Forked this besutiful list from @barbeau repo (https://github.com/barbeau/awesome-gnss)

• Android apps (open-source)
• iOS apps (open-source)
• Desktop tools (open-source)
• Desktop tools (proprietary)
• Web tools (proprietary)
• Libraries and interfaces
• Data
• Social media
• Blogs
• Wikis
• Videos
• Articles
• Academic peer-reviewed publications
• Books
• Lists

• GPSTest (Google Play, F-Droid, Source code) - Supports dual-frequency GNSS for GPS, GLONASS, QZSS, BeiDou/COMPASS, Galileo, IRNSS, as well as various SBAS systems. Supports measuring accuracy using a ground truth location and file logging for NMEA, raw measurements, navigation messages, and location data. Logs are compatible with Google's GPS Measurement Tools suite to visualize data.
• GNSSLogger (Source code) - Log raw measurements for visualization in Google's GPS Measurement Tools suite. No longer maintained by Google. A proprietary Google fork of the project can be downloaded from Google Play here.
• GNSS Compare (Google Play, Documentation, Source code) - Supporting calculating positions from raw measurements for GPS and Galileo. Beta support for dual-frequency.
• RTKGPS+ (Google Play) - Android frontend of RTKLIB.
• Sat Stat (F-Droid, Source code) - Android Location, Sensor and Radio Network Status.

• Open GPX Tracker (App Store, Source code) - Open source GPX tracker app written in Swift.
• Overland-iOS (App Store, Source code) - An experiment at gathering data from an iPhone to test the Core Location API and its various settings.

• Android GNSS Logger to RINEX converter (Source code) - A Python script that converts raw measurements in the CSV format supported by GnssLogger and GPSTest to the RINEX format.
• Anubis (Download) - Quality checks for GNSS data in RINEX2/3 format. Basic version is free and open-source, Pro and Real-time features available at a cost.
• BKG Ntrip Client (BNC) (Download) - BNC is an open-source multi-stream client designed for a variety of real-time GNSS applications. It was primarily designed for receiving data streams from any Ntrip supporting Broadcaster. It can compute a real-time Precise Point Positioning (PPP) solution from RTCM streams or RINEX files. See related open-source tools for Ntrip on this page.
• EGNOS Toolkit (Download, Source code)- A set of tools to work with Satellite-Based Augmentation Systems (SBAS), specially EGNOS. Support Linux.
• FGI-GSRx (Source code) - An open-source software receiver in MATLAB used to develop, test and validate novel receiver processing algorithms for robust, resilient and precise Position, Navigation and Timing (PNT). Developed by the Finnish Geospatial Research Institute (FGI).
• Ginan (Source code) - A processing package being developed by Geoscience Australia to provide real-time corrections to positioning data from the Global Navigation Satellite System (GNSS) constellations.
• goGPS project - An open-source software package designed to improve the positioning accuracy of low-cost GPS devices by relative positioning. There are several versions, including goGPS_Java and goGPS_MATLAB.
• Google's GPS Measurement Tools suite (Download, Source code) - Desktop companion app for GNSSLogger to visualize and analyze raw measurements. Supports Windows, Mac, and Linux.
• GPSPACE - Fortran script for Precise Point Positioning.
• GNSS-SDR (Download, Source code) - An open source GNSS software defined receiver. Supports Linux, Mac, and Windows.
• GraphGNSSLib (Source code) - An Open-source Package for GNSS Positioning and Real-time Kinematic Using Factor Graph Optimization.
• GPSTk (Download, Source code) - C++ open source library and a suite of applications for GPS processing problems.
• RNXCMP (Download) - Open source software for Hatanaka compression/restoration of RINEX observation files.
• RTKLIB (Download, Source code) - An Open Source Program Package for GNSS Positioning. Has a companion Android app RTKGPS+. Supports Windows.

• GFZRNX - RINEX GNSS Data Conversion and Manipulation Toolbox Download - Supports various translation, conversion, and quality check operations on RINEX data.
• gLAB Lab (Download) - Performs precise modeling of GNSS observables (pseudorange and carrier phase) at the centimetre level, allowing both standalone GPS positioning and PPP. Supports RINEX-3.00, SP3, ANTEX and SINEX, as well as GPS, Galileo, and GLONASS. Developed under an European Space Agency (ESA) contract by the Universitat Politecnica de Catalunya (UPC). Free to download.
• SNIP (WebPage), SNIP is an NTRIP Caster that is easy to use for most aplications.
• teqc (Download) - Translation, editing, and quality check of GNSS data in native and in RINEX/BINEX formats. Free to download. End-of-life as of February 25, 2019.

• GNSS-Radar - GNSS coverage simulator over time for any given location.
• Jason Positioning-as-a-Service - Upload GNSS data (e.g., RINEX, u-blox files, GNSS logger files) and process it using Post-processing Kinematic (PPK) strategy. Automatically picks a nearby reference receiver. Currently free in beta, but will become a paid service with a free tier for evaluation and low-volume usage.
• HowToCreate GPS/GNSS log file parser - Upload gnss_log output from GPSTest or Google's GnssLogger, or a CSV file containing the same columns. The tool processes the data, and applies a static Kalman filter to refine the position of the GNSS device, much better than basic averaging, since it can use the estimated accuracy for weighting.

• earth-gravitational-model - A lightweight port of the GeoTools EarthGravitationalModel as a Java library to convert WGS84 (GNSS) altitude to EGM84 (height above mean sea level). Can be used on Android without requiring the entire GeoTools suite.
• giulioscattolin/google-gnss-logger - A Java library that facilitates reading, writing and processing of sensor events and raw GNSS measurements encoded according to the Google's GNSS Logger application format.
• ntripstreams - Python interface to transfer GNSS and related data between GNSS instruments, Ntrip caster and users using the Ntrip protocol.
• gps_pvt - An Open Source Program Package for GNSS Positioning which is runnable and controllable via Ruby. RINEX ver.2/3, SP3, ANTEX, and u-blox UBX parsers are included.
• rust-rinex - Rust package to parse and produce RINEX files
• rust-sinex - Rust package to parse SINEX files

• Android smartphones high accuracy GNSS datasets by Google - Datasets collected from multiple Android phones, accompanied with high accuracy ground truth. This dataset has 39 traces collected from Pixel 4, Pixel 4 XL, and Xiaomi Mi8. They contain CN0, carrier phase, Doppler rate, satellite transmit time, signal arrival time, and other raw GNSS measurements of L1, L5 channels from GPS, Galileo, GLONASS, Beidou, and QZSS. Precise location ground truth files collected using NovAtel SPAN system are provided. Part of the Google Smartphone Decimeter Challenge at ION GNSS+ 2021.
• GPSTest Device Database - A list of device capabilities (e.g., supported GNSS constellations and carrier frequencies) crowd-sourced from users of the GPSTest Android app.

• EUSPA - EU Agency for the Space Programme.
• GNSS Status - GNSS satellites updated status.
• IGS - International GNSS Service.

• BlackDotGNSS - Technical discussions related to GNSS data processing.
• rtklibexplorer - Using RTKLIB for precise positioning with low-cost GNSS receivers.

• Navipedia by ESA - An online reference for GNSS systems and data processing.
• How to Build a DIY GNSS Reference Station from Sparkfun.

• SPECIAL TOPICS 2 - GPS from Michel van Biezen Channel. This contains easy to understand basic explanation for GPS positioning algorithm and signal analysis.
• How to get one-meter location-accuracy from Android devices (Google I/O '18) by Google - Discussion of calculating position from raw GNSS measurements, including carrier phase measurements, as well as Wi-Fi RTT.

• Android - Raw GNSS Measurements by Google - Lists Android devices that support raw GNSS measurements as well as documentation for GNSSLogger and Google's GPS Measurement Tools suite.
• Dual-frequency GNSS on Android devices by Sean Barbeau - Discussion of dual-frequency GNSS support on Android, including screenshots showing device support for dual-frequency in GPSTest.
• tl;dr — Dual-frequency GNSS on Android — Table of devices by Sean Barbeau - Table summarizing the above article.
• GNSS Analysis Tools from Google by Inside GNSS - Discussion of Google's GPS Measurement Tools suite.
• Improving urban GPS accuracy for your app by Frank van Diggelen and Jennifer Wang at Google - Description of Google's improvements to the fused location provider using 3D mapping aided corrections.
• Measuring GNSS Accuracy on Android devices by Sean Barbeau - Discussion of estimated and actual accuracy on Android, including the feature in GPSTest to measure actual accuracy.
• SAR and GNSS, monitoring Earth from space by Toni M. del Hoyo in Worldsensing's Tech Blog - Overview on Global Navigation Satellite systems and on Synthetic Aperture Radar
• Using GNSS Raw Measurements on Android Devices by GSA GNSS Raw Measurements Task Force - Technical discussion of how to determine a device's position based on raw pseudorange measurements provided via Android APIs.

• Wanninger and Anja Heßelbarth1. "GNSS code and carrier phase observations of a Huawei P30 smartphone: quality assessment and centimeter-accurate positioning", GPS Solutions, 24:64, March 2020.
• Jacek Paziewski, Marco Fortunato, Augusto Mazzoni, Robert Odolinski. "An analysis of multi-GNSS observations tracked by recent Android smartphones and smartphone-only relative positioning results", Measurement, Volume 175, 2021, https://doi.org/10.1016/j.measurement.2021.109162.
• Ng, H-F, Zhang, G, Luo, Y, Hsu, L-T. "Urban positioning: 3D mapping-aided GNSS using dual-frequency pseudorange measurements from smartphones." NAVIGATION. 2021; 68: 727– 749. https://doi.org/10.1002/navi.448
• Yong et al. - "Instantaneous, Dual-Frequency, Multi-GNSS Precise RTK Positioning Using Google Pixel 4 and Samsung Galaxy S20 Smartphones for Zero and Short Baselines", Sensors 2021, 21(24), 8318; https://doi.org/10.3390/s21248318.
• Li et al. - "Ambiguity resolution for smartphone GNSS precise positioning: effect factors and performance", Journal of Geodesy 96, 63 (2022). https://doi.org/10.1007/s00190-022-01652-7.

• Introduction to GNSS by Hexagon | NovAtel - Detailed introduction to many major concepts around positioning with a heavy focus on GNSS.
• Global Navigation Satellite Systems - Education Curriculum by United Nations Office for Outer Space Affairs. Good glossary of GNSS terms.
• GNSS Data Processing books by UPC/gAGE - Theory and exercises to learn GNSS data processing (e.g., range modelling, navigation equations, Kalman filter)

• Upcoming satellite launches by GPS World
• Galileo
  • Supported devices (official)
  • Real-time status (official)
• Positioning Australia
  • Global Navigation Satellite System Data Centre (official)
• QZSS
  • Supported devices (official)
• WAAS
  • Real-time status (official)

• NTRIP Client PC based, offered by Lefebure Design, LLC.
• Lefebure NTRIP Client free android product, offered by Lefebure Design.
• RTKLIB (already discussed above)& the [RTKEXPLORER] (https://rtkexplorer.com/) the Source Code.
• BKG Ntrip Client (BNC) RTKexplorer has been developped from RTKLIB, where some problems with the RTKLIB connection logic have been solved.
• NtripClient, Ntrip Version 2.0 Command Line Client free product offered by BKG offered by Dirk Stoecker Alberding GmbH. C source code avialable here(http://igs.bkg.bund.de/root_ftp/NTRIP/software/ntripclient.zip) & here(https://software.rtcm-ntrip.org/).
• GnssSurfer (http://217.9.43.196/Download/GnssSurferV1.10.zip)
• SXBlue RTN (https://sxbluegps.com/for-downloads-please-browse-individual-products/)

Added the following from @mvarga1989 repo (https://github.com/mvarga1989/Awesome_GNSSreceivers)

Please keep in mind that the links provided may not be the official website of the company and they may have changed since the last update.