Power Characterization for L1 and L5 Transmissions

Abstract

This article aims to characterize the GPS L5 signal power, and how it differs from the GPS L1 C/A signal power. This was done in order to determine if the GPS L5 signal would be advantageous to use indoors. The specifications of the GPS L5 signals show a 3.6 dB increase from the specifi- cations for legacy L1 C/A signals. To verify the increased transmitted power an estimate of the satellite transmit antenna pattern was found for two of the Block IIF satellites with high enough passes over Boulder, Colorado, by subtracting the receiver antenna pattern. The L5 signal showed an average transmitted higher power of 2.7-3.1 dB which is slightly less than expected, but still close. A second experiment was set up to measure the impact of the reception antenna pattern. Four different antennas were used to collect data and compare the measured signal power to expected signal power for GPS L5. Two of the antennas show lower than expected signal powers for L5, especially for high elevation angles. As mentioned above this research effort took place in order to determine whether the GPS L5 signal would be preferable to use indoors. An assisted technique was used to detect the L1 and L5 signals inside the engineering building of University of Colorado. The results showed a mean of 3.5 dB higher power for GPS L5 compared to GPS L1 which shows that GPS L5 would be a good choice for indoor GPS applications.