Added SiRF-Support to RTKLIB

In my last post I wrote about the opportunities of GNSS receivers based on the low cost SiRFstar chipset in comparison to the well known and famous U-Blox chipset.
It seemed hopeless to wait for Mr. Illarionov to update his six year old code base and also Mr. Everett seemed to have other priorities regarding his project.
So I decided to fork Mr. Everett’s RTKLIB source repository to reintegrate Mr. Illarionov’s code for SiRFstar based receivers and to enable the community to make use of it.
Although I am not a C programmer I managed to improve the code to get a astonishing performance comparable to the U-Blox reference.
In the following 12-hour datasets, source of Solution 1 is SiRF IV, source of soulution 2 is U-Blox M8T, both placed next to each other on a backing tray. As you can see, sub-centimeter precision accuracy is possible. Ground Track remains in a 6cm² area over the whole time. The Ground station I recently built was used as reference for all measurements.
https://github.com/SJuhl75/RTKLIB/tree/SiRF