Hello Dominic! GPS signals include ranging signals, used to measure the distance to the satellite, and navigation messages. The navigation messages include ephemeris data, used to calculate the position of the satellite in orbit, and information about the time and status of the satellite constellation. According to the band division, GPS signals are L1-L5 respectively. Usually we say interference can only interfere with three of the civilian frequency band. The other two military signal bands can not be interfered. So, if you use GPS jammer, you can interfere with all civil frequency bands