TARGET CLASSIFICATION AND REMOTE SENSING OF OCEAN CURRENT SHEAR USING A DUAL-USE MULTI-FREQUENCY HF RADAR

摘要

We describe an HF radar capable of multi-frequency operation over the HF band for dual dual- use application to ship classification and mapping ocean current shear and vector winds. The radar is based on a digital transceiver PCI card family that supports antenna arrays of four to 32 elements with a single computer, with larger arrays possible using multiple computers and receiver cards. The radar makes use of broad band loop antennas for receive elements, and a number of different possibilities for transmit antennas, depending on the operating bandwidth desired. An option exists in the choice of monostatic or multi-static operation, the latter providing the ability to use several transmit sites, with all radar echo signal reception and processing conducted at a single master receiver site. As applications for such a multi multi- frequency radar capability, we show measurement and modeling examples of multiple frequency HF radar cross section (RCS) of ships as an approach to target classification. Results of using 32 radar frequencies to measure of the fine structure in ocean current vertical shear are also shown, providing evidence of a water column eddy masked at the surface by wind driven shear. Other applications of current shear measurements, such as vector wind mapping and volumetric current estimation in coastal waters are also discussed.