Navic is Indian Navigation Satellite System. It has 2 open-service signals. While L5 signal shares the same frequency, as GPS L5 signal, S Signal has extremely different frequency about 2.5 GHz. JAVAD GNSS TRE-3S receiver has additional RF part that is able to receive it. In spite of noise from Wi-Fi (which shares the same frequency in Europe and most of other regions) TRE-3S successfully tracks it in center of Moscow (Russia). Graphs show Signal-to-noise ratio (C/N0) and range-minus-phase combination. On the graphs, S signal is places on C/A place (red color).
Currently, in addition to TRE-3S receiver, TR-3S receiver also capable of S signal tracking.