Dmitriy L. Bekker

The Geostationary Fourier Transform Spectrometer

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The GeoFTS instrument is a half meter cube size instrument designed to operate in geostationary orbit as a secondary “hosted” payload on a commercial geostationary satellite mission. The advantage of GEO is the ability to continuously stare at a region of the earth, enabling frequent sampling to capture the diurnal variability of biogenic fluxes and anthropogenic emissions from city to continental scales. The science goal is to obtain a process-based understanding of the carbon cycle from simultaneous high spatial resolution measurements of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) many times per day in the near infrared spectral region to capture their spatial and temporal variations on diurnal, synoptic, seasonal and interannual time scales. The GeoFTS instrument is based on a Michelson interferometer design with a number of advanced features incorporated. Two of the most important advanced features are the focal plane arrays and the optical path difference mechanism. A breadboard GeoFTS instrument has demonstrated functionality for simultaneous measurements in the visible and IR in the laboratory and subsequently in the field at the California Laboratory for Atmospheric Remote Sensing (CLARS) observatory on Mt. Wilson overlooking the Los Angeles basin. A GeoFTS engineering model instrument is being developed which will make simultaneous visible and IR measurements under space flight like environmental conditions (thermal-vacuum at 180 K). This will demonstrate critical instrument capabilities such as optical alignment stability, interferometer modulation efficiency, and high throughput FPA signal processing. This will reduce flight instrument development risk and show that the GeoFTS design is mature and flight ready.

The prototype development phase of the CubeSat On-board processing Validation Experiment

The Xilinx Virtex-5QV FPGA is a new radiation-hardened-by-design (RHBD) part that is targeted as the spaceborne processor for the Decadal Survey Aerosol-Cloud-Ecosystem (ACE) missions Multiangle SpectroPolarimetric Imager (MSPI) instrument12. A key technology development needed for MSPI is on-board processing (OBP) to calculate polarimetry data as imaged by each of the 9 cameras forming the instrument. With funding from NASAs ESTO3 AIST4 Program, JPL is demonstrating how signal data at 95 Mbytes/sec over 16 channels for each of the 9 multi-angle cameras can be reduced to 0.45 Mbytes/sec. This is done via a least-squares fitting algorithm implemented on the Virtex-5 FPGA operating in real-time on the raw video data stream [1]. Last year at this conference the results of a feasibility study between JPL and U. Michigan were presented in a paper titled, “A CubeSat Design to Validate the Virtex-5 FPGA for Spaceborne Image Processing.” Out of that study, a new task has been funded by NASAs ESTO ATI5 Program to integrate the MSPI OBP algorithm on the Virtex-5 FPGA as a payload to the University of Michigans M-Cubed CubeSat, manifest a launch opportunity, and gain on-orbit validation of this OBP platform to thereby advance the Technology Readiness Level (TRL) for MSPI and the ACE mission. This new task is called COVE (CubeSat On-board processing Validation Experiment) and is the topic of this paper. The COVE task is an 18-month effort to develop the flightready U. Michigan M-Cubed CubeSat with the integrated JPL OBP payload. The targeted completion date is September 2011. M-Cubeds primary payload is an OmniVision 2 MegaPixel CMOS camera that will take quality color images of the Earth from Low Earth Orbit (LEO) and save them to a Taskit Stamp9G20 microprocessor. This paper presents the prototype design and integration of the M-Cubed microprocessor system with the JPL payload that provides the image processing platform for on-orbit OBP validation. The high-level requirements and interface specifications for the delivery of the JPL FPGA-based payload hardware to the University of Michigan will be described. Finally, a recent decision regarding a launch opportunity for M-Cubed will be reported.

ISAAC - a case of highly-reusable, highly-capable computing and control platform for radar applications

ISAAC is a highly capable, highly reusable, modular, and integrated FPGA-based common instrument control and computing platform for a wide range of instrument needs as defined in the Earth Science National Research Council (NRC) Decadal Survey Report. This paper presents its motivation, technical approach, and the infrastructure elements. It also describes the first prototype, ISAAC I, and its application in the design of SMAP L-band radar digital filter.

Real-time data processing for an advanced imaging system using the Xilinx Virtex-5 FPGA

The multi-angle spectro-polarimetric imager (MSPI) is an advanced camera system under development at JPL for possible future consideration on a satellite based Aerosol-Cloud-Environment (ACE) mission as defined in the National Academies 2007 Decadal Survey. The MSPI project consists of three phases: Ground-MSPI, Air-MSPI, and Space-MSPI. Ground-MSPI is a ground-based demonstration focused on characterizing the imager optics and performance. Air-MSPI will be an updated version of the ground system to be flown on an ER-2 aircraft. Lessons learned from the ground- and air-based demonstrations will be used in the design of the final satellite-based Space-MSPI instrument. In order to capture polarimetric data, the data collection algorithm oversamples the desired spatial resolution by a large factor. The actual polarimetric information can be efficiently extracted from this oversampled data. It has been proposed to do this extraction on the spacecraft for the purposes of reducing the total downlink data rate. As described in [1], the processing can be done in non-realtime on a Xilinx Virtex-4 FPGA. We have shown that this processing can be done in real-time on a Xilinx Virtex-5 FXT FPGA. Pseudo-random data simulating Ground-MSPI data stream is processed on the FPGA and the resulting polarimetric parameters are output using an Ethernet link to a host PC for verification. This demonstration is a stepping stone to an effective implementation for the Space-MSPI instrument.

An FPGA-based Focal Plane Array interface for the Panchromatic Fourier Transform Spectrometer

Panchromatic Fourier Transform Spectrometer (PanFTS) is an Instrument Incubator Program (IIP) funded development to build and demonstrate a single instrument capable of meeting or exceeding the requirements of the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission. The PanFTS design provides atmospheric measurement capabilities in the IR and UV-Vis by using imaging FTS to provide full spatial coverage. For the atmospheric composition, the instrument includes up to four Focal Plane Arrays (FPA) of 256×256 pixels that are read at a frame rate of 8 kHz. We have developed an interface that records pixel data from commercially available IR FPAs that are capable of the required frame rate at a lower spatial coverage, and of the required spatial coverage at a lower frame rate. This interface uses high speed ADCs from Analog Devices and the Xilinx Virtex-5FXT FPGA (V5FXT). The IR signal chain electronics and the demonstration of the FPA data capture are highlighted in this paper. Achieving the full spatial coverage will require FPAs with in-pixel ADCs using delta-sigma conversion. JPL has developed a read-out integrated circuit (ROIC) utilizing this technique and has bump-bonded it to the detector portion of an FPA. The data acquisition and processing system for handling delta-sigma conversion from this new imager is the current work of the PanFTS IIP.

A CubeSat design to validate the Virtex-5 FPGA for spaceborne image processing

The Earth Sciences Decadal Survey identifies a multiangle, multispectral, high-accuracy polarization imager as one requirement for the Aerosol-Cloud-Ecosystem (ACE) mission. JPL has been developing a Multiangle SpectroPolarimetric Imager (MSPI) as a candidate to fill this need. A key technology development needed for MSPI is on-board signal processing to calculate polarimetry data as imaged by each of the 9 cameras forming the instrument. With funding from NASAs Advanced Information Systems Technology (AIST) Program, JPL is solving the real-time data processing requirements to demonstrate, for the first time, how signal data at 95 Mbytes/sec over 16-channels for each of the 9 multiangle cameras in the spaceborne instrument can be reduced on-board to 0.45 Mbytes/sec. This will produce the intensity and polarization data needed to characterize aerosol and cloud microphysical properties. Using the Xilinx Virtex-5 FPGA platform, a polarimetric processing least-squares fitting algorithm is under development to meet MSPIs on-board processing (OBP) requirements. The Virtex-5 FPGA is not yet space-flight qualified; however, an in-flight validation of this technology on a pre-cursor CubeSat mission is valuable toward advancing the technology readiness level for MSPI and the ACE mission. 1,2

Validation of real-time data processing for the Ground and Air-MSPI systems

JPL is currently developing the multi-angle spectro-polarimetric imager (MSPI), targeted for the Aerosol-Cloud-Ecosystems (ACE) mission, as defined in the National Academies 2007 Decadal Survey. In preparation for the space instrument, the MSPI team has built two incremental camera systems (Ground- and Air-MSPI) to improve understanding of the proposed architecture. Ground-MSPI is a gimballed instrument used primarily for stationary observation and characterization of the imager and optics. The ER-2 based Air-MSPI operates in a step-and-stare mode, providing multi-angle imaging of a static target. This mode-of-operation simulates the observation scenario of the space instrument. Physically, MSPI is a pushbroom camera with a specialized frontend. Before imaging, light entering the camera passes through a pair of photoelastic modulators and a set of pattern polarizers. These optical elements act on the light to make polarimetric extraction computationally feasible. Calculating polarimetric parameters from the imagers data stream requires a real-time least-squares computation that produces coefficients of a truncated time-series expansion of the image. As reported in [1][2], the data processing algorithm can operate in real-time on a Xilinx Virtex-5 FPGA. Moving beyond verification with an onboard data source, the algorithm has been validated on a commercial development board interfaced with the ground camera. In addition, the algorithm has been instantiated within the Air-MSPI electronics boards FPGA, and in situ first-light has been achieved.

An FPGA-based data acquisition and processing system for the MATMOS FTIR instrument

The MATMOS Fourier Transform Infrared (FTIR) spectrometer is a concept instrument designed to measure the Mars atmospheric composition using solar occultation from orbit. MATMOS requires high sampling rate (up to 300 kHz), high dynamic range (up to 22 bits) data acquisition to record time-domain interferograms which get converted to spectra on-board the spacecraft. Our previous work presented a system that utilized the Xilinx Virtex-4FX hybrid-FPGA to process raw interferogram data in a mixed HW/SWenvironment. We are now expanding the role of the FPGA to the analog data acquisition domain by interfacing it to high bandwidth, high data rate analog-to-digital converters. The quality of the collected data is verified by recording ground-based solar spectra with the existing JPL MkIV interferometer using the new acquisition system in parallel with the standard MkIV electronics. Processing time is reduced by upgrading to the Xilinx Virtex-5FXT FPGA.

The Geostationary Carbon Process Mapper

The Geostationary Carbon Process Mapper (GCPM) is an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The measurement strategy delivers a process based understanding of the carbon cycle that is accurate and extensible from city to regional and continental scales. This understanding comes from contiguous maps of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) collected up to 10 times per day at high spatial resolution (~4km × 4km) from geostationary orbit (GEO). These measurements will capture the spatial and temporal variability of the carbon cycle across diurnal, synoptic, seasonal and interannual time scales. The CO2/CH4/CO/CF measurement suite has been specifically selected because their combination provides the information needed to disentangle natural and anthropogenic contributions to atmospheric carbon concentrations and to minimize key uncertainties in the flow of carbon between the atmosphere and surface since they place constraints on both biogenic uptake and release as well as on combustion emissions. Additionally, GCPMs combination of high-resolution mapping and high measurement frequency provide quasi-continuous monitoring, effectively eliminating atmospheric transport uncertainties from source/sink inversion modeling. GCPM uses a single instrument, the “Geostationary Fourier Transform Spectrometer (GeoFTS)” to make measurements in the near infrared spectral region at high spectral resolution. The GeoFTS is a half meter cube size instrument designed to be a secondary “hosted” payload on a commercial GEO satellite. NASA and other government agencies have adopted the hosted payload implementation approach because it substantially reduces the overall mission cost. This paper presents a hosted payload implementation approach for measuring the major carbon-containing gases in the atmosphere from the geostationary vantage point, to affordably advance the scientific understating of carbon cycle processes and climate change.

Command and data handling system for the Panchromatic Fourier Transform Spectrometer

Panchromatic Fourier Transform Spectrometer (Pan-FTS) is an Instrument Incubator Program (IIP) funded development to build and demonstrate a single instrument capable of meeting or exceeding the requirements of the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission. Pan-FTS has recently started operation at Mt. Wilson, CA, providing atmospheric measurement capabilities in the IR and UV-VIS. The currently deployed instrument includes two Focal Plane Arrays (FPA): a Raytheon IR FPA and a JPL developed UV-VIS FPA. This paper discusses the major electronic and software components of the instruments FPGA-based command and data handling (C&DH) system. Progress made in the last year is discussed, with emphasis on the overall system architecture, FPA data acquisition, sigma-delta filter design, and optical path-difference mechanism (OPDM) control. Spectra recorded with single element detectors by PanFTS at Mt. Wilson are presented.