Passive Coherent Location Tracking for UAVs
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Solution Overview
Problem
Current tracking technologies face challenges in reliably detecting and tracking Unmanned Aerial Vehicles (UAVs) and other aerial vehicles, especially in controlled airspace, due to limitations in passive coherent location systems, including stealth capabilities, signal interference, and ground clutter, which affect accuracy and detection range.
Innovation Solution
The integration of enhanced Passive Coherent Location (PCL) systems with conventional automatic dependent surveillance broadcast (ADS-B), transponder multilateration, broadband emitter multilateration, primary and secondary radar, and the use of advanced signal processing techniques to improve tracking and identification capabilities, including narrowband pre-detection signal processing and co-channel interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If passive coherent location systems are used to track UAVs, then detection capability is improved, but detection accuracy deteriorates due to stealth capabilities and signal interference
Solution Approach 1:
The system divides the tracking task into multiple independent PCL subsystems, each using different transmitter sources (TV towers, radio stations, cellular base stations). Each subsystem processes signals independently and contributes to the overall track, allowing the system to overcome the stealth capabilities of individual targets through multiple observation angles and frequencies.
Solution Approach 2:
The PCL system is designed to work with multiple types of transmitters simultaneously (terrestrial TV, radio, cellular), making it universally applicable to various UAV types and operational scenarios. This multi-functionality allows the system to adapt to different environmental conditions and maintain detection accuracy across diverse scenarios.
2Length of stationary object
If conventional radar systems are used, then tracking range is improved, but system complexity increases due to collocated transmitters and receivers
Solution Approach 1:
The system uses third-party transmitters (TV towers, radio stations, cellular base stations) as intermediaries to illuminate targets. These existing infrastructure elements serve as the illumination source, eliminating the need for dedicated radar transmitters and reducing system complexity while maintaining effective tracking range.
Solution Approach 2:
The PCL system leverages existing communication infrastructure that already provides the necessary electromagnetic radiation for tracking. By repurposing these existing transmitters for surveillance purposes, the system avoids the complexity of deploying and maintaining dedicated radar transmitters while achieving comparable or superior performance.
3Measurement precision
If multiple transmitters and receivers are employed to improve track accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses a single receiver that processes signals from multiple transmitter sources simultaneously. This multi-functional approach allows the receiver to extract tracking information from diverse transmitter types (TV, radio, cellular) without requiring separate receiver systems, thereby improving track accuracy through multiple measurements while avoiding the complexity of multiple dedicated receivers.
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 real-time tracking and identification of various aircraft and UAVs with enhanced accuracy and reliability, effectively overcoming stealth capabilities and signal interference, and providing comprehensive surface track pictures with improved update rates and latency.
Implementation Method 1
measures the time difference of arrival between the signal arriving directly from the transmitter and the signal arriving via reflection from the object. This allows the bi-static range of the object to be determined.
Implementation Method 2
In addition to bi-static range, passive radar will typically also measure the bi-static Doppler shift of the echo and also its direction of arrival. These allow the location, heading and speed of the object to be calculated.
Implementation Method 3
comparing the received transmissions to determine a frequency-difference-of-arrival thereby establishing a track or tracks for the object or objects
Data Source
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AI summary
A system and technique is described which has the capability to track and identify, in real time, various aircraft (100) and objects including Unmanned Aerial Vehicles (UAVs), Unmanned Combat Aerial Vehicles (UCAVs), and Micro Aerial Vehicles (MAVs). The system uses a combination of techniques including conventional automatic dependent surveillance broadcast (ADS-B) (110, 150, 200), transponder multilateration, broadband emitter multilateration, primary and secondary radar, and passive coherent location (400, 450, 500). A series of enhancement to conventional passive coherent location are described.