We have developed in-house, original software for real-time GNSS processing called GNSS-WARP. We are using the software in our real-time related research and activities, as well as to develop Precise Point Positioning (PPP) algorithms.
The GNSS-WARP software is implemented in Matlab, but is not stand-alone software. For real-time processing it requires BKG Ntrip Client (BNC) software provided by BKG to handle Networked Transport of RTCM via Internet Protocol (NTRIP) for streaming GNSS and differential correction data over the Internet (Weber et al., 2005). The observables from the GNSS receiver and broadcast messages are decoded from RTCM 3.x format and IGS Real-Time Service (RTS) correction streams are decoded from a RTCM state space representation (SSR) standard (Wübbena et al., 2005).
The GNSS-WARP is also capable of processing data in classical post-processing mode (using .sp3 and .clk files), as well as to operate in simulated real-time mode (reliably reflecting real-time processing) using RTS products recorded with BNC in ASCII files.
The software is highly configurable, capable of processing static and kinematic data. It supports GPS and GLONASS, while other systems (Galileo and Beidou) are under implementation/validation.
More details about the software and some real-time results can be found in the following paper:
Hadas T (2015) GNSS-Warp Software for Real-Time Precise Point Positioning. Artificial Satellites 50(2):59-76 (https://www.degruyter.com/view/j/arsa.2015.50.issue-2/arsa-2015-0005/arsa-2015-0005.xml)
References: Weber, G., Dettmering, D., and Gebhard, H. (2005). Networked transport of RTCM via Internet Protocol (NTRIP), IAG Symposium, 128, 60–64.  Wübbena, G., Schmitz, M., and Bagge, A. (2005). PPP–RTK: precise point positioning using state-space representation in RTK networks, Proceedings of 24th International Technical Meeting of The Satellite Division of the Institute of Navigation, Institute of Navigation, Long Beach, CA, 2584–2594.