Concept Development for Advanced Spaceborne Synthetic Aperture Radar

electrical and electronics
Concept Development for Advanced Spaceborne Synthetic Aperture Radar (GSC-TOPS-323)
Advanced spaceborne radar system for the measurement of terrestrial biomass and ecosystem structure
Overview
Spaceborne Synthetic Aperture Radar (SAR) can globally monitor dynamic processes on the Earths Surface. The last SAR to be developed and deployed by NASA was in the year 2000. This systems high costs inhibited development of new and improved designs. NASA has developed a new, state of the art, SAR system that is capable of providing capabilities beyond established systems and at a fraction of the cost.

The Technology
The current innovation utilizes heritage flight proven L-band Digital Beamforming Synthetic Aperture Radar (DBSAR) in conjunction with a new P-Band Digital beamforming Polarimetric and Interferometric EcoSAR (ESTO IIP) architecture. The system employs digital beamforming (DBF) and reconfigurable hardware to provide advanced radar capabilities not possible with conventional radar instruments. The SAR is operated without the use of a slewing antenna allowing the single radar system to provide polarimetric imaging, interferometry, and altimetry or scatterometry data types. The SAR is also capable of Sweep-SAR, simultaneous SAR/GNSS-R , and simultaneous active/passive techniques. This system has an increased coverage area and can rapidly image large areas of the surface using the simultaneous left/right imaging. The resulting images maintain their full resolution and allows for faster full coverage mapping
Benefits
  • Rapidly image large areas of the surface
  • Single radar system can provide different data types
  • Multiple synthetic aperture radar (SAR) imaging techniques

Applications
  • Remote Sensing
  • Environmental Modeling
Technology Details

electrical and electronics
GSC-TOPS-323
GSC-17016-1
10649081
Similar Results
Digital Beamforming Interferometry
Digital Beamforming Interferometry
NASA Goddard Space Flight Center (GSFC) has developed a new approach that uses a single phased array antenna and a single pass configuration to generate interferograms, known as Digital Beamforming Interferometry. A digital beamforming radar system allows the implementation of non-conventional radar techniques, known as Digital Beamforming Synthetic Aperture Radar Multi-mode Operation (DBSAR). DBSAR is an L-Band airborne radar that combines advanced radar technology with the ability to implement multimode remote sensing techniques, including several variations of SAR, scatterometry over multiple beams, and an altimeter mode. The Multiple channel data acquired with a digital beamformer systems allows the synthesis of beams over separate areas of the antenna, effectively dividing the single antenna into two antennas. The InSAR technique is then achieved by generating interferograms from images collected with each of the antennas. Since the technique is performed on the data, it allows for synthesizing beams in different directions (or look angles) and performs interferometry over large areas. Digital Beamforming Interferometry has potential in many areas of radar applications. For example, NASA GSFC innovators developed the first P-Band Digital Beamforming Polarimetric Interferometric SAR Instrument to measure ecosystem structure, biomass, and surface water.
Rendition of NASA's FASTSAT in orbit.
High-Speed, Low-Cost Telemetry Access from Space
NASA's SDR uses Field-Programmable Gate Array (FPGA) technology to enable flexible performance on orbit. A first-generation FM-modulated transceiver is capable of operating at up to 1 Mbps downlink and 50 kbps uplink, full duplex. An FPGA performs Reed-Solomon (255,223) encoding, decoding, and bit synchronization, providing Consultative Committee for Space Data Systems (CCSDS) and Near Earth Network (NEN) telemetry protocol compatibility. The transceiver accepts data from the onboard flight computer via a source synchronous RS422 interface. NASA's second-generation full duplex SDR, known as PULSAR (programmable ultra-lightweight system-adaptable radio, Figures 1 and 2 below) incorporates command receiver and telemetry transmitters, as well as updated processing and power capabilities. An S-band command receiver offers a max uplink data rate of 300 Kbps and built-in QPSK demodulation. X- and S-Band telemetry transmitters offer a max downlink data rate of 150 Mbps and flexible forward-error correction (FEC) using Reed-Solomon encoding (LDPC rate 7/8 and 1/2 convolution in development), and it uses QPSK modulation. The use of FEC adds an order of magnitude increase in telemetry throughput due to an improved coding gain. An onboard FPGA uses high-speed logic for uplink/downlink and encoding/decoding processes. Balloon flight testing has been conducted and is ongoing for PULSAR.
Hurricane Dorian Seen From Aboard the Space Station. Former Goddard electrical engineer and current NASA astronaut Christina Koch snapped this image of Hurricane Dorian from the International Space Station during a flyover on Monday, September 2, 2019. The station orbits more than 200 miles above the Earth.
Direction of Arrival Estimation Signal of Opportunity Receiver
The Direction of Arrival Estimation Signal of Opportunity Receiver is a transceiver technology for small satellite and CubeSat platforms that enables maximization of antenna gain in a specific direction to receive desired signals and suppress signals from other directions. The receive is a four-channel transceiver system to be operating in a LEO orbit for receiving direct as well as reflected signal (signals reflected from the ground) of a communication satellite. An adaptive array processing is implemented to steer the receiver beam towards the GEO satellites as well as steer the antenna beam towards the ground. When the beam is steered towards the ground the receiver provides attenuation for the direct signal incident from the GEO satellite, thus isolating the reflected signal from the strong direct signal. Usually a simple pair of cross dipoles are used for receiving signals transmitted by communication satellites. One pair is used to receive direct signals and another pair is used receive reflected signals. These dipoles are ideally supposed to receive only the reflected signals from the ground. However, because of close proximity and strong coupling to each other through their mutual coupling and because of their broad beam patterns, these dipole antennas receive signals reflected from other targets, as well as the direct transmitted signal. Since the strength of direct signals will be above the strength of reflected signals, reflected signals typically are completely masked by the strong direct signals. The Direction of Arrival Estimation Signal of Opportunity Receiver maximizes antenna gain in a desired direction to maximize desired signal and suppress unwanted signals.
Low Frequency Portable Acoustic Measurement System
Low Frequency Portable Acoustic Measurement System
Langley has developed various technologies to enable the portable detection system, including: - 3-inch electret condenser microphone - unprecedented sensitivity of -45 dB/Hz - compact nonporous windscreen - suitable for replacing spatially demanding soaker hoses in current use - infrasonic calibrator for field use - piston phone with a test signal of 110 dB at 14Hz. - laboratory calibration apparatus - to very low frequencies - vacuum isolation vessel - sufficiently anechoic to permit measurement of background noise in microphones at frequencies down to a few Hz - mobile source for reference - a Helmholtz resonator that provides pure tone at 19 Hz The NASA system uses a three-element array in the field to locate sources of infrasound and their direction. This information has been correlated with PIREPs available in real time via the Internet, with 10 examples of good correlation.
satellite
Method and Associated Apparatus for Capturing, Servicing, and De-Orbiting Earth Satellites Using Robotics
This method begins with the optical seeking and ranging of a target satellite using LiDAR. Upon approach, the tumble rate of the target satellite is measured and matched by the approaching spacecraft. As rendezvous occurs the spacecraft deploys a robotic grappling arm or berthing pins to provide a secure attachment to the satellite. A series of robotic arms perform servicing autonomously, either executing a pre-programmed sequence of instructions or a sequence generated by Artificial Intelligence (AI) logic onboard the robot. Should it become necessary or desirable, a remote operator maintains the ability to abort an instruction or utilize a built-in override to teleoperate the robot.
Stay up to date, follow NASA's Technology Transfer Program on:
facebook twitter linkedin youtube
Facebook Logo Twitter Logo Linkedin Logo Youtube Logo