This dissertation details the design and operation of the FOcused Phased Array Imaging Radar (FOPAIR) intended for high-resolution ocean surface imaging applications. This radar is unique in its capability to produce coherent microwave imagery with both high spatial and temporal resolutions. Such resolution is required to yield an accurate representation of the ocean surface as it appears at X-band wavelengths. Both the principles of operation and the hardware design of the radar are presented. Methods for phase calibrating the array are shown that permit focused images to be generated from the acquired radar backscatter. The resulting sidelobe level performance and the anticipated sensitivity of the radar are shown, and sample images of the ocean surface illustrate its ability to image ocean wave patterns. Because FOPAIR produces complex radar imagery at high speeds, radial velocity can be estimated at each pixel location. Through appropriate processing it is shown that FOPAIR should be capable of absolute measurement of the directional spectrum of ocean surface wind waves. To test this hypothesis and to validate that FOPAIR imagery is an accurate representation of the ocean surface, a field test was conducted in which radar measurements of the wind wave directional spectrum were compared to simultaneous directional wave measurements made by a nearby array of pressure sensors mounted on the sea floor. Comparisons between both systems over 18 trials show correlations exceeding 95% for measurements of dominant wave length, wave direction, and total wave energy. These results support the hypothesis that radial velocity derived imagery can be used to estimate the directional wave spectrum and provide confidence in FOPAIR's sensitivity to the ocean surface wind-wave field.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8957 |
| Date | 01 January 1994 |
| Creators | Frasier, Stephen James |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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