One new feature of the reports TNW.4S that may have snuck by your radar is support for GLONASS,
GLONASS, an acronym for Globalnaya navigatsionnaya sputnikovaya sistema or Global Navigation Satellite System, is a radio-based satellite navigation system operated for the Russian government by the Russian Space Forces. It is an alternative and complement to the United States’ Global Positioning System (GPS). [W]GLONASS navigation definitions for latitude and longitude are 4.46 – 7.38 m. In comparison, GPS navigation definitions are 2.00 – 8.76 m. This indicates that GPS is slightly more accurate; however, on northern latitudes, GLONASS’ accuracy is better than GPS due to the orbital position of the satellites.
Using both GLONASS and GPS satellites together provides improved coverage and gives a very fast fix time due to over 50 satellites being available. GLONASS/GPS navigation definitions are 2.37 – 4.65 m.