Spaceborne synthetic aperture radar system and method

A method of utilizing a synthetic aperture radar (SAR) apparatus comprising:

• providing a plurality of instrument panels containing a plurality of panel Radar Digital Units (RDUs), each of said instrument panels including a plurality of subarrays containing a plurality of subarray RDUs;
• wherein each of said plurality of panel RDUs and said plurality of subarray RDUs are configured to form transmit and receive beams, and to perform waveform generation, data acquisition, and onboard beamforming;
• connecting a plurality of feed network modules to said plurality of subarrays;
• providing a plurality of digital and radio frequency (RF) transceiver modules disposed on each of said instrument panels and connected to said plurality of feed network modules, said RF transceiver modules which enable transmit and receive signal conditioning;
• and
• connecting a plurality of antenna elements to said plurality of transceiver modules for signal transmission and reception;
• wherein said plurality of transceiver modules are used for both horizontal and vertical polarization channels, and interface both said plurality of subarrays and said plurality of antenna elements;
• said plurality of panel RDUs, said plurality of subarray RDUs, said plurality of transceiver modules, and said plurality of antenna elements, are arranged as subarrays of said plurality of instrument panels, said plurality of subarray RDUs comprising field programmable gate arrays (FPGAs) in printed circuit boards (PCB), wherein said plurality of transceiver modules are based on PCB designs or Monolithic Microwave Integrated Circuit (MMIC) technology, the method further comprising:
• transmitting beamforming with predetermined beam characteristics using software-defined waveforms at each of said plurality of subarrays;
• digitizing and processing each said receive channel of said plurality of transceiver modules to digitally beamform said beams with predetermined characteristics in a receive operation, wherein said plurality of subarrays maintain signal coherence among multiple elements in both digital and RF domains, and enable centralized waveform generation and data acquisition, further comprising:
• providing a timing control system;
• providing a plurality of FPGA data processors and waveform generators which enable said centralized waveform generation and data acquisition, as part of said FGPAs of said plurality of subarray RDUs, the method further comprising:
• creating a trigger signal using each of said waveform generators residing at each of said plurality of FGPAs of said plurality of subarray RDUs;
• and
• distributing said trigger signal to each of said plurality of subarrays, and synchronizing said plurality of subarrays by a radar pulse repetition frequency (PRF), such that said plurality of subarrays digitize and process radar signals, to remove timing disturbances and ambiguities caused by noise and part tolerances, wherein said plurality of antenna elements are a plurality of identical wideband and high polarization antenna elements, wherein said plurality of antenna elements include 50 antenna elements per each of said plurality of instrument panels, formed of 10 subarrays of five antenna elements each, wherein each of said plurality of antenna elements includes a dual polarized, aperture-coupled stacked patch antenna, comprising shells of aluminum walls around each of said plurality of antenna elements, with stacked resonating disks, and coupled to a plurality of feedline strips.