The present invention relates to an advanced spaceborne Synthetic Aperture Radar (SAR) system and method that can provide high resolution measurements of the Earth or planetary surface, overcoming limitations in conventional SAR systems, and reduce development costs. The present invention utilizes advanced and innovative techniques, such as software defined waveforms, digital beamforming (DBF) and reconfigurable hardware, to provide radar capabilities not possible with conventional radar instruments, while reducing the radar development cost. The SAR system architecture employs a modular, low power, lightweight design approach to meet stringent spaceborne radar instrument requirements. Thus, the present invention can enable feasible Earth and planetary missions that address a vast number survey goals, including the measurement of ecosystem structure and extent, surface and sub-surface topography, subsurface stratigraphy, soil freeze-thaw, ice sheet composition and extent, glacier depth, and surface water, among many others.

Transmission antennas (2-#1 to 2-#M) transmit radiowaves of frequency bands uncorrelated with each other. Receivers (5-#1 to 5-#L) receives target-reflected waves reflected by a target. Pulse compressors (7-#1 to 7-#L) and transmission DBF units (8-#1 to 8-#L) suppress false peaks generated by the Doppler frequency in the target-reflected waves and combines the target-reflected waves. A reception DBF unit (9) and a target detector (10) detect the target based on the results of the combined signals.

A system and method are provided for processing echo signals reflected from one of more targets in a radar field-of-view. The method includes receiving echo signals reflected from one or more targets in the radar field-of-view in response to a sequence of transmit pulses; generating a received signal vector containing samples from the received echo signals; and applying the received signal vector to a set of filters configured to calculate a Doppler spectrum for a set of Doppler frequencies to which each filter is tuned, wherein an integration processing time for each filter varies relative to the Doppler frequency of each filter.

A system and method to resolve angle of arrival (AOA) ambiguity in a radar system include receiving received reflections at a plurality of transceiver nodes. Each transceiver node among the plurality of transceiver nodes of the radar system receives one or more of the received reflections at respective one or more receive elements. The method includes determining candidate AOAs {circumflex over (?)}.sub.i based on phases differences in the received reflections at the plurality of transceiver nodes, and determining Doppler frequencies f.sub.d.sup.i based on the received reflections. An estimated AOA {circumflex over (?)} is selected from among the candidate AOAs {circumflex over (?)}.sub.i based on matching metrics ?.sub.i between the Doppler frequencies and the candidate AOAs {circumflex over (?)}.sub.i.

A method for Doppler-enhanced radar tracking includes: receiving a reflected probe signal at a radar array; calculating a target range from the reflected probe signal; calculating a first target angle from the reflected probe signal; calculating a target composite angle from the reflected probe signal; and

calculating a three-dimensional position of the tracking target relative to the radar array from the target range, first target angle, and target composite angle.

Systems and methods for measuring velocity and acceleration with a radar altimeter. In certain embodiments, a method for measuring velocity magnitude of a platform in relation to a surface includes transmitting a radar beam, wherein the radar beam is aimed toward a surface. The method also includes receiving a plurality of reflected signals, wherein the plurality of reflected signals correspond to portions of the transmitted radar beam that are reflected by a plurality of portions of the surface. Further, the method includes applying Doppler filtering to the plurality of signals to form at least one Doppler beam. Also, the method includes identifying range measurements within each Doppler beam in the at least one Doppler beam. The method further includes calculating one or more coefficients of the Taylor expansion of the velocity magnitude based on the range measurements of the at least one Doppler beam.

Methods, apparatus, systems and articles of manufacture are disclosed for distributed, multi-node, low frequency radar systems for degraded visual environments. An example system includes a transmitter to transmit a radar signal. The example system includes a distributed network of radar receivers to receive the radar signal at each receiver. The example system includes a processor to determine a first range and a first angular position of a background point based on return time, wherein the first range and the first angular position are included in first data; determine a second range and a second angular position of the background point based on doppler shift, wherein the second range and the second angular position are included in second data; determine a refined range and a refined angular position, wherein the refined range and refined angular position are included in third data, and generate a radar map based on third data.

A new radar is disclosed possessing desirable attributes for close range, short event time, high data rate sensing and data collection applications. A Continuous Wave (CW) or very high Pulse Repetition Frequency (PRF) Pulse based waveform, nominally with very high duty cycle (i.e. highly range aliased), is amplified and transmitted from one antenna, and after reflection from targets of interest, is received by one or a plurality of receive antennas. Both transmit and receive are optimally synchronous and phase coherent. The received signals are down converted to baseband leaving only the Doppler frequency from the targets of interest. These Doppler frequencies change over Fast Time as a function of the specific target trajectory and speed. A bank of time dependent correlation filters, each tuned to a different trajectory hypothesis, are used to integrate up the Doppler Signal for targets traveling the hypothesized trajectory, and decorrelated those that are not.

An electronic device includes a transmission antenna, a reception antenna, and a signal processor. The transmission antenna transmits a transmission wave. The reception antenna receives a reflected wave that is the transmission wave having been reflected. The signal processor calculates a distance and a relative velocity between the electronic device and an object that reflects the transmission wave, based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave. The signal processor combines the distance and the relative velocity in accordance with a number of combinations set as a number of times the reception signal is combined.

An interferometric radar comprising an arm (2), which rotates with respect to an axis (z) of a plane (zx) orthogonal to an axis of rotation (y), a system of antennas (1), which are fixed to said arm (2), are able both to move along the arm and to describe complete revolutions along a circular path about said axis (y), and are oriented in a direction of sight (a) parallel to the axis (y), motor-drive means (3) for driving the arm (2) and the system of antennas along the arm, a data-acquisition and processing unit (10) operatively connected to said antenna (1) for acquiring a succession of images detected by the antenna during its revolution about the axis (y) and making differential interferometric calculations for measuring at least one component of the displacement of one or more targets in the field of view.