UNB Physics Seminar Series-FR

Event date(s): March 21, 2023
Time(s): 01:15 PM - 02:15 PM
Category: Fredericton
Location: Fredericton

UNB Physics Department Seminar

When: Thursday, March 21, 1:15 pm

Location: Toole Hall, Room 3

Speaker: Nancy Abraham

Title: Inter-Satellite GPS Interference: Observation and Model

Abstract: One of the reasons Global Positioning System (GPS) interference can occur is that signals transmitted by different satellites bearing similar Doppler shifts interfere with each other due to their Course-Acquisition (C/A) codes cross-correlating. C/A code, a Pseudo random noise (PRN) sequence transmitted on L1 frequency, modulates each satellite signal's phase with a distinct sequence. With the development of Canadian High Arctic Network (CHAIN) receivers that sample GNSS signals at a high rate, it has become possible to identify and characterize inter-satellite interference. The variations, often rendering a beat frequency pattern, caused by interference can be observed in the carrier phase and the amplitude of the signals. Spectrograms of the events show peak frequencies that match the Doppler shift difference between the satellite signals and are present in each interfering signal. A model demonstrating the beat frequency pattern using the contribution of factors such as C/A cross-correlation and relative Doppler shift has been showcased, the results of which have been validated using observational data. The results can help predict inter-satellite interference under certain conditions and provide signatures for efficient filtering of such events from scintillation and multipath studies.

Building: Toole Hall

Room Number: 3