LEO satellite delay and Doppler simulation and adjusted NR_UE time sync
- Added rfsim channel models SAT_LEO_TRANS and SAT_LEO_REGEN to simulate time-variant delay and Doppler for circular satellite orbit. Delay and Doppler computation is done as in Matlab function dopplerShiftCircularOrbit: https://de.mathworks.com/help/satcom/ref/dopplershiftcircularorbit.html
- Improved NR_UE time sync by adding PI comtroller
- Added Rel17 NTN parameter ta_CommonDrift_r17 and use it as initial value to compensate time drift starting during initial sync
- Add autonomous TA update to NR_UE based on the measured DL drift to keep UL sync (this needs to be replaced by standard compliant algorithm once SIB19 is implemented with continuously updated contents)