The Android Framework provides access to raw GNSS measurements on several Android devices (Android 7 or higher is needed).

Exploring precision GPS/GNSS with RTKLIB open source software and low-cost u-blox GPS receivers.
This particular post links to the announcement of the u-blox ZED-F9P high precision GNSS module
https://www.u-blox.com/en/product/zed-f9p-module
According to https://forum.u-blox.com/index.php/18878/when-can-i-get-a-zed-f9p
"I contacted u-blox and they said that the evaluation kits will be available at the end of Nov 2018."

The uBlox LEA-6T supports precision GPS timing for demanding positioning applications such as basestations. It features a time mode function whereby the GPS receiver assumes a stationary 3D position, whether programmed manually or determined by an initial self-survey. Stationary operation enables GPS timing with only one visible satellite and eliminates timing errors which otherwise result in positioning errors. An accuracy of up to 15 ns is achievable by using the quantization error information to compensate the granularity of the time pulse. A built-in time mark and counter unit provide precise time measurement of external event inputs

GNSS receiver based on ublox MAX-M8Q for the Raspberry π. Other interesting parts such as antennas, filtered pre-amplifiers etc. are available too.

GNSS signal processing functions written in C
       Code generations
       Signal acquisition / tracking
       Decoding navigation messages
       Pseudo-range / carrier phase mesurements
   GUI application (AP) written in C++/CLI
   Visualization of GNSS signal processing in real-time
   Real-time positioning with RTKLIB (http://www.rtklib.com/)
   Observation data can be outputted in RINEX or RTCM format
   Support following signals (tracking and decoding navigation message)
       GPS L1CA
       GLONASS G1
       Galileo E1B
       BeiDou B1I
       QZSS L1CA/SAIF/LEX
       SBAS L1
   Support following front-ends for real-time positioning
       NSL Stereo http://www.nsl.eu.com/primo.html
       SiGe GN3S sampler v2/v3 https://www.sparkfun.com/products/10981
       Nuand BladeRF http://nuand.com/
       RTL-SDR http://sdr.osmocom.org/trac/wiki/rtl-sdr
   Support RF binary file for post processing

GNSS receiver hardware (IP cores) with LEON or RISC-V processors.

Just what it says. Written in c and GPL licensed.

Information about the status of the Galileo satellite navigation system.

10 November 2014

ESA’s fifth Galileo navigation satellite, one of two left in the wrong orbit this summer, will make a series of manoeuvres this month as a prelude to its health being confirmed.