FPGA-based data acquisition system for GNSS receiver for LEO-satellites applications

Abstract

The modern Low Earth Orbit satellites (LEO-satellites) technology is highly complex and reliable than it was yesterday. Nowadays, the LEO-satellites applications extend from civilian to military applications. However, LEO-satellites require a Global Navigation Satellite System (GNSS) service, to achieve various tasks which require positioning and localizing. The challenge is to have a GNSS receiver that is sensitive enough to process weak GNSS signals, as they are buried inside the Doppler frequencies. Therefore, a specialised data acquisition system for space environment, is utilized in the GNSS receiver to search for visible satellites. However, when it comes to which acquisition algorithm that is suitable for LEO-applications, what matters the most is the Doppler range. That is to say, any algorithm would work, as long as higher Doppler frequency is considered in implementation. But, some algorithms are better and faster than others. On the other hand, the platform in which algorithm is implemented on, does affect the system performance. The FPGA-based data acquisition can only implement a few of the available algorithms. In this project, we focused on serial search algorithms, which seems to be implementable on FPGA.