Airborne Imaging Line Scanner Modernization Patrick O’Brien Matthew Weinstock

Design Overview Modernizing a Vietnam War era scanner used to obtain visible and infrared images from low speed aircraft (converted from high speed aircraft (F-4 Phantom ‘Wild Weasel’) ran scanner from an aircraft speed near Mach 1 and obtained infrared images only)

Airborne Line Scanner

Two sets of mirrors: flat and curved Four flat mirrors rotated by variable controlled DC motor One stationary curved mirror and one stationary flat mirror Rotating flat mirrors obtain one dimension of the image, while aircraft’s forward motion provides the second dimension

Airborne Line Scanner Diagram Operation of Scanner

Photodiode Used as Spectrometer in Scanner

Photodiode

DC Motor Variable Controlled from DC source Maximum of 10 Hz Absolute shaft encoder used to determine position of motor (rotating mirrors) Enclosed in scanner chassis

PCB123 and Front End Analog Company used to design and produce PCB boards used in project Design program from PCB123 similar to that of P-Spice combined with VLSI design

Front End Analog Schematic

Absolute Shaft Encoder Precision guaranteed because every position is definable Able to obtain current position without needing a reference point Attached to scanner chassis through bracket

Analog to Digital Converter Portable USB-Based DAQ with Simultaneous Sampling (Windows) produced by National Instruments FIFO technology System made for continuous data acquisition Data held in continuous memory Needs to have 12-bit resolution, will have at most 16 bits of digital I/O

Analog to Digital Converter Sampling rate of A/D is at most 60,000 samples/second Sample rate = mirror speed * number of samples per revolution Maximum mirror speed is 10 Hz Number of samples is 6,000 A/D includes software drivers that will be customized for scanner

Controlling Unit ‘Briefcase Computer’ with AMD/Intel technology CPU will run ActiveX controls and Visual Basic Code which will control data input and motor control

ActiveX and the A/D ‘Click and Drag’ programming ability Wide variety of controls Interfaces with most technologies Will be used to interface A/D with the ‘Briefcase Computer’

Visual Basic Software and The Motor Visual Basic offers ease of design for GUI Processes will be triggered by movement and clicking of slider and buttons GUI will also relay information gathered from motor and encoder

User Interface User Interface: Start and stop system Controls how many times the flat mirrors will turn Controls the speed of the motor Will show a preview of the image captured, a numeric value for mirror speed, and the sensor temperature

User Interface

Questions