1. Download and install the PC utilities from http://www.novatel.com/support/fwswupdates.htm (you want to get the “PC Utilities (OEMV/OEM4/Superstar II)” or at least one of these that has the convert4 program (the direct link to the full install zip is http://www.novatel.com/Documents/Downloads/CDU_WithDotNet_Inst_3.3.0.3.2113.zip).
2. Load up the convert4 utility program
3. Pick your source (I used sdr-ALL.dat) and your destination (I am using sdr-imu.bin as my output)
4. Check the selected data items, and just pick the RAWIMU data (this is the majority of the data)

and