Determining the correct Ephemeris File to Download from IGS

How to determine the correct Ephemeris File to download from IGS:

  1. First look at the OPUS report from the GPS unit. Find the highlighted info in Figure 1:


Figure 1


  1. Go to the IGS website: Click on the GPS or GLONASS link as shown in Figure 2:


Figure 2

  1. For this example, I chose GPS. Click on the link with the number that corresponds to the first 4 digits of the ephemeris that was in the OPUS file as shown in Figure 3:


Figure 3

  1. Click on the link with the SP3 file that has the exact number from the OPUS solution as shown in Figure 4:


Figure 4

  1. Use a file extractor to unzip this file, such as: Windows, 7Zip, etc.

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