Ultrasonic InSAR System Brandon Ravenscroft 12/04/2015

Objective Develop an InSAR system operating in the ultrasonic range, specifically from 30 – 50 kHz Adapt a previously designed and built system to function on two different platforms Spotlight: stationary transmitter and receiver, target rotates on fixed platform. Measurements taken at fixed degree intervals. Stripmap: Side looking. Target fixed and transmitter/receiver moves along x-axis. Measurements taken at given intervals

System Functionality Chirp signal generated by Arduino or other microprocessor using DDS or AWG and output on DAC Signal is amplified and launched through a transducer Backscatter is received through a separate transducer and amplified Stretch processing performed on received signal Down converted signal sampled by microprocessor ADC (2 channels on Due, up to 4 on DSO) and stored/transferred serially to computer/observed on DSO

System Parameters v P = 343 m/s Transmit signal: Linear FMCW Chirp f = kHz (λ = 11.4 mm – 6.86 mm) B = 20 kHz τ = 500 ms nominally (Bτ = 10000) Programmable start and stop signal frequencies Programmable pulse duration and initial phase Transmit Antenna: Kobitone ST16-ROX Ultrasonic transducer with 35.2 degree 3 dB beamwidth Receive Antenna: 16 element linear array of Knowles SPU0410HR5H-PB ultrasonic transducers spaced at λ/2 between phase centers for 50 kHz (~ 3 mm)

System Parameters

Spotlight Platform Diagram

Stripmap Platform Diagram (Overhead)

System Block Diagram

Receive Antenna 16 Elements allow for adjustable baseline

Existing System

Future Work Complete system diagrams with detailed specifications and geometries Finish specifying system parameters Operation procedures Simulations Compile as detailed as possible report Hand design off to someone else