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Access Type
Open Access
Document Type
thesis
Degree Program
Electrical & Computer Engineering
Degree Type
Master of Science in Electrical and Computer Engineering (M.S.E.C.E.)
Year Degree Awarded
2009
Month Degree Awarded
February
Keywords
IWRAP, radar, scatterometer, pulse compression, hurricane hunter, Doppler
Abstract
The pulse compression scheme implemented on the Imaging Wind and Rain Air-borne Profiler (IWRAP) is described. Developed at the UMASS Microwave Remote Sensing Laboratory (MIRSL), IWRAP is a dual-band (C and Ku) conically scanning Doppler scatterometer designed to map the atmospheric boundary layer wind fields, ocean surface wind fields, and precipitation within tropical cyclones. IWRAP has previously been deployed using a pulsed transmit waveform with a peak transmit power of 80 watts. This limits the average transmit power and sensitivity for the system which affects the more distant range gates (especially at Ku-band). As a result, IWRAP could operate only at lower altitudes (approx. 5000 ft) causing safety concerns and limiting the missions for which it can be deployed.
Increasing sensitivity was achieved by converting IWRAP to a pulse compression radar system. Pulse compression is a technique that combines the increased energy of a longer pulse with the high resolution of a short pulse by implementing a frequency modulated (FM) “chirped” transmit waveform. This method requires advanced signal processing, in which the received signal is passed through a filter to compress the pulse on the receiving end. A system with various chirp/filtering schemes as well as a new control system which UMASS has recently developed will be discussed in this thesis.
DOI
https://doi.org/10.7275/690298
First Advisor
Stephen J Frasier