NISAR Model-Based Radar Antenna Pointing, Antenna Pattern and System Performance Evaluation
UNKNOWN
Niamsuwan, Noppasin↗
Engineering topics
Ghaemi, Hirad
Publications and source records attributed to Ghaemi, Hirad.
Advances in Digital Calibration Techniques Enabling Real-Time Beamforming SweepSAR Architectures
Real-time digital beamforming, combined with lightweight, large aperture reflectors, enable SweepSAR architectures, which promise significant increases in instrument capability for solid earth and biomass remote sensing. These new instrument concepts require new methods for calibrating the multiple channels, which are combined on-board, in real-time. The benefit of this effort is that it enables a new class of lightweight radar architecture, Digital Beamforming with SweepSAR, providing significantly larger swath coverage than conventional SAR architectures for reduced mass and cost. This paper will review the on-going development of the digital calibration architecture for digital beamforming radar instrument, such as the proposed Earth Radar Mission's DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice) instrument. This proposed instrument's baseline design employs SweepSAR digital beamforming and requires digital calibration. We will review the overall concepts and status of the system architecture, algorithm development, and the digital calibration testbed currently being developed. We will present results from a preliminary hardware demonstration. We will also discuss the challenges and opportunities specific to this novel architecture.
TR (Transmit/Receive)↗
RFI-SIM: RFI Simulation Package
RFI-SIM simulates the RFI environment to estimate the interference from terrestrial emitters into spacecraft, or vice versa. A high-fidelity simulation of the RFI environment has been developed by employing all antenna- related and radar system-related parameters of multiple emitters, as well as that of the desired spacecraft. In the simulation, the real-time analysis of the interference and its effects on error budgets of a desired radar system is taken into account. This provides a reliable tool for radar system design to deal with RFI issues and to evaluate the sensitivity of various parts of a radar system including antenna pattern, RF front-end and digital processing to RFI signals.
Ghaemi, Hirad↗
Advances in Digital Calibration Techniques Enabling Real-Time Beamforming SweepSAR Architectures
No abstract available
TR (Transmit/Receive)↗
Ka-band Digitally Beamformed Airborne Radar Using SweepSAR Technique
A paper describes a frequency-scaled SweepSAR demonstration that operates at Ka-Band (35.6 GHz), and closely approximates the DESDynl mission antenna geometry, scaled by 28. The concept relies on the SweepSAR measurement technique. An array of digital receivers captures waveforms from a multiplicity of elements. These are combined using digital beamforming in elevation and SAR processing to produce imagery. Ka-band (35.6 GHz) airborne SweepSAR using array-fed reflector and digital beamforming features eight simultaneous receive beams generated by a 40-cm offset-fed reflector and eight-element active array feed, and eight digital receiver channels with all raw data recorded and later used for beamforming. Illumination of the swath is accomplished using a slotted-waveguide antenna radiating 250 W peak power. This experiment has been used to demonstrate digital beamforming SweepSAR systems.
Sadowy, Gregory A.↗
First Results from an Airborne Ka-band SAR Using SweepSAR and Digital Beamforming
NASA/JPL has developed SweepSAR technique that breaks typical Synthetic Aperture Radar (SAR) trade space using time-dependent multi-beam DBF on receive. Developing SweepSAR implementation using array-fed reflector for proposed DESDynI Earth Radar Mission concept. Performed first-of-a-kind airborne demonstration of the SweepSAR concept at Ka-band (35.6 GHz). Validated calibration and antenna pattern data sufficient for beam forming in elevation. (1) Provides validation evidence that the proposed Deformation Ecosystem Structure Dynamics of Ice (DESDynI) SAR architecture is sound. (2) Functions well even with large variations in receiver gain / phase. Future plans include using prototype DESDynI SAR digital flight hardware to do the beam forming in real-time onboard the aircraft.
Digital Beamforming↗
First Results from an Airborne Ka-Band SAR Using SweepSAR and Digital Beamforming
SweepSAR is a wide-swath synthetic aperture radar technique that is being studied for application on the future Earth science radar missions. This paper describes the design of an airborne radar demonstration that simulates an 11-m L-band (1.2-1.3 GHz) reflector geometry at Ka-band (35.6 GHz) using a 40-cm reflector. The Ka-band SweepSAR Demonstration system was flown on the NASA DC-8 airborne laboratory and used to study engineering performance trades and array calibration for SweepSAR configurations. We present an instrument and experiment overview, instrument calibration and first results.
instrument calibration↗
A Spaceborne Design and Airborne Demonstration of Digitally-Beamformed Antennas for SweepSAR Imaging
No abstract available
Deformation Ecosystem??Structure Dynamics of Ice (↗
The DESDynI Synthetic Aperture Radar Array-Fed Reflector Antenna
DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a largeaperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit/ receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called 'SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.
Chamberlain, Neil↗
Ka-Band Digital Beamforming and SweepSAR Demonstration for Ice and Solid Earth Topography
GLISTIN is an instrument concept for a single-pass interferometric SAR operating at 35.6 GHz. To achieve large swath widths using practical levels of transmitter power, a digitally-beamformed planar waveguide array is used. This paper describes results from a ground-based demonstration of a 16-receiver prototype. Furthermore, SweepSAR is emerging as promising technique for achieving very wide swaths for surface change detection. NASA and DLR are studying this approach for the DESDynI and Tandem-L missions. SweepSAR employs a reflector with a digitally-beamformed array feed. We will describe development of an airborne demonstration of SweepSAR using the GLISTIN receiver array and a reflector.
Sadowy, Gregory↗