UAV path planning optimization based on GNSS quality and mission requirements

One of the most crucial factors for the overall success of an Unmanned Aerial Vehicle (UAV) mission is navigation performance, which is severely affected in Global Navigation Satellite Systems (GNSS) challenging environments. A solution to this problem could come through path planning optimization. This paper investigates the impact that GNSS quality information included in the UAV path planning process would have on the overall UAV mission success rate (MSR) when flying through an urban canyon. Number of visible satellites and Horizontal Dilution of Precision (HDOP) in addition to mission-specific requirements are given as input to the Particle Swarm Optimization (PSO) algorithm to calculate the optimal path for two cases. One includes the GNSS observables, and the other does not. Optimal paths for three different altitudes are obtained. All paths are simulated by a GNSS signal simulator, including a comprehensive multipath model. GNSS data are collected by a hardware receiver for analysis of the UAV positioning error and GNSS availability. Mission failures cases are defined accordingly, and the overall mission success rate (MSR) of each scenario is assessed. By analyzing the findings, it is concluded that in 83% of cases, the path planning process that included GNSS information was able to increase the MSR. Also, the increase in MSR was bigger when flying at low altitude

Introduction to GNSS

This chapter is a primer on global navigation satellite systems (GNSSs). It assumes no prior knowledge of the systems or how theywork. All of the key concepts of satellite-based positioning, navigation, and timing (PNT) are introduced with pointers to subsequent chapters for further details. The chapter begins with a history of PNT using satellites and then introduces the concept of positioning using measured ranges between a receiver and satellites. The basic observation equations are then described along with the associated error budgets. Subsequently, the various GNSSs now in operation and in development are briefly overviewed. The chapter concludes with a discussion of the relevance and importance of GNSS for science and society at large