In a complex geomorphic environment where satellite signals are severely interfered with, due to the small number of visible satellites and poor satellite signal quality, the accuracy of single-mode satellite positioning and navigation has been unsatisfactory, especially for dynamic navigation and positioning accuracy. In order to improve the accuracy of dynamic navigation and positioning, a multi-mode GNSS pseudo-range combined positioning algorithm was designed, which belonged to an iterative combined positioning algorithm. The initial iterative weight matrix was determined by the height angle priori weight model, and the weight was the smallest. In the process of the two multiplication method, the posterior model was estimated by the variance component, and the weight matrix was continuously updated iteratively to obtain the accurate position of the target. The algorithm needed to rely on the initial value and multiple iterations, but the positioning accuracy was better than the Gauss-Newton iterative algorithm and Helmert variance component estimation method. Experimental simulation results show that compared with Gauss-Newton iterative algorithm and Helmert variance component estimation method, the positioning accuracy of the algorithm designed in this paper is improved by 45.1% and 23%, respectively. Finally, combined with the actual airdrop test analysis, it is shown that the algorithm described in this paper can accurately calculate the drop point of the airdrop material, which can provide a reference for the aircraft navigation system designer, and has certain theoretical significance and practical value.