Discretize-Then-Optimize Approach to Real-Time Tropospheric Refractivity Inversion

This study proposes a tomographic method for tropospheric refractivity estimation. Step-by-step numerical scheme for the parabolic equation is considered as a computational graph. The gradient required for efficient inversion is computed using the method of automatic differentiation. Instead of inverting a single static profile, the process of profile variation over time is simulated and tracked. Numerical experiments were conducted for various profiles, frequencies, and receiver antenna parameters. The results demonstrate the adequacy, high performance, and robustness of the proposed approach.