Refraction correction for downlooking radio wave and its application in the signal reception for downlooking radars

This paper studies an effective shipboard maneuvering receiving method for shore-based down-looking radar signal influenced by atmospheric refraction environments over the ocean. According to the actual demands, a physical propagation model of down-looking radar signal over the ocean is established. Using ray tracing method and Hopfield refractive index profile model, this paper simulates the electromagnetic wave propagation path influenced by atmospheric refraction environments. Compared with the calculation results of Ray-VT ray tracing software, the relative deviations of the horizontal distance under four emission parameters are -0.002%, -0.041%, -0.029%, and -0.007%, respectively, which preliminarily illustrates the accuracy of simulated propagation paths. It is found that the atmospheric refraction environment over the ocean has a great influence on the effective ship-based reception of the shore-based down-looking radar signal. Therefore, the receiving position and pitch angle must be corrected.