Phase-Weighted Coherent Integration for Moving Target Detection
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Solution Overview
Problem
Conventional coherent integration techniques in target observation devices, such as sonars and radars, degrade when there is relative motion between the observation device and the target, leading to a reduction in signal component quality and process gain.
Innovation Solution
An observation signal processing apparatus that successively transmits pulse signals modulated by multiple carrier waves, captures reflected signals, performs correlative detection, and applies phase-weighted coherent integration to maintain high signal quality even with relative motion, using a phase correction amount calculated based on estimated relative speed to adjust the integration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional coherent integration technique is applied to reflected wave from target, then signal-to-noise ratio is improved by averaging observation values, but process gain degrades when there is relative speed between observation device and target
Solution Approach 1:
The patent applies preliminary action by calculating and storing phase correction amounts based on estimated relative speeds before coherent integration is performed. The system pre-calculates phase corrections for multiple possible relative speeds and stores them in memory, then retrieves and applies the appropriate correction during integration. This preliminary preparation eliminates the degradation caused by relative motion between the observation device and target, maintaining high process gain while preserving the signal-to-noise ratio improvement from coherent integration.
2Measurement precision
If coherent integration is performed on reflected wave from moving target, then observation values are averaged to improve signal quality, but signal component degrades due to relative speed effect
Solution Approach 1:
The patent implements feedback by using estimated relative speed information to dynamically adjust the phase correction applied during coherent integration. The system estimates the relative speed between the observation device and target, retrieves corresponding phase correction amounts from pre-calculated tables, and applies these corrections to compensate for the relative motion effect. This feedback mechanism preserves the signal component while maintaining the signal quality improvement from averaging observation values.
Data Source
AI summary
An observation signal processing apparatus transmits a pulse signal as a search signal, generates an observation value based on a reflected signal against a target and a delay modulation pulse signal, and performs coherent integration on the observation value to output an integration value. The apparatus includes a section for determining a coherent integration count, a section for transmitting pulse signals equivalent to the coherent integration count, a section for calculating a phase correction amount based on an estimated relative speed, and a section for performing phase-weighted coherent integration on observation values for the number of times equivalent to the coherent integration count based on the phase correction amount.