CW Frequency Diverse Array Sensing for Unambiguous Azimuth and Range
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Solution Overview
Problem
Existing radar and sonic detection technologies face limitations in determining the unambiguous angle and range of reflective objects, particularly in systems that do not require steerable antennas, and there is a need for more efficient and cost-effective methods.
Innovation Solution
A Continuous Wave Frequency Diverse Array (CW-FDA) detector system using an array of transmitter elements with different frequency signals to generate transmission patterns that enable unambiguous determination of azimuth and range through constructive interference patterns, allowing for fixed geometry receivers and lower peak power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar systems use steerable receivers to determine azimuth and range, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical steerable receiver system with a fixed geometry receiver array. Instead of mechanically steering a single receiver to track targets, the system uses multiple fixed receivers with different frequency transmissions to achieve the same azimuth and range determination through signal processing and frequency diversity
Solution Approach 2:
The patent changes the frequency parameter transmitted by each receiver element according to a specific frequency diverse array pattern. This frequency modulation creates unique transmission patterns that enable unambiguous target localization without mechanical steering, resolving the contradiction between measurement precision and device complexity
2Reliability
If pulsed radar systems are used to determine range and angle, then detection capability is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic frequency modulation across the receiver array elements, creating repeating transmission patterns that sweep through different spatial regions. This periodic frequency diversity allows continuous wave operation with lower peak power while maintaining detection capability through the time-varying frequency pattern
Solution Approach 2:
The system uses continuous wave transmissions instead of pulsed operation, maintaining continuous useful action for detection. The frequency diverse array creates time-varying transmission patterns that provide continuous coverage of the field of view, eliminating the need for high peak power pulses while sustaining detection reliability
3Measurement precision
If frequency diverse array patterns are used to constrain target location, then measurement precision is improved, but transmission complexity increases
Solution Approach 1:
The patent segments the frequency spectrum across different receiver array elements, with each element transmitting at a distinct frequency or frequency pattern. This frequency segmentation creates spatially distributed transmission patterns that constrain target location to specific regions, achieving high localization precision through frequency division rather than complex temporal control
Solution Approach 2:
The system pre-configures the frequency diverse array transmission patterns before operation, establishing deterministic frequency assignments to each receiver element. This preliminary configuration creates predictable transmission patterns that simplify real-time control while maintaining the ability to precisely constrain target locations through the pre-established frequency-spatial relationships
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 unambiguous determination of the angle and range of reflective objects within a field of view without the need for costly steerable receivers, reducing system complexity and cost while maintaining high detection accuracy.
Implementation Method 1
The spacing of the transmitter elements and the frequencies provided thereto, are such as to generate: a first transmission pattern, that: exhibits a deterministic pattern of constructive interference
Implementation Method 2
A receiver arranged to receive returned signals reflected from a reflective object resulting from transmission by the CW-FDA Transmitter
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
A continuous wave, frequency diverse array (FDA) detector, transmitter, receiver and/or method are disclosed. The frequencies can be radio waves or sonic waves. Different frequencies are applied to each transmitter element, to generate transmissions schemes with repeating patterns of constructive interference (e.g. each pattern may be a spiral). The patterns differ (e.g. opposite spiral directions to help determine azimuth, or different spiral rotation speeds to help determine range), to a sufficient extent that from the timing of signal reflected back as a result of each one, the azimuth and/or range of an object can be determined, irrespective of where the object/target is in the field of view. Use of continuous wave transmissions enables lower transmission powers and/or avoids requiring an expensive beam-steering transmitters or receivers.