On The Complexity of Non-Coherent Acquisition of Chirp Spread Spectrum Signals.

During the past few decades, the use of GNSSs has become the primary and sometimes only way of providing a positioning solution for many outdoor applications. Furthermore, GNSS is playing an important role on the development of smart cities and Internet of things (IoT) applications. Unfortunately, GNSS is a technology that is a very hungry technology thus challenging its adoption in many IoT application. All these ingredients boil down to the need for alternative positioning solutions to backup GNSS. The use of low-Earth orbit (LEO) satellite constellations has been considered in the literature for that purpose. Chirp Spread Spectrum (CSS) modulation is a different approach to classic GNSS to enable positioning with LEO satellites. This type of signal is intended to address low-complexity positioning for IoT devices, tackling the complexity issue of the classic GNSS acquisition. In this paper, we consider the analysis of the non-coherent acquisition of CSS signals and its complexity is compared to its coherent counterpart.