Bullet Detection Radar Using Matched Filter Doppler Correlation
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Solution Overview
Problem
Traditional radar systems, both pulsed and continuous-wave, face challenges in detecting and tracking bullets due to their speed and small size, requiring large, heavy, and complex systems for pulsed radar and struggling with range detection and doppler smear in continuous-wave radars.
Innovation Solution
A radar system utilizing a receive antenna and a set of matched filters to determine the Doppler shift correlation, allowing for the detection and estimation of a bullet's trajectory, speed, and point of origin through pre-stored Doppler shifts and azimuth-angle estimation algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pulsed radar is used to detect and track bullets, then detection capability is achieved, but the system becomes very large, heavy, and complex
Solution Approach 1:
The patent changes the operational parameters of the radar system by using continuous-wave transmission instead of pulsed transmission, and employs matched filter processing with pre-stored Doppler shift templates to detect bullets. This parameter change allows the system to achieve bullet detection capability with a smaller, lower-powered radar that is suitable for field deployment.
Solution Approach 2:
The patent replaces the complex pulsed radar system with a continuous-wave radar system using signal processing substitution. Instead of relying on high peak power and large aperture mechanical systems, the invention uses sophisticated signal processing techniques including matched filters and Doppler shift correlation to achieve detection with a simpler, more compact system.
2Power
If continuous-wave radar is used to transmit continuously, then more energy is placed on the target permitting lower-powered antenna, but range detection becomes difficult without sophisticated waveforms
Solution Approach 1:
The patent applies preliminary action by pre-storing Doppler shift templates that correspond to various bullet trajectories, speeds, and distances. These pre-computed templates are stored in memory and used during matched filter processing to quickly identify bullet returns without requiring complex real-time waveform generation or processing.
Solution Approach 2:
The patent uses copying by creating and storing template signals that represent expected Doppler shifts from bullets at various parameters. These templates are copies of expected signal patterns that are correlated with the received signal to detect and characterize bullet targets, avoiding the need for complex real-time signal synthesis.
3Device complexity
If standard doppler-processing detection methods are used in continuous-wave radar, then processing is simplified, but detection of bullets is inadequate due to doppler smear
Solution Approach 1:
The patent applies segmentation by dividing the Doppler processing into multiple discrete matched filters, each tuned to a specific Doppler shift corresponding to a particular bullet speed or distance. Instead of using a single broad Doppler processor, the system segments the detection space into multiple narrow bands, each handled by a dedicated matched filter that can accurately detect bullets with specific trajectory parameters.
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
Enables effective detection and tracking of bullets in-flight, determining the shooter's position with a smaller, lower-powered radar system, overcoming the limitations of traditional radar technologies.
Implementation Method 1
a receive antenna configured to receive a receive signal reflected from a ballistic target, the receive signal exhibiting a Doppler shift according to motion of the ballistic target
Data Source
AI summary
A radar system, comprising: a receive antenna configured to receive a receive signal reflected from a bullet, the receive signal exhibiting a Doppler shift according to the motion of the bullet; and a detector implementing a set of matched filters each configured to determine a measure of correlation between the Doppler shift of the receive signal and one of a set of pre-stored Doppler shifts, wherein each of the pre-stored Doppler shifts respectively represents the Doppler shift of a bullet passing the antenna at a different speed or a distance of a point of closest approach.