A Velocity Dealiasing Algorithm on Frequency Diversity Pulse-Pair for Future Geostationary Spaceborne Doppler Weather Radar

Abstract

Velocity ambiguity is one of the main challenges in accurately measuring velocity for the future Geostationary Spaceborne Doppler Weather Radar (GSDWR) due to its short wavelength. The aim of this work was to provide a novel velocity dealiasing method for frequency diversity for the future implementation of GSDWR. Two different carrier frequencies were transmitted on the adjacent pulse-pair and the order of the pulse-pair was exchanged during the transmission of the next pulse-pair. The Doppler phase shift between these two adjacent pulses was estimated based on the technique of the frequency diversity pulse-pair (FDPP), and Doppler velocity was estimated on the sum of the Doppler phase within the adjacent pulse repetition time (PRT). From the theoretical result, the maximum unambiguous velocity estimated by FDPP is only decided by the interval time of the two adjacent pulses and radar wavelength. An echo signal model on frequency diversity was established to simulate echo signals of the GSDWR to verify the extension of the maximum unambiguous velocity and the accuracy of the velocity estimation for FDPP used on GSDWR. The study demonstrates that the FDPP algorithm can extend the maximum unambiguous velocity greater than the Stagger PRT method and the unambiguous range and velocity are no longer limited by the chosen value of pulse repetition frequency (PRF). In the Ka band, the maximum unambiguous velocity can be extended to 105 m/s when the interval time is 10 µs and most velocity estimation biases are less than 0.5 m/s.

Satellite Velocity Correction Method of Ocean Current Retrieval for a Spaceborne Doppler Scatterometer

“…The pulse-pair method only involves signal processing in the time domain. Because of this simplicity, it is widely used for estimating Doppler frequency from backscattered signals in Doppler weather radar [37,38].…”

“…𝐺 = 𝐺 𝜃 , 𝜑 . (37) and the correction of the platform velocity is given by 𝑣 𝜃, 𝜑, 𝑣 = −𝑣 𝜃, 𝜑, 𝑣 = − 𝑣 𝜃, 𝜑, 𝑣 . (38) Using Equation ( 38), we can calculate the offset of the Doppler centroid, considering the influence of antenna pattern modulation.…”

Signal Simulation of Dual-Polarization Weather Radar and Its Application in Range Ambiguity Mitigation

“…Similarly, Feng et al simulated the effect of degraded antenna pattern sidelobes based on simulation signals [9]. For echo signal simulation, the simulation method based on the Gaussian power model for Doppler weather radar is established, which can simulate the signal of single-polarization doppler weather radar based on echo power, radial velocity, and spectral width [10]. For dual-polarization weather radar echo signal simulation, David Schvartzman et al proposed a novel dual-polarization weather radar echo simulation method, which can simulate the echo through the data collected by the WSR-88D radar [11].…”