## 1 Introduction
This factor is reflected also in the related EGSEs, with a consequent slowdown of the whole process of testing and using the protocol. Specifically, for what concerns CCSDS 131.2-B-compliant receivers, the state-of-the-art solution is represented by the Cortex High Data-Rate Receiver (Cortex HDR) [14]. It is a complex system developed by SAFRAN, which may be used in ground stations for receiving transmissions compliant with the protocol, but also in test facilities to test transmitters' capabilities before satellite launch. Although the Cortex HDR is a complete solution for employing the CCSDS standard, its high cost strongly limits its deployment. Indeed, as with other HW-based solutions, the Cortex HDR can cost hundreds of thousands of dollars, making its procurement unfeasible for most of the private companies and for agencies as well. In fact, not all the ground stations can be equipped with not one but many of these receivers, for multiple missions. Nonetheless, the high cost also limits the use of the receiver for testing standard-compliant transmitters. In the ESA roadmap for EO, the CCSDS 131.2-B standard has been selected to be the reference standard for future missions. For this reason, it is necessary to dispose of EGSEs compliant with this standard, for testing on-board and on-ground systems capable of adhering to the CCSDS 131.2-B. Also, it is crucial to provide low-cost systems to allow a wide adoption of the standard, opening its use to different subjects in the scope of the New Space Economy. With this in mind, this paper presents the work carried out for developing a low-cost CCSDS 131.2-B-compliant receiver based on a software implementation. This manuscript aims to extend the preliminary results presented in [15], where an exploratory implementation of the decoder part of the receiver, the object of this paper, was presented first with a discussion of its speed performance. In this paper, a detailed description of the whole architecture of the system will be given, focusing on its performance, both from error correction and decoding speed points of view. The presented receiver exploits the use of graphics processing units (GPUs) for developing a software-defined radio (SDR) solution capable of reaching high performance while maintaining a high level of flexibility with a much lower cost with respect to the state-of-the-art solutions. This system would allow for the easy and low-cost testing of CCSDS 131.2-B compliant systems, promoting the adoption of this standard for future mission. Also, for missions where requirements are relaxed, as science missions, a SW receiver would be an easy-to-deploy alternative to the state-of-the-art receivers. The remainder of this paper is organized as follows:  
* Section 2 describes the CCSDS 131.2-B protocol, focusing on the reason for its definition and the architecture of compliant transmitter and receiver systems;
* Section 3 delves into the details of a receiver system compliant with the standard, describing the rationale for implementing an SW-based solution and the development of its main parts;
* Section 4 shows the performance of the system in terms of both error correction and data rate, compared with the state of the art of CCSDS 131.2-B receivers;
* Section 5 draws the conclusion of the work and outlines future developments.