Phased Array Antenna Direction Finding for Rescue Beacons
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Solution Overview
Problem
Conventional direction finding systems for mobile applications, such as electronic warfare and search and rescue, are large, expensive, and require multiple antenna sets to provide accurate and unambiguous readings, often needing multiple input pulses.
Innovation Solution
A portable direction finding system utilizing a single phased array antenna and boom assembly with two dipole elements, which is lightweight, inexpensive, and capable of making direction-finding determinations based on continuous beacon outputs, incorporating an electronic compass and digital signal processing for high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multi-element Yagi antenna and boom assembly is used, then directional capability is achieved, but device size and complexity increase
Solution Approach 1:
The patent combines multiple antenna elements into a single integrated phased array antenna assembly. The array processor integrates signal processing functions that were previously distributed across separate antenna elements and boom assemblies, creating a unified system that maintains directional capability while reducing overall complexity.
Solution Approach 2:
The phased array antenna assembly is designed to perform multiple functions: signal reception, direction finding, and ambiguity resolution. The array processor handles various signal processing tasks including phase comparison, amplitude measurement, and position determination, eliminating the need for separate specialized components.
2Measurement precision
If two or more sets of antennas are used to resolve ambiguity, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple antenna sets into a single phased array system. The array processor integrates the signal processing capabilities that would otherwise require separate receiver subsystems, achieving the same measurement accuracy with reduced complexity.
Solution Approach 2:
The array processor acts as an intermediary that processes signals from the phased array elements to determine direction of arrival. This central processing unit resolves ambiguities by comparing phase and amplitude information across multiple elements, eliminating the need for multiple independent receiver subsystems.
3Measurement precision
If multiple input pulses are required for direction finding, then measurement accuracy is improved, but time consumption increases
Solution Approach 1:
The phased array antenna assembly continuously processes incoming signals to determine direction of arrival. The array processor continuously compares phase and amplitude information across multiple elements, providing real-time direction finding without requiring discrete pulse sequences or multiple input pulses.
Solution Approach 2:
The system performs preliminary signal processing by continuously monitoring and storing phase and amplitude information from multiple antenna elements. This preliminary processing enables rapid direction determination without requiring multiple sequential input pulses, as the necessary data is already prepared and ready for immediate analysis.
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
The system provides high accuracy and sensitivity in determining the direction of arrival of signals from rescue beacons, enabling precise location determination with reduced complexity and cost, and is adaptable for use with both 121.5 MHz and 406 MHz frequencies.
Implementation Method 1
a phased array antenna and boom assembly with two dipole elements... capable of making direction-finding determinations based on continuous beacon outputs
Implementation Method 2
utilization of information from a phased array antenna and boom assembly... provides high accuracy lines of bearings from the direction of arrival of an electrical signal
Data Source
AI summary
Apparatuses and methods are disclosed that allow for the detection, identification and direction finding of search and rescue beacons in a variety of environments. The techniques may be used to identify a line of bearing (LOB) to 121.5 MHz rescue beacons found in aircraft (ELTs), marine beacons (EPIRBs), and personal locator beacons (PLBs). Multiple lines of bearing may be used to geo-locate a target emitter if so desired. The methods may utilize, for example, a handheld device that is designed for search and rescue activity. Additionally, this device may be able to decode a 406 MHz frequency beacon that communicates with the satellite system that is controlled by COSPAS SARSAT. This constellation of rescue satellites coordinates the location of 406 MHz rescue beacons.