Introduction

Doppler Navigation System with a Non-Stabilized Antenna as a Sea-Surface Wind Sensor

“…If periods of turbulence are rather short, for practical purposes, it would be easier to eliminate these measurements from further analysis, than to develop a dedicated correction, that would appear quite complex due to nonlinear character of turbulent flows. Uncertainties in the mounting angle of the antenna beam are very low as well, typically not exceeding 15 angular minutes [ 24 , 25 ]. As the NRCS curves are quite smooth, especially in the horizontal plane, they have an inessential impact on wind measurement results.…”

“…The center frequency of this band is 13.325 GHz. Two other bands, in particular, centered at 8.8 and 9.8 GHz, respectively, have been used in earlier DNS designs, while currently they are no longer applied in standalone Doppler radar design [ 24 ]. Typically, the DNS utilizes either three-beam λ -configured (beams 1, 2, and 3) or four-beam x -configured (beams 1, 2, 3, and 4) antennas, directed as shown in Figure 1 [ 27 ].…”

“…The effective beamwidth θ b of the DNS antenna is between 3° and 10° [ 27 ]. The typical mounting angle for the antenna beam axis in the vertical plane θ 0 is between 15° and 30° [ 24 ]. In the horizontal plane, the mounting angle of the antenna beam axis Γ 0 is between 15° and 45° [ 28 ].…”

“…In the horizontal plane, the mounting angle of the antenna beam axis Γ 0 is between 15° and 45° [ 28 ]. In the inclined plane, the beam axis mounting angle η 0 (angle between the longitudinal axis of the antenna and the central direction of the beam) is between 65° and 80° [ 24 ]. Every DNS beam provides the same angular resolutions in the vertical and azimuthal planes, Δ θ and Δ α , respectively.…”

“…One promising airborne radar instrument for such an application is the DNS. The system is equipped either with a fixed antenna, which is the most common solution in modern DNS designs, or with a track-stabilized antenna with additional its roll and pitch stabilization [ 24 ]. The DNS operation with a fixed-antenna system appears more difficult due to lack of its track stabilization.…”