A method and system are presented for the formation of a constellation of small satellites (smallsats) for radar surveillance employing multiple input, multiple output (MIMO) radar operation. Such a constellation can be used for cost-effective fine angular resolution and persistent remote sensing of targets or regions above, below, or upon a planet's surface. Applications include, but are not limited to, surface mapping (including change detection), mapping of meteorological conditions, and monitoring of time-varying events. The method and system pertain to satellite configurations whose costs and aggregate masses are much less than those of traditional space-based radar measurements attempting to attain comparable angular resolution, while also providing intervals of persistent surveillance.

Airborne systems and methods for the detection, location and obtaining of images of buried objects and for the characterization of the composition of the subsoil. The systems comprise at least one aerial module with a radar unit that emits and/or captures radar signals and a positioning and guidance system with an accuracy equal to or less than 3 cm, and a ground station with a flight control system and a radar signal processing unit where radar signal processing algorithms are applied. The invention also comprises a method for the detection, localization and obtaining of images of buried objects and a method for the characterization of the composition of the subsoil. Applicable in sectors where it is necessary to perform the detection of buried objects, as for example in civil applications (detection of antipersonnel mines), pipeline inspection or in archaeology.

Embodiments of the invention are directed to a method of determining underground liquid content (e.g., water, sewage, etc.). Embodiments may include: receiving, from a radiofrequency radiation sensor, a main scan of an area, the main scan may include reflections from the area at RF range, and receiving typical roughness values of one or more types of water sources. Embodiments may further include: filtering from the main scan undesired water source types according to their typical roughness values, identifying a desired type of water source in the filtered main scan and receiving from the RF radiation sensor a set of scans of the area, each scan of the area includes reflections in the RF range taken prior to the receiving of the main scan. Embodiments may include calculating the underground water content at locations in the area based on the identified first type of water source and the received set of scans.

A method for detecting a horizontally buried linear object is provided, the horizontally buried linear object having a longitudinal extension. The method comprises moving, with a flying platform comprising a radar for synthetic aperture radar, SAR, vertical imaging, along a trajectory corresponding to a synthetic aperture. The method further comprises transmitting and receiving radar signals while moving along the trajectory corresponding to the synthetic aperture. The method also comprises forming a SAR image based on collected data representing radar signal reflections received from the ground. The method additionally comprises detecting one or more features in the formed SAR image relating to the horizontally buried linear object. Said trajectory is oriented in a direction substantially perpendicular to an expected orientation of the longitudinal extension of the horizontally buried object and traversing the horizontally buried object.

A digital beamforming synthetic aperture radar (SAR) mixes a first analog signal to generate a frequency-shifted first signal having a first spectral band, mixes a second analog signal to generate a frequency-shifted second signal having a second spectral band, positioned at a defined frequency offset from the first spectral band, and positioned non-overlapping relation with the first spectral band, combines the first and second frequency-shifted signals to generate a combined analog receive signal, and band-pass samples the combined analog receive signal to generate a digital baseband signal representative of the first and second analog signals. The SAR may mix the second analog signal to position the second spectral band in the Nyquist bandwidth, and in non-overlapping relationship with the first spectral band. Mixing may include down converting the analog signal.

A subsurface interferometric synthetic aperture radar (InSAR) imaging technique for the detection and localization of underground targets in the presence of a rough ground surface comprises a two-step procedure. First, surface clutter suppression is performed with a polarimetric difference operation that does not alter the propagation phase of the target scattered signal; then a subsurface interferometric algorithm is applied to infer target depth by correlating the clutter-suppressed images obtained along two observation paths.

The present invention relates to a method and an apparatus for continuously detecting a hazardous and noxious substance from multiple satellites, and specifically, provides a method and an apparatus for continuously detecting a hazardous and noxious substance from multiple satellites, the method and apparatus: receiving a multi-satellite image which is photographed by a multi-satellite comprising a satellite having an imaging radar (SAR), a satellite having an infrared sensor, and a satellite having an electronic optical sensor; acquiring a reference image, of the satellite having the SAR, including a ground control point of an observed region; extracting a corresponding point between the reference image and the multi-satellite image; implementing the image matching and geometric correction for the multi-satellite image by using the extracted corresponding point; confirming at least one among the brightness value of pixels of the SAR satellite image, the temperature value of pixels of the infrared satellite image or the color value of pixels of the optical satellite image which are included in the corrected multi-satellite image so as to detect the hazardous and noxious substance, and determine the flow information, thereby detecting continuously and stably the hazardous and noxious substance.

A radar antenna for a flight vehicle that follows a flight path comprises a radio frequency (RF) reflector, and separated first arrays of first RF feed elements to form, with the reflector, respective first fixed radar beams that are directed at the Earth and positionally offset with respect to each other, such that when the radar antenna follows the flight path, the respective first fixed radar beams trace respective first subswaths on the Earth that are separated from each other by respective subswath gaps.

Method and device for radar transmission and reception by dynamic change of polarization notably for the implementation of interleaved radar modes are provided. A radar transmission-reception method and a device for implementing this method, the method alternatively implementing two modes of operation, a short range mode exploiting short pulses and a long range mode exploiting modulated long pulses, the method consisting, for each mode, in: producing two synchronous radiofrequency (RF) transmission signals having between them a phase-shift of controllable given value; radiating two radiofrequency waves, each corresponding to one of the transmission RF signals produced, by means of two colocated radiating sources each having a given polarization axis; handling the reception of the backscattered radiofrequency signals picked up by each of the radiating sources, and delivering two radiofrequency (RF) reception signals each corresponding to a radiofrequency signal picked up by one of the radiating sources, a phase-shift being applied between the two signals delivered, being able to be determined as being equal to .

Embodiments of the invention are directed to a method of determining underground liquid (e.g., water) content. Embodiments of the method may include: receiving a scan of an area at a first polarization, the scan scans including reflections from the area. Embodiments of the invention may include receiving an additional data. Embodiments of the method may further include filtering electromagnetic noise from the scan using the additional data. Embodiments of the method may further include creating a water roughness map based on typical roughness values of various types of water sources and the filtered scan, identifying a first type of water sources using the water roughness map and the filtered scan and calculating the water content at locations in the area based on the identified first type of water sources.