism maintains design freedom by allowing spatially separated radar arrangements while improving azimuth estimation accuracy through adaptive phase compensation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the phase parameter of IF signals based on calculated delay time differences. The processor calculates delay times between signals from spatially separated radars, determines phase errors as a function of these delay times and signal frequency, and applies phase correction by modifying the phase parameter of the IF signals before combining them for azimuth estimation.
Data Source
AI summary
A radar system includes: radars arranged in a spatially separated manner and including transmission and reception antennas for a radar signal; a local oscillator for providing a reference signal; and a processor for estimating an azimuth of an object. Each radar includes: an RF circuit for processing a signal in a same frequency band as the radar signal to generate an IF signal; and a BB circuit for processing the IF signal. The processor includes: a delay time calculation unit for calculating delay times of the RF circuit and BB circuit between radars based on a measurement result of the object; a phase error correction unit for correcting a phase of the IF signal based on the delay times; and an azimuth estimation unit for estimating the azimuth of the object based on a corrected IF signal.