The present invention relates to a method and system for Phaseless Passive Synthetic Aperture Radar (PPSAR) imaging. Existing method for image reconstruction requires large number of measurements for satisfactory PPSAR image reconstruction. However, this leads to provisioning of more on-board storage and/or a high-speed data link between a mobile platform and a ground station. These requirements are undesirable in practice as PPSAR image reconstruction systems are deployed on resource constrained platforms. The present disclosure uses a regularized Wirtinger Flow (rWF) based approach that uses appropriate regularizers to facilitate the PPSAR image reconstruction with fewer measurements. Further the PPSAR image reconstruction is achieved using Alternating Direction Method of Multipliers (ADMM) by employing standard denoisers such as Total Variation (TV), Block-matching and 3D filtering (BM3D) and, Deep Image Prior (DIP). Further the present disclosure considers an actual location of transmitter for PPSAR imaging that yields better image reconstruction.

A measurement apparatus of the present disclosure includes a measuring unit configured to acquire the reflected wave of a radio wave applied to a float and measure the state of a liquid based on the intensity of the acquired reflected wave. Then, the float is configured to float in a liquid in a manner such that a floating height relative to the liquid changes in accordance with the state of the liquid, and is further configured in a manner such that the intensity of the reflected wave of an applied radio wave changes in accordance with a change in the floating height relative to the liquid.

Some embodiments are directed to a radar imaging system that includes a radar transmitter configured to transmit radar at a target; an aperture including an array of physically independent airborne carriers, each of the carriers configured to receive radar echoes from the target; and a base station, which may be located at ground level, in communication with each of the airborne carriers to receive the radar echoes and determine an image of the target from the received radar echoes.

A point location method for a vehicle moving on a constrained trajectory, implemented by a location device comprises tachometry means, odometry means, a group of at least one satellite geopositioning receiver and a time base synchronized to a satellite geopositioning system, the location device detecting the passage of the vehicle closest to a predetermined position by exploiting knowledge of the displacement of the vehicle, by predicting the form of a set of satellite geopositioning signals at the predetermined position and by testing the match between the predicted signals and those received by the group of at least one satellite geopositioning receiver, the displacement of the vehicle being determined from data supplied by the odometry means and a mapping of the trajectory.

In some examples, a radar system comprises a plurality of antenna elements spatially distributed to form a sparse antenna array orthogonal to a range dimension of the radar imaging system, wherein the plurality of antenna elements are configured to transform a plurality of independent radar signals for a field of view. The system can also include an image processing system that is configured to recover interaction information gained from interaction of the plurality of independent radar signals with the field of view; use the interaction information to identify radar imaging data about the field of view; and form one or more three-dimensional (3D) voxels of the field of view using the radar imaging data.

Systems and methods are provided for synchronizing a bistatic inverse synthetic aperture radar (ISAR) imaging radar system using only the signal that travels directly between the transmitter and receiver. In an embodiment, an extracted direct path signal is used as a matched filter reference function. In an embodiment, full pulse compression is used for a matched filter implementation. Embodiments of the present disclosure provide systems and methods for detecting and extracting the direct path signal and using this direct path signal to synchronize the received signal stream in a bistatic ISAR system.

A phase synchronization method is provided. The phase synchronization method includes: a second Synthetic Aperture Radar (SAR) receives a first phase synchronization signal transmitted by a first SAR to obtain a first receipt signal; the first SAR receives a second phase synchronization signal transmitted by the second SAR to obtain a second receipt signal; a peak phase difference between a peak phase of the first receipt signal and a peak phase of the second receipt signal is determined, and a compensation phase is determined using a first preset rule according to the peak phase difference; and phase compensation is performed on an echo signal received by the second SAR according to the compensation phase, the echo signal is generated by the radar signal transmitted by the first SAR. A phase synchronization device, a storage medium and an information processing device are also provided.

Jammer location is based on detected powers received by at least one receiver of signals from the satellite navigation system on board a carrier, by estimation, for each satellite, of the power of the noise at the output of each receiver according to the bearing and distance with respect to the carrier, a calculation of the sum of estimated powers, and extraction of the local maxima in terms of bearing and distance by using a synthetic aperture antenna carrying out a coherent integration of received signals in the direction of each bearing angle by using the known movement of the carrier, in which estimation of the power of the noise at the output of each receiver uses a plurality of coherent integrators and non-coherent integrators, with durations matched to the transit time of a source in the beam of the antenna for various distances for the non-coherent integrators.

An observation system for observing a region of interest. The observation system has multiple mobile sensor carrier platforms and a resource allocation unit. The mobile sensor carrier platforms may be configured as satellites having a sensor signal emitter and/or a sensor signal receiver, for example. The resource allocation unit is configured to assign tasks to the sensor carrier platforms on the basis of various criteria in order to improve the efficiency for carrying out the tasks and the completion rate.

In some aspects, the disclosure is directed methods and systems for screening an unconstrained subject. A plurality of transmitters may be spatially distributed on two sides along a path of movement of a subject. Each of the transmitters may transmit, in sequence, radiation to be scattered from the subject. A plurality of sensors may be spatially distributed on the two sides and coherently configured with respect to the plurality of transmitters. The plurality of sensors may collect measurements of scattered radiation corresponding to the radiation transmitted by each of the plurality of transmitters. An imaging module may generate, based on the collected measurements, a two-dimensional or three-dimensional reconstruction estimate of body surface of the subject with one or more attached foreign objects.