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GEOSCAN MK2 Scanner Specification

Resolution                                 3 Milli radians. 17 Meters at 10,000ft to 2.5 Meters at 3,000ft

Pixels                                        768 re-sampled to 1024 to correct for panoramic distortion.

Image Corrections                     Atmospheric back scatter.

                                                 Hardware data formatting from band interleaved by pixel to band interleaved by line.

Telescope                                  Three Front surfaced aluminum mirrors.

Spectral Filtering                        Two Diachronic filters and three diffraction gratings

Cooling system                          Helium and High pressure, high purity Nitrogen Gas. E/G size gas bottlea.

Visible Spectrometer                  10 Channels 0.45 to 0.9 micron, Blue/Green/Red 2 x False Color Infrared

    Detector                                32 element linear photovoltaic Silicon diode array.

    Lens                                      Quartz

SWIR Spectrometer                  8 Channel 2.0 to 2.5 micron.

    Detector                                8 element Indium Antimonite detector array. 

    Cooling                                 Joule Thompson cryostat / Sterling cycle engine.

    Lens                                      Zinc Salonide

Thermal Spectrometer                6 channel 8.5 to 12 micros.

    Detector                                8 element photovoltaic Mercury Cadmium Telluride detector array.

    Cooling                                 Joule Thompson cryostat

    Lens                                      Germanium

Stabilization                               3 Axis inertial stabilization system

    Roll                                       Electronic Start scan offset, 2 milli radian. Vertical gyro reference.

    Pitch                                     Mechanical servo control loop. Vertical gyro reference.

    Yaw                                      Mechanical servo control loop. Integrating rate gyro.

                                                 Manual Drift offset.

    Controller                               7 Slot custom servo control loop electronics rack.

Scan Speed                               Aircraft True air speed / Height controlled.

                                                 Brush less DC type ring motor with samarium cobalt magnets

Computer                                  Dial 32 bit 68020 VME computer.

                                                 2 by commercial 68020 Single board computers.

                                                 2 by commercial SMD hard disk controllers.

                                                 2 by commercial SCSI controllers.

                                                 1 by custom oscilloscope vector display controller.

                                                 1 by stabilization control system.

                                                 3 by custom 8 channel data aquisition controllers.

                                                 2 by custom VME to VME bridge.

                                                 2 by custom video controller.

Data Acquisition                        24 Channel, 8/12 bit sample and hold ADC.

                                                 Digital 8 bit gain, 8 bit log offset.

    Data Storage                          Two by 330M Byte 8" Hard disk drives. Upgraded to two 1G 5 1/4" SCSI disks.

    Data Backup                          5 1/4" 350M Byte WORM disk.

    Diagnostics                           Real time Digital Oscilloscope.

                                                 Real time histogram.

                                                 Real time spectrum analyzer.

                                                 Automatic voltage, current and temperature monitoring.

Image Display                            3, 6, 12 and 24 channel Real time scrolling display.

    Resolution                             512 pixels by 512 lines interlaced.

    Color                                     24 bit + 8 bit lookup table mask.

    Lookup table                          8 Hardware lookup table

    Controls                                Hardware pan scroll and zoom. Track ball interface.

Software                                   Written in 68020 Assembler and C.

                                                 Fully automated data acquisition and backup process with a Text Base GUI.


Authors Contribution 

Electronics                                Data Acquisition system 

                                                 Computer hardware.

                                                 Inertial stabilization system.

                                                 Video controller hardware.

                                                 Aircraft interface.

                                                 Low noise front end.

Electrical                                   Power supplies, power distribution, control.

Software                                   Micro kernel, Data Acquisition, 

                                                 Automated control system, Data correction, 

                                                 Data storage and archiving, Aircraft interface. 

                                                 User command line interface. Image processing Software

Miscellaneous                            Fix optical and mechanical design flaws. 

                                                 Scanner Operator for three Years.


Photo gallery 

GEOSCAN MK2 Scanner ten visible spectral bands.

GEOSCAN MK2 Scanner eight SWIR spectral bands.

  GEOSCAN MK2 Scanner six thermal spectral bands.

MK2 Scanner control electronics prototype frame.

CESSNA 404 Fitted with a nose mounted high resolution drift site video camera. Built in 1980 using 1950's technology. We called the 404 a flying fuel tank. We could stay airborne for almost 12 hours using survey engine settings. The 404 was the best aircraft I ever piloted. It staggered off the end of the runway but was reluctant to land. 

CESSNA 404 cockpit fitted with a drift site monitor on the copilots seat. The MK2 Scanner crew consisted of a pilot/navigator and a scanner operator. The motivation for replacing navigator and the drift sight telescope with a video camera was to maintain access to the co-pilot controls. Many hours were clocked up in the right hand seat impersonating the autopilot.

GEOSCAN MK2 Scanner stabilization platform fitted to the CESSNA 404 camera hole.

MK2 Scanner aperture viewed from underneath the CESSNA 404.

MK2 Scanner telescope supported by the stabilization platform.

MK2 Scanner spectrometer diffraction grating, lens, linear array, cryogenic cooling system and low noise amplifiers.

MK2 Scanner real time oscilloscope/Spectrum analyzer controller prototype.

Mk2 Scanner wire wrapped computer prototype

MK2 Scanner real time Oscilloscope/histogram and spectrum analyzer display.

MK2 Scanner Dual VME computer electronics and real time image display. The MK2 Scanner data acquisition system could also function as a standalone airborne image processing system. Operational decisions were made by an onboard geologist or customer based on the real time image display.

GEOSCAN MK2 Scanner promotion image.

  GEOSCAN MK2 Scanner Image of Wyloo Pilbra Western Australia


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