Microwave and millimeter wave imaging. An antenna array in communication with a signal source comprises a plurality of antennas by which a signal generated by the signal source is transmitted incident to an object located remotely from the antenna array and by which a signal reflected from the object is received by the antenna array. The signals transmitted by the antennas collectively have an effective electric field resembling a plane-wave within a target region in front of the antenna array. A plurality of detectors each connected to one of the antennas is configured to simultaneously receive the reflected signal and provide an output signal representative thereof. An image processor configured to execute an imaging algorithm generates a multi-dimensional profile representative of the object based on the output signals from the detectors.

Subsurface imaging with information of shape, volume, and dielectric properties is achieved with low frequencies and a ramp waveform. The low frequencies have a lower attenuation compared to the penetration losses of radar frequencies. The technique operates at wavelengths which are comparable to the object or void being imaged, and can be applied to detect and image underground aquifers, magma chambers, man-made tunnels and other underground structures.

Synthetic aperture radar transmit and receive antenna systems and methods of transmitting and receiving radar signals are disclosed. In one embodiment, a transmit and receive antenna system includes a transmit antenna array configured to transmit a plurality of radio frequency transmit signals, the transmit antenna array including a plurality of patch antenna elements mounted to a printed circuit board, each patch antenna element belonging to a subarray, and one or more power amplifiers, each power amplifier feeding a subarray of the patch antenna elements, and a reflectarray receive antenna configured to receive radio frequency signals including a plurality of reflectarray antenna elements mounted to a printed circuit board, at least one antenna feed configured to receive radio frequency signals reflected from the plurality of reflectarray antenna elements, and at least one low noise amplifier electrically connected to the at least one antenna feed.

Disclosed is a radar signal processing device 2 including frequency domain converters 201-1 to 201-M to convert raw data 11-1 to 11-M showing observation results acquired by a radar device 1 into those in a frequency domain, a signal restorer 202 to synthesize the raw data 11-1 to 11-M whose domain is converted into the frequency domain according to a least square method, a time domain converter 203 to return a signal series after synthesis to that in a time domain, and an image reproducer 204 to acquire a reproduced image 12 by performing image reproduction on the signal series whose domain is returned to the time domain.

A sensing system for a vehicle includes at least one radar sensor disposed at the vehicle and having a field of sensing exterior of the vehicle. The at least one radar sensor includes multiple transmitting antennas and multiple receiving antennas. The transmitting antennas transmit signals and the receiving antennas receive the signals reflected off objects. Multiple scans of radar data sensed by the at least one radar sensor are received at a control, and a vehicle motion estimation is received at the control. The control, responsive to received scans of sensed radar data, detects the presence of one or more objects exterior the vehicle and within the field of sensing of the at least one radar sensor. The control, responsive to the received scans of sensed radar data and the received vehicle motion estimation, matches objects detected in the scans and determines angles toward the detected objects.

In a method and device for suppressing range ambiguity in Synthetic Aperture Radar (SAR), azimuth transmission-phase modulation is performed respectively, using a preset rule for phase modulation, on pulse signal data transmitted on a channel of Horizontal (H) polarization and pulse signal data transmitted on a channel of Vertical (V) polarization. Full polarimetric echo data corresponding to the transmission-phase modulated pulse signal data transmitted on the channel of H polarization and the transmission-phase modulated pulse signal data transmitted on the channel of V polarization are acquired. Azimuth phase demodulation is performed on the full polarimetric echo data using a preset rule for phase demodulation. Echo data are acquired by filtering out, using a preset azimuth filter, range-ambiguity energy from the phase demodulated full polarimetric echo data.

A radar assembly for receiving signals at spaced frequencies from an unknown transmitting source comprising a receiver operative to receive signals; the receiver comprising a series of channels, each channel comprising a low pass filter configured to allow passage of a signal from an unknown transmitting source, an analog to digital converter configured to transform the signal from the unknown transmitting source to a digital signal, a Hilbert transform configured to transform the digital signal from the unknown transmitting source into a single sideband signal, a Fourier transform configured to transform the single sideband signal into a plurality of regularly spaced frequency samples, and an inverse Fourier transform for extracting regularly spaced frequency samples; whereby extracted pulses form a train of pulses that are inputted into an imager which utilizes synthetic aperture radar to form an image of the area of interest containing the unknown transmitting device and method thereof.

This invention provides millimeter wave holographic 3D imaging detection system, which comprises: a transmitting antenna configured to transmit a millimeter wave transmitting signal to an object to be detected; a receiving antenna configured to receive an echo signal from the object to be detected; a millimeter wave transceiving module configured to generate the millimeter wave transmitting signal transmitted to the object to be detected and receive and process the echo signal from the receiving antenna; a scanning device configured to support the millimeter wave transceiving module, the transmitting antenna and the receiving antenna, and move the millimeter transceiving module, the transmitting antenna and the receiving antenna along a preset track, so as to scan the object to be detected with millimeter waves; a data gathering and processing module configured to gather and process the echo signal output from the millimeter wave transceiving module to generate a 3D image of the object to be detected; and an image display unit configured to display the 3D image generated by the data gathering and processing module. Besides, this invention also provides a method of millimeter wave holographic 3D imaging detection on an object to be detected using the above system thereof. The technical solution of this invention has the advantages of simple structure, high resolution, short imaging time, and larger field of view.

Disclosed is a calibration method of performing dual radiometric compensation by using an antenna gain pattern of a synthetic aperture radar (SAR) both in a time domain and in a frequency domain. The method may include performing frequency-domain radiometric compensation in relation to an elevation angle and performing time-domain radiometric compensation in relation to a frequency to calibrate the antenna gain pattern.

The present disclosure relates to a method for computer-implemented processing of SAR raw data, which comprises radar echoes from radar pulse. An interference radar echo and an interference pulse are associated with a respective radar pulse, wherein the interference pulse and the respective radar pulse have orthogonal waveforms. SAR raw data are focused by a first focusing on the interference pulses including a range compression and an azimuth compression, to obtain first focused data, where a filtering is used for the range compression of a respective radar pulse, which filtering is matched to the waveform of the associated interference pulse. Thereafter, the first focused data undergo a signal suppression, which at least partially suppresses the interference radar echo, as a result of which second focused data are obtained. These second focused data finally undergo a defocusing including range decompression and azimuth decompression to obtain modified SAR raw data.