Abstract: | All smartphones today have a GNSS receiver on board and most smartphones also have an LTE modem. The LTE Standard [1] regulates bandwidths, power, bands and other parameters of the LTE signal. However, there are many different LTE bands, and some of the bands have the second harmonic of their frequency range very close to the GPS L1 band. For instance, the uplink channels of LTE Band 13 and 14 have the second harmonic of their central frequencies at 1564 MHz and 1586 MHz, respectively. Considering the maximum bandwidth of the channels, the transmitted signal may be located just a few megahertz away from the GPS L1 frequency band. This close proximity creates interference conditions (“LTE jamming” here and below) for a GNSS receiver every time an LTE modem transmits something. The maximum allowed transmission power is limited by 23 dBm. The LTE jamming power, which a GNSS receiver gets at its input, is much lower than that and determined by the antenna isolation and nonlinearity of the LTE transmitter power amplifier (PA), which creates the second harmonic of the signal. The absolute power of the LTE signal at the GNSS receiver input port significantly depends on these factors, which are specific for any modem and hardware design, but none of these parameters are ideal. In addition, the paper shows that, in some configurations, the LTE jammer may be located too close to the GPS L1 band to be rejected by a SAW filter. The resulting jamming can seriously degrade the performance of a GNSS receiver, creating position outliers and even loss of position fix. This paper shows the impact of the second harmonic of the LTE signal on the GPS receiver performance and gives recommendations to receiver designers to address that. The significance of this work lies in the determination of the GPS receiver SNR loss as a function of the LTE jamming parameters at the input. Importantly, this work also provides recommendations to GNSS receiver designers about selecting certain receiver design parameters. Note, however, that LTE jamming can adversely affect constellations other than the GPS system that is studied in this work. |
Published in: |
Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado |
Pages: | 3915 - 3924 |
Cite this article: | Kuznetsov, Dmitry, "Characterization of LTE Jamming and its Impact on GPS Receivers," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 3915-3924. https://doi.org/10.33012/2022.18574 |
Full Paper: |
ION Members/Non-Members: 1 Download Credit
Sign In |