Performance Analysis of a Multi-Slope Chirp Spread Spectrum Signal for PNT in a LEO Constellation

During the past few decades, the use of global navigation satellite systems (GNSSs) has become the primary and sometimes only way of providing a positioning, navigation, and timing (PNT) solution for many outdoor applications. Further-more, GNSS is playing an important role on the development of smart cities and Internet of things (IoT) applications. For this reason, seamless navigation has become very crucial for numerous PNT-dependent applications. Unfortunately, GNSS is a technology that is vulnerable to several threats. All these ingredients boil down to the need for alternative PNT solutions to backup GNSS in case of miss performance or denial of service. The use of low earth orbit (LEO) constellations has been considered in the literature to provide global solution, but more importantly because it will bring some benefits with respect to medium earth orbit (MEO); which is the constellation used in GNSS. Based on these considerations, in this paper we focus on the design of a new PNT signal for LEO constellations. Furthermore, a comprehensive performance analysis is carried out with the aim of reducing the receiver complexity. For that, a chirp spread spectrum signal design is considered.