Multisource Fusion Method for Neutral Atmospheric Refraction Error Compensation in Ground-Based Distributed Radar

Ground-based distributed radar systems can overcome the physical constraints of traditional ground-based radar systems and enable precise detection and imaging of deep-space targets such as asteroids, by high-precision signal synchronization technique. However, the nonuniform refractive index of the neutral atmosphere deflects the synthetic beam of the ground based distributed radar, compromising the detection precision of deep-space targets. Existing neutral atmospheric refraction error (NARE) compensation methods still need to be improved in their applicability and accuracy for the ground-based distributed radars. To address the aforementioned issues, this paper first models and analyzes the impact of NARE on ground-based distributed radar systems. Then, a high-precision NARE compensation method for ground-based distributed radar is also proposed, which involves a hybrid refractivity profile model and a cost function for model parameter estimation. This cost function integrates line-of-sight atmospheric delay by global navigation satellite system meteorology (GNSS/MET) and numerical weather prediction (NWP) data to improve the accuracy of model parameter estimation and NARE compensation. Validation based on measured GNSS data shows that the proposed method attains a root-mean-square error (RMSE) of 0.0404 arc seconds in NARE compensation at a 15° elevation angle, representing an improvement of approximately 72% over traditional methods in precision. These results fully demonstrate the superiority of the proposed method for application in ground based distributed radar systems with baselines of several kilometers.