GPSolutions4 can set your PC's clock using the OEM4 GPS receiver as a precise timing reference. The timing accuracy will be better than 100 ms using this method. Here is how to do it: 1. Open up GPSolution4 and establish the communication between your PC and the OEM4 GPS receiver. 2. Open "Position Window" (View->Position Window). 3. Wait until the GPS receiver has obtained a valid position, and the clock status is set to "FINESTEERING" as reported in the header of any ASCII output message. (i.e., LOG BESTPOS in the Command Console window, and wait for field #11 of the header to switch to "FINESTEERING", which will occur within five minutes of a cold start of the GPS receiver) 3. Click the right mouse on the "Position Windows" and small menu pops up. 4. Select "Set PC Clock". 5. Done.