INTRODUCTION - EPS-A SERIES DESCRIPTION SENSOR UNIT -Scanner Module -Optical Description -Black Bodies -Gyro -Spectrometer Module -Optical Description -Electronics -Mechanical Description ELECTRONICS RACK -Workstation Module -Control Module -Recorder Module -Options AIRCRAFT INTERFACE -Mechanical Interface -Electrical Interface -Data Communications Interface SOFTWARE -HyperView™ -GER Preprocessing Software MANUALS APPENDIX -Technical Specifications -Mechanical Specifications -Physical Specifications -Environmental Specifications

EPS-A Series System with Standard Control Electronics (Shared by EPS-M, A, and H Series)

INTRODUCTION - EPS-A SERIES DESCRIPTION

The EPS-A SERIES Multi-Spectral Scanning System is based on modular components developed for the GER EPS (Environmental Probe System) and DAIS (Digital Airborne Imaging System) families of airborne imaging spectrometers such as the EPS 2100M, EPS 5100, DAIS 3715, DAIS 7915 and the DAIS 2815. The Sensor Unit consists of a Scanner Module based on our mid sized Kennedy Scanner and a custom Spectrometer Module configured to meet the specific applications requirements. The Electronics Rack Unit contains the Workstation Module, the Data Acquisition Module, the Controller Module and the Power Distribution Module. The Operator Interface consists of a Display, a Keyboard/Pointing Device, the Recorder Module and optional Auxiliary Video Output. The Aircraft Interface provides a custom Mounting Frame, Power Input and Data Interface connection. The GER EPS-A SERIES Software includes Hyperview™ real time control software loaded on the workstation for operation on board the aircraft and GER Preprocessing Software for post mission data preprocessing.

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EPS Scanner System
SENSOR UNIT

The Sensor Unit contains the Scanner and the Spectrometer. The Scanner defines the spatial characteristics of the acquired image while the Spectrometer divides the energy from a pixel on the ground into it's spectral components and transforms that energy into an electronic signal.

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Scanner Module

The Scanner Module is a "whisk broom" strip mapper. The optical scanner is based on the Kennedy Scanner, which consists of a multi-faceted rotating mirror. As the mirror rotates, the field of view changes and data are acquired across the flight track to form a scan line. Scan lines are accumulated along the flight track and a strip map image is produced.

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Optical Description

The Kennedy Scanner utilizes a dual optical path from a parabolic focusing mirror to obtain a large collection aperture and provide high scan efficiency. The two optical paths are aligned for co-registration and focus at infinity. The polygonal mirror provides four (4) scan lines per mirror revolution. The mirror is driven directly by a DC Servo motor and includes a high resolution Digital Rotary Encoder for velocity and absolute positioning feedback to the Controller and Data Acquisition Modules.

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Black Bodies

Temperature Controlled black bodies are mounted on either side of the Scan Head for real time baseline correction and Thermometric Calibration. A remote temperature sensor monitors the temperature of each black body. The temperature data are used for feedback to the temperature controllers and are recorded in the Housekeeping Data Channel.

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Gyro

A multi-axis solid state gyro system is provided for image geo-correction. Roll correction is applied in real time. Other data can be used for subsequent geocorrection during ground processing with appropriate software.

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Spectrometer Module

A typical GER EPS-A SERIES Spectrometer might include four (4) optical paths and thirty-one (31) channels of spectral information. The Field of View of all spectral bands is determined by a single aperture, so unlike other commercial imaging spectrometers, all channels of the GER spectrometer are fully co-registered assuring accurate measurement of spectra within each individual pixel without additional spatial corrections. A user selectable aperture is available as an option. A schematic version of the spectrometer configuration is shown below. Alternative band configurations are available for this system. The spectrometer unit contains all optical components, detector/cooler assemblies, and preamplifiers required for parallel measurement of all defined spectral bands.

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Optical Description

The spectrometer is coupled to the Kennedy scanner via a selectable aperture (2.5 mr nominal) that determines the instantaneous field of view of the system. The light passing through the aperture is split by a precision beamsplitter into a thermal component, which is collimated and focused onto the thermal detector. The reflected light is collimated and further divided by additional spectral splitters to the individual grating spectrometers. In the grating spectrometers, the light is directed to a diffraction grating that separates the collimated beam into its spectral components. These components are focused onto an appropriate detector array with elements aligned to the desired wavelength positions. The following table illustrates the configuration of each of the spectrometers.

Sample Band Configuration

Spectrometer Number	Region	Wavelength Region (µm)	# of Bands	Detector Type	Detector Cooling
1	VIS/NIR	.4 - 1.05	28	Si Array 76 Element
2	SWIR1	1.8	1	InGaAs	TE
3	SWIR2	2.2	1	InGaAs	TE
4	TIR	8.0 - 12.5	1	HgCdTe	Closed Cycle

*Several band configurations available.
Detailed band specifications to be defined with customer.
Multiple thermal bands are available in the pour filled LN₂ dewar configuration (MCT). Back to Table of Contents

Electronics

All detector modules employ integrated preamplifiers to maximize noise immunity. Second stage amplification and cable driving circuitry are provided for each channel to provide robust signal levels to the Electronics Rack Unit. A single DC voltage is provided to the spectrometer from the Power Distribution Module. A local spectrometer power distribution board generates all required power in the spectrometer. All analog power is isolated from potential noise sources. Electrical connection to the spectrometer head is made through locking, airborne compatible high-density signal connectors.

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Mechanical Description

The spectrometer module is a sealed unit that can be conveniently opened for maintenance if required. The spectrometer module can be removed from the scan head module and reinstalled if required without loss of optical alignment. The enclosure is environmentally sealed and a desiccant is provided.

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ELECTRONIC RACK

The Electronics Rack Unit uses a 19 inch Rack Mountable, industry standard VME backplane enclosure to house the Workstation Module, the Data Acquisition Module, the Controller Module, the Recorder, Power Distribution Module, and any auxiliary electronics, such as optional GPS receiver and Video Output Modules.

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Workstation Module

The core of the workstation module is a dual Ultra Sparc CPU. All software required for operation of the Multi-Spectral Scanner resides on the workstation's hard disk. The workstation, using operator input into HyperView™ software, coordinates all MSS control, data acquisition, data recording, and data display functions. The workstation interfaces to the Data Acquisition Module via the VME bus. Data are read from the A/D board and recorded to tape and/or displayed in real time on the scrolling waterfall display. The recorder interface is the standard SCSI bus, allowing recorders to be upgraded as recorder performance improves. The workstation also receives data from the aircraft's GPS receiver via a serial communications port. This data is displayed with the real time MSS data and recorded the embedded Housekeeping Channel. This is shown below.

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Controller Module

The controller module consists of the scan mirror controller and the black body controllers. The controllers are intelligent control systems that are programmed via the user interface of the Hyperview™ Software and provide real time control. The scan mirror controller uses the encoder feedback to precisely control the motor speed. The black body controllers use feedback from the remote black body temperature sensors to provide stable black body temperatures.

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Recorder Module

The recommended recorder is an Exabyte Mammoth recorder. The recorder is mounted in the Electronics Rack Unit and is powered by DC voltages derived the Power Distribution Module. The Data interface to the recorder is via industry standard high speed SCSI.

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Options

Optional electronics that can be added to the Electronics Rack Unit include, but are not limited to, a dedicated GPS receiver to interface to a GPS antenna, video converters to provide video feeds to auxiliary consoles in NTSC, RGB, etc. formats. The industry standard VME architecture provides great flexibility in fulfilling custom additions to the MSS Scanner System.

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AIRCRAFT INTERFACE

Mechanical Interface

The Sensor Unit is provided with a shock and vibration isolated mounting frame. This frame is designed to meet the mounting requirements of a specified aircraft. The electronics rack enclosure and display are standard mountable devices. They mount directly in standard 19-inch racks.

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Electrical Interface

The power required for the system is derived from the aircraft system 28 V DC power supply. The power distribution module within the Electronics Rack Enclosure supplies all system voltages.

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Data Communications Interface

The GPS data stream connects to the MSS via the data communications interface. The connection is an RS422 serial data stream. The data stream can be Extended King (X0), King (K0), or TBD (R0). Custom interfaces can be provided optionally.

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SOFTWARE

HyperView™

GER'S HyperView™ software provides a simple graphical interface for the operation and monitoring of the GER EPS-A SERIES Scanning System. System status may be monitored, real-time image data displayed, and system parameters set from a simple menu driven user interface. Running on the embedded SPARC workstation, HyperView™ provides a versatile tool for both data acquisition and monitoring/enforcement applications requiring real-time data display and interpretation. HyperView™ can also be used for mission playback and additional licenses may be purchased for use on ground based stations. GER will provide Hyperview software updates without charge during the warranty period.

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GER Preprocessing Software

Preprocessing software is provided for data preprocessing on a ground workstation with a DLT 7000 attached. The Preprocessing software runs on the Solaris 2.6 operating system and provides a simple user interface. The preprocessing software provides the user with tape reading functions and preprocessing functions. The tape reading function reads data from the DLT 7000 and stores the flight data to disk. This data can then be preprocessed for viewing with standard image processing software packages. The preprocessing software applies baseline corrections, roll gyro corrections, panoramic corrections, and radiometric/thermometric calibration conversions. The output data format is Band Interleaved (BIL).

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MANUALS

GER will supply the following manuals at the time of training at the Millbrook facility:

Installation Manual

Operations Manual

Maintenance Manual

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APPENDIX

Technical Specifications for Sample Configuration

Wavelength Range: 0.4µ to 12,5µ, 31 bands	0.4µ - 1.05µ       : 28 channels* 1.8µ                   : 1 channel* 2.2µ                   : 1 channel* 8.0µ - 12.5µ Detailed bands width / placements to be specified with customer
Optical Collecting Aperture	130cm2 (sensor aperture)
IFOV	Selesctable - 2.5mRad / 1.25mRad Other apertures optional
System Swath Angle	75° minimum
System Scan Speed	Up to 60Hz all bands Up to 100Hz - subset of bands Scan Speed is limited by data recorder
Pixels per Line	Approx. 732 (nominal) (up to 1024 - software controlled)
Recording Media	Exabyte Mammoth or other SCSI compatible 5Mb/sec Up to 20Gb capacity
System Controller	Dual Ultra SPARC workstation High resolution color monitor RS422 I/O ports are available for GPS information and peripherals (printers, plotters, etc.)
Detectors	VIS/NIR - Si:  U.V. enhanced array SWIR 1 - InGaAs element thermoelectrically cooled SWIR 2 - InGaAs element thermoelectrically cooled Thermal MCT:  closed cycle
MTBF	28V, 50Amp standard aircraft power
Thermometric Calibration	Two on-board blackbodies
Geometric Correction	GPS System Roll gyro system is standard 3 axis gyro (option)
Absolute Positioning	Ground processing software for roll and panoramic Geo-correction provided
Digitization	16 bits

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Physical Specifications

Weight:

Scan Head / Spectrometer	120lbs.
Electronics (includes thin film display and trackball / keyboard)	100lbs.

Dimensions (approximate):

	Height	Width	Depth
Scan Head / Spectrometer	20"	20"	23"
Electronics (excluding display)	35"	19"	20"

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Environmental Specifications

Under Operation:

	Temperature	Realtive Humidity
Radiometric and Scanning Unit	-20° to 60°C	0 to 95% (non-condensing)
Color and Monitoring System	-10° to 40°C	0 to 95% (non-condensing)

Out of Operations:

	Temperature	Realtive Humidity
Radiometric and Scanning Unit	-40° to 60°C	0 to 95% (non-condensing)
Color and Monitoring System	-40° to 60°C	0 to 95% (non-condensing)

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