A Proposal of Pulse-Pair Doppler Operation on a Spaceborne Cloud-Profiling Radar in the W Band

Abstract

Pulse-pair Doppler operation is considered for the spaceborne mission. In a formalism, the condition that a measured Doppler velocity on pulse-pair operation corresponds to that on the FFT operation is derived. The coherent coupling effect of the spectral broadenings between Doppler fading and vertical wind shears is shown to strongly depend on the flight direction of a platform. This coupling effect, which has been ignored for ground-based and airborne radars, is characteristic for the space mission. Two kinds of pulse-pair operations, polarization diversity method and conventional contiguous pulse-pair method, are studied to determine the accuracy of Doppler velocity as a function of cloud reflectivity and pulse-pair interval. Advantages and disadvantages of these operations, including adverse effects of beam-pointing error, ground clutters, and sidelobes, are discussed along with a variety of parameters to design the optimum operation. In the assessment of the Doppler feasibility, new features suitable to the space mission are also proposed.