Passive Coherent Location Radar Target Identification
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Solution Overview
Problem
Current radar systems face challenges in accurately and efficiently tracking and identifying target objects due to their monostatic nature, high-energy RF power requirements, and complexity in processing narrow, weak lobes of electromagnetic energy, which limits their ability to provide consistent and reliable identification, especially in environments where continuous tracking is necessary.
Innovation Solution
The implementation of Passive Coherent Location (PCL) technology, which operates as a bistatic or multistatic system using Continuous Wave (CW) or FM transmitter sources, allowing for high-rate target updates and enhanced detectability without the need for RF energy transmission, enabling accurate tracking and identification of targets through simultaneous processing of multiple objects and structural feature analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monostatic radar systems use pulse-based scanning to detect and track targets, then target detection capability is achieved, but continuous tracking is compromised due to blind windows between pulses and scans
Solution Approach 1:
The patent transitions from periodic pulse-based scanning to continuous wave transmission, eliminating the periodic blind windows between pulses. The continuous transmission allows uninterrupted target illumination and signal reception, enabling continuous tracking without gaps that would compromise reliability.
Solution Approach 2:
The system maintains continuous electromagnetic energy transmission and reception, ensuring uninterrupted target illumination and data collection. This continuous operation eliminates the idle periods inherent in pulse-based systems, allowing consistent tracking updates and improving both reliability and productivity simultaneously.
2Measurement precision
If microwave radar systems use narrow beamwidths for precise target location, then spatial resolution is improved, but the number of narrow lobes increases complexity in processing scattered energy
Solution Approach 1:
The patent changes the frequency parameter from microwave to VHF, which fundamentally alters the scattering characteristics. At VHF frequencies, the wavelength is longer, reducing the number of narrow lobes scattered by target structures while maintaining sufficient measurement precision for target identification and tracking.
Solution Approach 2:
The system extracts only the most significant scattering lobes at VHF frequencies rather than processing all narrow lobes present at microwave frequencies. This selective approach reduces computational complexity by focusing on dominant scattering features that provide sufficient target characterization.
3Measurement precision
If JEM and ISAR techniques are used to create target signatures, then target identification capability is achieved, but the systems require complex calculations at intervals that allow substantial target movement
Solution Approach 1:
The patent changes the operating frequency to VHF and uses continuous wave transmission, which provides uninterrupted target illumination. This allows signature calculations to be performed at much higher update rates compared to pulsed microwave systems, reducing target movement between measurements while simplifying the overall system approach.
Solution Approach 2:
Continuous wave transmission enables uninterrupted collection of scattering data, allowing signature calculations to be performed continuously at high rates. This eliminates the intermittent measurement approach of pulsed systems, reducing target movement between measurements and enabling more frequent, accurate identification updates.
4Use of energy by moving object
If monostatic radar uses high-energy RF power transmission for target detection, then detection range is improved, but system construction and operation costs increase
Solution Approach 1:
The patent uses passive VHF transmitters (such as TV and FM broadcast stations) as intermediary signal sources instead of requiring active high-power radar transmitters. These existing transmitters illuminate targets passively, eliminating the need for expensive high-energy RF power transmission equipment while maintaining adequate detection capabilities.
Solution Approach 2:
The system exploits existing VHF transmission infrastructure (broadcast stations, other VHF sources) to provide target illumination. These external sources serve the radar function without requiring the system to generate its own high-power signals, significantly reducing construction and operational costs while maintaining detection effectiveness.
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
PCL technology provides high-velocity accuracy and resolution, reduces system costs, and enhances detectability by up to two orders of magnitude, allowing for real-time tracking and identification of targets with increased accuracy and reduced complexity, particularly suitable for covert surveillance and identification of aircraft and missiles.
Implementation Method 1
an antenna for receiving direct signals from the transmitters and reflected signals reflected by the target object
Implementation Method 2
By analyzing the time difference of arrival, Doppler shift, and various other changes in the reflected energy, the location and movement of the target object can be calculated
Data Source
AI summary
The present invention is directed to a system and method for the identification of a target object in PCL radar applications. The disclosed embodiments describe the systems and methods used in the identification of a target object from the collection of data representing specific target object features, such as velocity, altitude, fuselage length, wing length, or wing sweepback angle, and the comparison of selected target object features with a database of known aircraft features. The present invention also provides for the calculation of feature dimensions, such as the fuselage length, wing length, or wing sweepback angle from measurements associated with a peak signal lobe as a function of a bistatic aspect angle.