By Stephen Mackey, Hadi Wassaf, Karen Van Dyke, Christopher Hegarty, Karl Shallberg, John Flake and Terence Johnson.
The Adjacent Band Compatibility Assessment evaluated the adjacent radiofrequency band power levels that can be tolerated by GPS and GNSS receivers, to advance the U.S. Department of Transportation’s understanding of the extent to which such power levels impact devices used for transportation safety purposes, among other applications. The paper describes the testing approach and data analysis used to develop interference tolerance masks (ITMs) based on a 1-dB carrier-to-noise-ratio (CNR) degradation. DOT and other participants tested 80 GPS/GNSS receivers in an anechoic chamber. Four types of testing were conducted which involved a linearity test, 1-MHz Bandpass Noise, 10-MHz Long Term Evolution (LTE), and effects of third order intermodulation.
This paper also presents the resulting ITMs and puts forward a recommendation for the bounding ITM for each GPS/GNSS receiver category. Given a particular use case scenario, the significance of these bounding ITMs is that they provide information that is necessary for the downstream analysis to determine the maximum Effective Isotropic Radiated Power (EIRP) that can be tolerated in the adjacent radiofrequency bands on a per category basis. The paper discusses acquisition results as they relate to the 1-dB CNR degradation limit, and a cross comparison for some of the receiver results between radiated and conducted tests incorporating the appropriate antenna characterization data.
Presented at ION ITM, January 2017.