Virtual Antenna Extension for HFSWR Resolution
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Solution Overview
Problem
High frequency surface wave radar systems face a challenge in reducing the physical size of the receiving array while maintaining performance and resolution, as smaller arrays compromise the overall performance, particularly the resolution of the radar.
Innovation Solution
The system employs multiple transmitters to create a virtual receiving antenna array by transmitting sequences of radar pulses separated by specific round-trip travel times, allowing the receiver circuitry to distinguish and concatenate returns, effectively increasing the array width beyond the physical array size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a smaller receiving array is employed, then the physical size of the radar is reduced, but the resolution and overall performance of the radar deteriorates
Solution Approach 1:
The patent transitions from a two-dimensional physical array arrangement to a four-dimensional virtual array by adding temporal dimension through pulse sequencing. Multiple transmitters transmit pulses at different times, creating a virtual array that extends in both spatial and temporal dimensions, effectively increasing the aperture without adding physical antennas.
Solution Approach 2:
The patent creates a virtual copy of the receiving array by using multiple transmitters that replicate the receiving array's functionality. Each transmitter acts as a copy of the receiving array, and by combining their outputs through concatenation, a virtual array with enhanced resolution is formed without requiring additional physical receiving elements.
2Length of stationary object
If multiple transmitters are used to form a virtual array, then the array width is increased beyond physical limits, but the system complexity increases
Solution Approach 1:
The patent makes the transmitters multi-functional by having them serve both as transmitting elements and as virtual receiving elements. The same transmitters that send pulses are used to receive and process returns, eliminating the need for separate receiving array elements and reducing overall system complexity despite having multiple transmitters.
Solution Approach 2:
The patent uses periodic pulse transmission and reception cycles to manage system complexity. By transmitting pulses in sequences with specific timing intervals and receiving returns during designated periods, the system organizes the multiple transmitters in a time-division manner, making the complex multi-transmitter system manageable through structured temporal organization.
Data Source
AI summary
A high frequency surface wave radar (HFSWR) system with improved performance. Two or more transmitters including separate transmitting antennas (120, 122, 410) are used to improve the performance of the HFSWR over the performance of a comparable system with a single transmitter. In one embodiment, two transmitters are used, and configured to transmit pulses alternately, with a time interval of at least a round-trip travel time corresponding to a maximum target range between any pair of transmitted pulses. A physical receiving antenna array (130) includes a plurality of receiving antenna elements (135), and is connected to receiver circuitry configured to distinguish returns corresponding to pulses emitted by the different transmitters. The returns are concatenated in the receiver circuitry to achieve improved resolution.