I have two/three related questions about the code measurements given in the RINEX observation file. 1) Are the reported pseudoranges already corrected for the receiver's clock bias? 2) Are they corrected for each satellite's clock bias? 3) Is it reasonable to estimate a signal's travel time by dividing the reported psuedorange by the speed of light? I'm trying to develop my own MATLAB code to calculate a receiver's position using data from RINEX observation and navigation files, but I'm getting position errors upwards of +/-25m (RMS).