GPS Location Spoofing and FM Broadcast Intrusion Using Software-Defined Radio

Fm Transceiver

An example of a basic application of SDR is to build a radio station receiver. Radio stations in Singapore broadcast islandwide with frequency modulation (FM) which essentially modulate information by changing the carrier frequency. Hence, radio stations modulate audio information into the given frequency and transmit the radio waves island wide. On the receiving end, end users use a FM radio turner to demodulate the radio waves and play back the audio information.

The FM transceiver is coded in GNURadio (GNURadio) as shown in Figure 1. GNURadio provides a huge cache of signal processing blocks to implement real world software radio systems. The SDR can therefore listens to FM transmission. It can also be used to broadcast FM signals to nearby receivers effectively hijacking the broadcast from the official radio stations and replacing the official broadcast with spoofed transmission. All it takes is to for the SDR to transmit the spoofed audio file to the nearby FM radios. The nearby radio tuners will receive the spoofed broadcast since the received SDR’s signal strength is stronger than the official broadcast. As the SDR has limited signal power, it is not feasible to hijack FM broadcast islandwide but given enough SDR power, a localized area’s FM broadcast can be hijacked and spoofed.