A method for implementing a relocatable Over-The-Horizon-Radar (OTHR) including transmitting mutually orthogonal signals on each of a plurality of antenna elements of a transmitting system, and receiving and decoding the signals at a plurality of receiving systems to synthesize beams from the orthogonal signals. Each receiving system has a plurality of antenna elements fewer in number than the plurality of antenna elements of said transmitting system. The method includes connecting as a network the transmitting system, the plurality of receiving systems, and a network controller.

System and methods for implementing a vector sensor array surface wave radar is provided. In one or more examples, the system can include a vector sensor array antenna that includes electromagnetic elements collectively configured to receive surface wave reflections generated by radar transmit antenna waves reflecting back from targets of interest. Once received by the vector sensor array, in one or more examples, the system can further include components that can process the incoming signal and use the incoming single to determine the location of one or more targets. In one or more examples, the vector surface array antenna can include three separate loop antennas that are arranged orthogonally to one another, and three dipole antennas that are arranged orthogonally to one another. In one or more examples, the vector surface array antenna can be configured to receive signals in the high frequency (HF) band.

An unmanned, autonomous, self-sustaining and self-repairable floating platform which is positioned at a fixed location within the sea, capable of constantly monitoring, without having to be removed, a specific maritime zone including a sea surface area and the aerial and underwater space pertaining to this sea surface area, the platform comprising telecommunication means adapted to exchange surveillance related information with a Command, Communication and Control center. The platform comprises a deck maintained well above sea surface through a connecting member with an underlying, fully or partially submerged, system of floaters and is equipped with a variety of sensors and surveillance systems such as radar, Li-dar, sonar, electromagnetic, unmanned vehicles (UAVs, UUVs and USVs), active and passive self-protection systems as well as research and rescue equipment. A mast having a substantial height (usually 40-50 m) and equipped with appropriate surveillance devices is mounted and ex-tends vertically upwardly the deck.

Described are a system and technique to mitigate the impacts of clutter in a radar system. The system and technique require only linear co-polarized measurements can be incorporated into the standard radar signal processing chain without slowing down radar performance.

A system and method for HF positioning characterizes the undulations of the ionosphere in real-time to determine the refraction altitude of a specific HF frequency at a specific time of day at a specific position. The system accounts for the seasonal (summer, winter) and daily (daylight, night, grey-line transition) variations of the ionosphere determining a highly accurate timing error relative to a timing reference. The system employs a novel approach that is capable of passively and accurately determining a position anywhere in the world without use of a GNSS signal receiving known-time transmissions of narrow band HF timing signals refracted via ionospheric skywave.

A buoy-type high-frequency ground wave radar system. A buoy platform is used as an offshore carrier of a ground wave radar. A sky wave emission subsystem is disposed on a shore base and emits a high-frequency electromagnet wave. After the high-frequency electromagnet wave is refracted by the ionosphere and is reflected by the sea surface, a sky wave signal is formed. An attitude measurement subsystem measures and acquires attitude data of the buoy platform in real time. A ground wave radar subsystem receives a ground wave signal by using the ground wave radar, and processes the signal to form a ground wave doppler spectrum. Simultaneously, the sky wave signal is received, ionosphere disturbance compensation is performed on the sky wave signal in a frequency domain and then the sky wave signal is processed to form a sky wave doppler spectrum. The ground wave radar subsystem reconstructs an actual geographic coordinate system according to the attitude data measured by the attitude measurement subsystem and then the ground wave or the sky wave doppler spectrum is used to inverse wind wave current data in the reconstructed actual geographic coordinate system. The sky wave emission subsystem and the ground wave radar subsystem carry out time synchronization by means of a GPS synchronization networking. The system can detect a sea region of any distance and is suitable for high sea detection.

A method for implementing a relocatable Over-The-Horizon-Radar (OTHR) including transmitting mutually orthogonal signals on each of a plurality of antenna elements of a transmitting system, and receiving and decoding the signals at a plurality of receiving systems to synthesize beams from the orthogonal signals. Each receiving system has a plurality of antenna elements fewer in number than the plurality of antenna elements of said transmitting system. The method includes connecting as a network the transmitting system, the plurality of receiving systems, and a network controller.

A phased array radar system comprises an array antenna including a plurality of selectively controllable transmit/receive (T/R) modules. One or more computer processors and associated memory devices are provided in communication with the plurality of T/R modules. The control processor is configured to cause the transmission of a first plurality of radio frequency (RF) pulses from a first portion of the array antenna, wherein the first plurality of pulses comprise at least two pulses having distinct center frequencies. A second plurality of RF pulses are transmitted from a second portion of the array antenna, wherein the second plurality of pulses comprise at least two pulses having distinct center frequencies. Received return signals originating from the first and second plurality of transmitted pulses are non-coherently integrated prior to the performance of target detection operations.

Methods and apparatus for a radar system having an array including a series of concentric rings of array elements, wherein the concentric rings that have a shape defined by respective ellipses that increase in size from a center that is common to the respective ellipses. The series of concentric rings can include multiple groups of the concentric rings, wherein the concentric rings in each successive group are larger in size than the concentric rings in the first group.

A buoy-type high-frequency ground wave radar system. A buoy platform is used as an offshore carrier of a ground wave radar. A sky wave emission subsystem is disposed on a shore base and emits a high-frequency electromagnet wave. After the high-frequency electromagnet wave is refracted by the ionosphere and is reflected by the sea surface, a sky wave signal is formed. An attitude measurement subsystem measures and acquires attitude data of the buoy platform in real time. A ground wave radar subsystem receives a ground wave signal by using the ground wave radar, and processes the signal to form a ground wave doppler spectrum. Simultaneously, the sky wave signal is received, ionosphere disturbance compensation is performed on the sky wave signal in a frequency domain and then the sky wave signal is processed to form a sky wave doppler spectrum. The ground wave radar subsystem reconstructs an actual geographic coordinate system according to the attitude data measured by the attitude measurement subsystem and then the ground wave or the sky wave doppler spectrum is used to inverse wind wave current data in the reconstructed actual geographic coordinate system. The sky wave emission subsystem and the ground wave radar subsystem carry out time synchronization by means of a GPS synchronization networking. The system can detect a sea region of any distance and is suitable for high sea detection.