I am currently trying to understand the best way to use the available information in RINEX navigation files for GPS and GLONASS satellites. My main goal currently is to calculate the position at epoch for the distributed navigation files. I understand that RINEX navigation files contain, in addition to orbital parameters (for GPS) or Cartesian coordinates (for GLONASS), additional parameters to calculate the orbital parameters or Cartesian coordinates at future/past time points (e.g., for the case of GPS navigation files: inclination rate; amplitude of sine and cosine corrections for inclination, orbital radius and latitude argument; the mean motion difference from computed value, and others).
However, if I just aim to extract the position at epoch, is it safe to ignore such additional parameters and just either extract directly the Cartesian coordinates for GLONASS satellites, or to calculate them from the osculating orbital elements directly derived from the data provided in the navigation file for GPS satellites?
Additionally, if just calculating the position at epoch, is there any need to apply clock corrections with the supplied clock bias, clock drift and clock drift rate corrections?
Thanks a lot in advance.
Searching other RINEX-related questions, I found TLE and RINEX gps differences and Elevation and Azimuth of satellite in different location, but both seem to be focused on the difference between elements obtained from TLE and RINEX files, and do not contain confirmation of my original questions.