Ship-Based Over-the-Horizon Radar with Digital Beamforming
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Solution Overview
Problem
Existing over-the-horizon (OTH) radar systems are limited by massive transmit and receive antenna structures that can only be installed on large tracts of flat land, restricting their mobility and coverage areas, whereas airborne and ship-based line of sight radars offer limited persistent coverage.
Innovation Solution
A ship-based OTH radar system with a transmit and receive antenna configuration that uses a reflective ground screen and advanced digital beamforming techniques to compensate for ship motion, allowing for real-time adaptive selection of radar signal characteristics based on ionospheric conditions and ship position, enabling persistent wide-area surveillance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If massive transmit and receive antenna structures are used for OTH radar, then surveillance coverage area is improved, but mobility and ease of deployment deteriorate
Solution Approach 1:
The radar system is divided into separate transmit and receive modules that can be independently deployed on different ships. Each module contains its own antenna and ground screen, allowing modular deployment and reconfiguration based on operational requirements while maintaining large effective aperture for wide coverage.
Solution Approach 2:
The sea surface is utilized as a natural reflective ground screen, eliminating the need for large artificial ground structures. This intermediary medium (sea) provides the necessary reflective properties for OTH radar operation while enabling mobile deployment on ships without requiring land-based installations.
2Duration of action of stationary object
If land-based OTH radar systems are deployed, then persistent wide-area coverage is improved, but adaptability to different regions deteriorates
Solution Approach 1:
The radar system transitions from static land-based installation to dynamic ship-based deployment. Ships can move to different locations to provide persistent coverage over changing target areas, and the system can reconfigure transmit and receive antenna positions and orientations to adapt to different operational regions and ionospheric conditions.
Solution Approach 2:
The ship-based platform provides universal deployment capability across different geographic regions and operational environments. The same system can be deployed in various ocean areas, providing adaptable wide-area surveillance for different missions including anti-access/area denial, maritime security, and air surveillance over water.
3Ease of operation
If ship-based platform is used, then mobility is improved, but stability and reliability deteriorate due to ship motion
Solution Approach 1:
The system incorporates real-time feedback mechanisms that monitor ship motion and dynamically adjust beamforming parameters, antenna orientations, and signal processing algorithms to compensate for platform movement. This active compensation maintains signal stability and detection reliability despite the mobile ship-based platform.
Solution Approach 2:
The system replaces mechanical stabilization structures with digital signal processing and software-based beamforming techniques. Advanced digital beamforming algorithms compensate for ship motion effects computationally, eliminating the need for heavy mechanical stabilization systems while maintaining signal reliability.
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 ship-based OTH radar system provides mobile, persistent, and wide-area air and ship surveillance across large ocean expanses and in anti-access/area denial environments, overcoming the limitations of land-based systems by utilizing the sea as a reflective medium and advanced signal processing techniques.
Implementation Method 1
transmit radar signals towards the Ionosphere to refract off the Ionosphere towards a selected target area
Implementation Method 2
reflect off the one or more objects within the selected target area to be received by the receive ship
Implementation Method 3
utilizing the sea as a reflective medium
Data Source
AI summary
A ship-based over-the-horizon (OTH) radar system provides mobile, persistent, wide-area air and ship surveillance across large ocean expanses and in anti-access/area denial (A2AD) environments. A transmit ship may include a log-periodic antenna (LPA) array adapted for use on a ship and a receive ship may include a plurality of monopole or dipole whip antennas. The transmit/receive antenna is fronted by a ground screen, which can be sized taking into account the sea as a naturally reflective surface. The transmit/receive ship can include advanced software to compensate for ship movement and synthetic aperture radar (SAR) techniques can be employed to includes the effective size of the radar receiver aperture. A modular design, using standard commercial container ships and shipping containers, allows for rapid deployment/stowage of radar equipment. Related methods are also described.