## 1 Introduction  
GNSSs are considered a crucial element in enabling higher levels of autonomy [1], but the current limitations associated with the connection integrity of these systems impair its importance in the decision-making systems of autonomous vehicles (AVs) [2]. The limitations can be multipath and non-line-of-sight signals, highly dynamic environments, and susceptibility for intentional or accidental interference, such as jamming and spoofing [3; 4; 5]. These limit the overall performance of current driving automation and must be overcome to guarantee the success of AVs. Systems with higher degrees of automated driving will eventually require instantaneous, centimeter accurate positioning [6]. Software-defined antennas (SDAs) are being explored as platforms to support next-generation wireless capability [7; 8; 9]. The benefit of such antennas can be leveraged to improve the quality of GNSS services in severely degraded environments [10]. Smart adaptive antennas that track GNSS satellites have been shown to help alleviate both situations [11]. However, their development presents certain challenges. SDAs are composed of the antenna array and the control unit, both requiring extensive development and testing. Antenna characterization is usually performed by antenna pattern measurementsin an anechoic chamber [9; 12], requiring a platform to control the phases introduced to each channel. On the control unit side of the system, complex control algorithms must be developed to maximize the benefits of SDAs for GNSSs [13]. These algorithms handle interference mitigation and signal enhancement, among other tasks. Their development requires extensive testing in anechoic chambers as well as \"real world\" tests [14]. More factors like array size, phase, and delay calibration between elements, and overall cost, which increases with the number of elements, impose technical challenges for the deployment of such solutions in the mass market sector. Therefore, commercially available systems usually utilize 2-3 elements and employ only interference mitigation rejection [15; 16]. When developing antenna arrays and beamforming algorithms, we can resort to a multitude of methods. With simulations, we can quickly and inexpensively validate the proposals. However, real-world validation is extremely valuable. Alternatively, or together with simulations, we can develop a dedicated system to test the proposal. With these dedicated systems, optimal performance can be achieved. Nevertheless, it is an expensive and time-consuming process, as each system is custom-made. Resorting to radio frequency system on chips (RFSoCs) can alleviate this. RFSoCs integrate hardened high-speed data converters with already established FPGA and microprocessor architectures [17]. This unlocks highly versatile and adaptable systems for quick development and real-world testing with much lower costs. This paper presents a receiver-independent implementation of a software-defined platform with the use of RFSoC technology, aiming to facilitate its integration with existing automotive receivers. This system is intended to be used as the backbone for the development of antenna arrays and beamforming algorithms. Given its flexibility, it is not necessary to develop new hardware between development iterations or even for different systems, as only the software layer needs to be modified. Consequently, it is possible to expedite the development stage before producing dedicated solutions for industrial applications. Previous works we have found in our research have not explored this. The proposal of an antenna array for GNSS applications is not in the scope of this paper. The main contribution of this paper is the development of a platform for standalone solutions that can be integrated into existing receivers as if it were a traditional single antenna, i.e., the output of the array and FPGA is a single signal fed to the receiver. This paper continues with a summary of related works in the following section.