Discussion about calibration of the local oscillator frequency of the bullseye LNB
https://github.com/g4eml/Bullseye-Calibrator

Map showing radio sondes carried on weather balloons.

Peregrine is a fast and flexible open-source software GNSS receiver. It can be used as a standalone application to post-process GNSS data all the way to PVT solutions or as from within IPython as a toolkit for GNSS data exploration.

Peregrine is written in Python for flexibility and ease of development and uses the libswiftnav C library for speed.

Full documentation available online at http://docs.swift-nav.com/peregrine

Found via https://github.com/odrisci/gnss-sdr, a fork of GNSS-SDR implementing code-less tracking for Galileo E1 PRS signals, which in turn was found in "Codeless Code Tracking of BOC Signals" by Cillian O’Driscoll, James T. Curran; Proceedings of the 29th International Technical Meeting of the ION Satellite Division, ION GNSS+ 2016, Portland, Oregon, September 12-16, 2016, pp. 497-508.

You supply an antenna and a complex (I/Q) mixer to convert the radio spectrum to a low IF. Then send that IF to your computer using the sound card, Ethernet or USB. The Quisk software will read the I/Q data, tune it, filter it, demodulate it, and send the audio to headphones or speakers. Quisk has a microphone input and a key input so it can operate as a complete transceiver.

The FGI-GSRx software receiver has been extensively used as a research platform for the last one decade in different national and international Research and Development (R&D) projects to develop, test and validate novel receiver processing algorithms for robust, resilient and precise Position, Navigation and Timing (PNT). At present, the FGI-GSRx can process GNSS signals from multiple constellations, including GPS, Galileo, BeiDou, GLONASS, and NavIC. The software receiver is intended to process raw Intermediate Frequency (IF) signals in post-processing. The processing chain of the software receiver consists of GNSS signal acquisition, code and carrier tracking, decoding the navigation message, pseudorange estimation, and Position, Velocity, and Timing (PVT) estimation. The software architecture is built in such a way that any new algorithm can be developed and tested at any stage in the receiver processing chain without requiring significant changes to the original codes.

Kalibrate, or kal, can scan for GSM base stations in a given frequency band and can use those GSM base stations to calculate the local oscillator frequency offset.

An experimental asynchronous SDR runtime for heterogeneous architectures that is:
- Extensible: custom buffers (supporting accelerators like GPUs and FPGAs) and custom schedulers (optimized for your application).
- Asynchronous: solving long-standing issues around IO, blocking, and timers.
- Portable: Linux, Windows, Mac, WASM, Android, and prime support for embedded platforms through a REST API and web-based GUIs.
- Fast: SDR go brrr!
Found on https://www.rtl-sdr.com/futuresdr-an-async-sdr-framework-implemented-in-rust/

SDR Makerspace is an initiative of the European Space Agency and Libre Space Foundation bringing together makers, open-source hackers, radio amateurs, researchers, from all over Greece and provide funding, resources, and a passionate community tackling together challenges in using Software Defined Radio for space communications, opening up space communications development to a wide variety of people, organizations and companies.

Gqrx is an open source software defined radio receiver (SDR) powered by the GNU Radio and the Qt graphical toolkit.

Recently "Lama Bleu" has been working on a custom firmware image for the PlutoSDR. Installing custom firmware allows you to load up a pre-configured Linux system which already has a bunch of useful software installed. He writes that his version is not designed to have a nice GUI, but rather focuses on scripting and data acquisition software.