A computer-implemented method executed by one or more satellites for assessing crop development by using synthetic aperture radar (SAR) is presented. The method includes generating SAR images from scanning fields including crops, monitoring grown of the crops within the fields during a predetermined time period, and estimating a height of the crops during the predetermined time period by using interferometric information from one or more of the SAR images and tracking change in height and growth rates. The method further includes differentiating between crops in different fields by monitoring changes in the height of the crops during an entire growing season.

A computer-implemented method executed by one or more satellites for assessing crop development by using synthetic aperture radar (SAR) is presented. The method includes generating SAR images from scanning fields including crops, monitoring grown of the crops within the fields during a predetermined time period, and estimating a height of the crops during the predetermined time period by using interferometric information from one or more of the SAR images and tracking change in height and growth rates. The method further includes differentiating between crops in different fields by monitoring changes in the height of the crops during an entire growing season.

A side-looking High Resolution Wide Swath Synthetic Aperture Radar, HRWS-SAR, system comprising an antenna array and a beamforming network. The antenna array comprises a plurality of antenna elements to transmit and receive electromagnetic waves. The beamforming network includes a plurality of true time delay lines, TTDLs connected to a plurality of phase shifters. Each phase shifter is connected to a respective one of the plurality of antenna elements. The beamforming network engages with the transmit antenna array to transmit the electromagnetic waves by performing beamsteering across a swath using a pulse. The pulse has a chirped waveform and a transmit pulse duration. Beamsteering is performed based on an increasing or decreasing frequency of the chirped waveform over the transmit pulse duration. The beamforming network engages with the antenna array to receive, during a receive time window, echoes corresponding to the electromagnetic waves reflected by or from the swath.

A synthetic aperture radar (SAR) system and method of operation advantageously implements dynamic self-cueing or autonomous cueing of successive high-resolution SAR data collection based on previously collected wide-swath SAR data, for instance without the intervention of ground-based resources. For example, target detection may be performed on-board a spaceborne or airborne SAR platform using wide-swath SAR data acquired via a first beam at a first frequency band, the first beam pointed at a first angle relative to an along-track direction. Subsequent activities are cued by the platform based on the previously collected wide-swath SAR data. For instance, the SAR platform may cue subsequent acquisition of SAR data via a second beam at a second frequency band, the second beam pointed at a second angle relative to an along-track direction. The SAR platform may advantageously employ a multi-band SAR antenna.

A Spotlight SAR imaging mode is implemented by a synthetic aperture radar (SAR) system in which an SAR controller intentionally spoils a transmit beam of the SAR antenna to form a spoiled transmit beam. The SAR system transmits pulses using the spoiled transmit beam, divides the SAR antenna into a plurality of azimuth apertures, receives received pulses by the SAR antenna using a number M of multiple receive beams, processes data received by each of the number M of multiple receive beams to generate a number M of sub-images by the SAR processor; and coherently combines two or more of the number M of sub-images to form a Spotlight image. Thus, a multi-aperture antenna comprises multiple azimuth apertures (i.e., a sub apertures), each formed from one or more azimuth phase centers. The sub-apertures can be independent from one another. The sub-apertures can keep a target illuminated by the beam for a longer time than conventional Stripmap mode, for example. The sub-apertures can be combined in processing to form a high resolution image, with high image quality.

A system for determining a location in a disadvantaged signal environment includes three aerial vehicles hovering at high altitude and spaced apart to form a triangle, and a mother aerial vehicle positioned a distance away and at a lower altitude. The mother aerial vehicle acquires and transmits coarse geolocation information, using a pulse compression, high-power X Band radar and directional antenna, to each of the three aerial vehicles to direct them to coarse geo-positions above designated respective ground locations. One of the three aerial vehicles has a synthetic aperture radar for producing a terrain strip-map that is mensurated against a map database to provide fine position adjustments for each of the three aerial vehicles, which are also also configured to transmit a respective signal coded with its latitude, longitude, and altitude, for a computing device to perform time difference of arrival measurements of the signals to determine its location.

Synthetic aperture radar (SAR) imaging systems that transmit repeated waveforms based upon pseudonoise sequences to generate SAR imaging data in accordance with various embodiments of the invention are disclosed. A synthetic aperture radar in accordance with one embodiment of the invention includes: a transmitter configured to transmit superchirps, where the superchirp is generated by convolving a kernel with a pseudonoise modulated impulse sequence having a flat power spectrum; a receiver configured to receive backscatters of transmitted superchirps and digitize the received backscatters; and signal processing circuitry configured to perform matched filtering on digitized backscatters.

A method and a system for detection and synthetic aperture (SA) imaging of a target are disclosed. The method may include illuminating a scene with a search signal transmitted from a moving platform, receiving a search return signal from a target present in the scene, and estimating, from the search return signal, the range and the angular location of the target. The method may also include generating an SA transmission signal and a local oscillator (LO) signal with a time delay therebetween based on the estimated range, and illuminating the scene with the SA transmission signal pointed along an imaging direction based on the estimated angular location of the target. The method may further include receiving an SA return signal from the target, mixing the SA return signal with the LO signal to generate SA signal data, and generating an SA image of the target from the SA signal data.

Multiple synthetic aperture radar SAR images of a target area on the earth are acquired using a satellite travelling in an orbit above the earth in a single pass of the satellite over the target area. In some methods, the data for each image is acquired from a different angle of incidence with respect to the target area. Then, the variation of quantity of backscattered radiation with respect to angle of incidence is analysed and used to identify matter imaged in a pixel or pixel group. In other methods, the data for each image is acquired from a different angle of incidence with respect to the target area, and the different angles of incidence are determined based on the specular reflection curve for a particular material. Then the quantity of backscattered radiation is analysed to determine whether the particular material is present based on the quantity of backscattered radiation. Extended dwell spotlight acquisition geometry may be used in which image data acquisition apparatus may be locked to illuminate same target as the satellite passes over the target for a period of for example 20 seconds.

The present disclosure provides a method for surface wear inspection using millimeter wave radar. The system initially receives a plurality of uncompressed raw Synthetic Aperture Radar (SAR) images. Further, a plurality of reconstructed SAR images are generated based on the plurality of uncompressed raw SAR images using a variable focusing based Range Doppler Algorithm (RDA). Further, a master image and a slave image are selected from the reconstructed SAR images and corresponding anchor points are assigned. Further a plurality of fine level and coarse level shift coordinates are computed based on the corresponding anchor points. Further, a net shift value is computed based on the plurality of fine level and coarse level shift coordinates. The master and the slave images are aligned based on the net shift value and the interferogram is generated. The interferogram is further analyzed to profile the corresponding deformation pertaining to the surface under test.