Active Target Multistatic Receiver(ATMR)

John Paden

Project Background

• KU’s Center for Remote Sensing of Ice Sheets was awarded an NSF MRI grant to build a new 24-channel 150-600 MHz radar system

• Part of the award includes funds to build a calibration system for the new radar. This calibration system is called the “Active Target Multistatic Receiver” or ATMR

• The proposed EECS 502 project is to build a complete ATMR system.

WHY BUILD THE RADAR?

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Sea Level Rise

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Images from http://www.nsidc.org/

Ice Core Site Selection

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Image from http://www.nsidc.org/

Large Array

• 24-channel system composed of three 8-element subarrays

• Explore MIMO radar concept• Improved swath imaging

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Wide Bandwidth

• Wide bandwidth to resolve fine layering from the ice surface to the ice bottom.

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ay tra

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0.00 km76.381 N50.517 W

17.33 km76.451 N49.928 W

34.66 km76.520 N49.333 W

51.99 km76.588 N48.732 W

DistanceLatitude

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MCoRDS 20110329_02_020

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WHY BUILD THE ATMR?

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ATMR Motivation

• Monitor system health precisely• Array calibration of 24 element VHF-UHF

array difficult to impossible any other way• Channel equalization more critical

because of wide bandwidth (4:1)• Active target allows radiometric calibration

of radar AND processing system

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ATMR DETAILS

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System Operation

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time

signal

Tx Rx Tx Rx Tx Rx

Tpd TPRI

Fig. 1. Illustration of radar transmission (Tx) and reception (Rx) in normal operation mode.

time

signal

Tx Rx Tx Rx

TPRI

Cal CalFig. 2. Illustration of radar transmission and reception in calibration mode. The radar’s transmission is (Tx) which is captured by the ATMR and the radar receives both the scattered signal (Rx) and the ATMR’s calibration signal (Cal).

System Description

• Antenna– Use a single radar system antenna element– Calibration in anechoic chamber

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System Description

• RF Section– Create link budget for signal capture and

injection– RF system block diagram and design reviews– Specify, order and test RF components– Assemble and test RF system

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System Description

• Digital Section– HDL to build DSP– Signal processing design– Develop modules and test benches– Integrate modules and complete lab test

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System Description

• Clock Synthesizer– Build AWG and DAQ clock synthesizers

integrated to a GPS-synced oscillator.– Provide 1 PPS and position information to

digital section with GPS receiver.

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Final Integration

• Integrate RF and Digital systems• Lab tests• Radar tests

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Project Objectives

• Test with radar system and verify that captured signal and injected signal measure system impulse response at expected power levels

• Handle full 150 to 600 MHz bandwidth through pipelining and parallelization

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Skillsets

• Antenna calibration• Radio system (transmit/receiver) design

– RF component selection/testing• Digital signal processing: modulation,

filtering, detection• HDL• Lab equipment (setup and programming)

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