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PROJECT OVERVIEW. Peter Hansen 734-763-6241 pehansen@umich.edu. System Requirements. L-band NEDT: < 0.1 K desired, < 0.5 K required Absolute calibration: < 2 K desired, < 3 K required Linear dynamic range: 5 K < Tb < 300 K Ambient operating temperature range: -30 o C < To < +40 o C
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PROJECT OVERVIEW Peter Hansen 734-763-6241 pehansen@umich.edu
System Requirements • L-band NEDT: < 0.1 K desired, < 0.5 K required • Absolute calibration: < 2 K desired, < 3 K required • Linear dynamic range: 5 K < Tb < 300 K • Ambient operating temperature range: -30o C < To < +40o C • Unpowered survival temperature range: -50o C < To < +60o C • Across-track scan width: ±35o • Synthesized half-power beamwidth: < 15o desired, < 22orequired • Onboard uninterrupted data storage for 3 hours • In-flight “Data OK” indication for pilot • TIR profiles – by synthesized beam desired, nadir required • Instrument provides flightline guidance, location, and attitude • Field maintainable, 2 month MTBF
System Implementation • System Designed to Interface with Aviat Husky Model A-1B aircraft • L-band Synthetic Thinned Array Radiometer (STAR) • Direct Sampling Digital Radiometer (DSDR) technology • Two major hardware modules • Sensor Module • Antennas, Receivers, Calibration Sources, Thermal Control, Timing & Data Sample Control • Control Module • Control Computer, Filter/Correlator,System I/O,Data Storage, Heat Exchanger, Power System • In-flight calibration sources - two widely spaced temperatures • Simple pilot/operator interface • On/Off power switch and power monitor • System ready, Data OK lights • On board raw data storage • Data analysis performed off-line • GSE • PC Laptop for offline data analysis, calibration • Shipping Containers • Handling Fixtures • Truck Boom Adapter
Technical Challenges • Tight Receiver Thermal Control Requirement • Temperature stability ~11 milli-degrees K during 1.5 sec integration period • Wide environmental operating temperature = -30 to +40 deg C • Rapid environmental temperature change from takeoff to cruise altitude • Tight Electrical Power Budget • Total available 12 Volt power = 400 Watts max, 300 Watts average • Receiver=100W, Thermal Control=100W, Control Module=200W • EMI/RFI • Small Aircraft Power System & Avionics • ECL electronics at VHF clock rates • Calibration • Absolute temperature accuracy <2 deg K
Project Plan • Development Phase - 2 Channel Prototype • Includes both Calibration sources - Diode (warm) and Cold • 2 Complete Receivers • LNA and Analog Filter evaluation • Cal source switching evaluation • A/D converter, system timing, digital signal processing evaluation • 10 Channel Thermal Control Prototype • Two active receivers, 8 resistive thermal simulators • PID controller evaluation • Prototype Control Computer Assembly • Early software development tool • High speed communications interface verification
Project Plan • Implementation Phase - 10 Channel Flight System • Fab and Test flight components • Integrate components • System Module testing - (Sensor Module, Control Module) • Use Prototype hardware for test support of flight modules • Continue software development • System Integration, Test and Calibration • GSE Fabrication • Mechanical fixtures and truck boom adapter • Field EGSE - power cart, pre-flight data analysis software • Flight Test Phase • Aircraft Integration • Flight Calibration • Field Evaluation
Prototype Development Plan • Stage 1 - Two parallel activities • Thermal Control System • Cold Plate, 10 Control Plates, Heat Exchanger, Plumbing • “Slow” versions of Receiver DA Board, Sensor Control Board • “Slow” version of PC104 Controller • Prototype Harness and Wiring • Thermal Control Software Development • Receiver RF System - 2 RF channels & Calibration Equipment • RF amplifiers, filters, and switch • Diode Noise Source & Dividers, Cold Cal Source • RF Characterization testing • Continued module thermal characterization
Prototype Development Plan - contd. • Stage 2 • Thermally controlled receiver • “Fast” version of Receiver DA Board, Sensor Control Board • “Fast” version of PC104 Controller • Integrated Receiver Tests • Signal Processing Software Development • Environmental temperature test • End to End Receiver Evaluation • Flight Hardware Design updates