To enhance the cost-effectiveness and response time/position accuracy of cluster munitions targeting, this paper proposes a coordinated positioning model for cluster munitions based on GNSS/IMU+UWB information fusion. It constructs a “leader-follower” architecture for coordinated cluster munitions, utilizing the position, velocity, and acceleration data obtained by a determined number of leader equipped with GNSS/IMU modules, along with ranging information from UWB for the majority of followers, to dynamically calculate their positions. Monte Carlo simulations were conducted to analyze the nonlinear coupling relationship between the positioning accuracy of followers and factors such as the positioning error, quantity, and spatial configuration of leader. This paper provides theoretical support for the precise response and low-cost design of cluster munitions targeting.