Time: November 10, 2015

Location: Chengdu Shuangliu Airport

Personnel: relevant personnel of Southwest Air Traffic Control Bureau of civil aviation, Sichuan Radio Monitoring Station and Chengdu lattice

Background:

Southwest Air Traffic Control Department of civil aviation received a complaint that GPS interference was found near the second runway of Chengdu Shuangliu Airport. The GPS signal is lost when the plane lands below several hundred meters, which seriously affects the normal operation of the flight. However, the normal ground monitoring methods fail to find the interference signal, which is very urgent. Subsequently, Southwest Air Traffic Control Bureau and Sichuan Radio Monitoring Station informed our company to immediately arrange air monitoring and direction finding system to assist in interference investigation.

Interference elimination process:

After receiving the notice, our company rushed to the scene quickly, and selected a higher position (about 2km from the second runway) in the complaint area to launch the UAV.

The UAV is set to scan the GPs working frequency band from 1565mhz to 1585mhz. When the UAV is lifted to 50m, it receives the interference signal. We find that this is a broadband signal, and it works in sweep mode.

Our company's staff immediately command the direction finding of UAV. Horizontal polarization and vertical polarization are used successively, and the direction finding results are 43 degrees and 44 degrees respectively, both pointing to the direction of the large-scale road, and the intensity is only less than 40 dB higher than the bottom impetuosity.

According to this, we infer that the signal is not far away. We use the company's dzh-100 handheld monitoring receiver, and set the frequency to 1574.4mhz, as the UAV points forward.

After a short time, according to the intensity comparison, it is determined that the signal near a garage is the strongest, and it is found that the signal is seriously spurious after approaching the signal, which is not like a normal transmitting device.

Due to the complex environment of the garage, we used dzr-100 concealed equipment to enter the factory to check and find that the signal is very strong near a garage of the garage, and the iron door of the garage is locked tightly, there are a large number of luxury vehicles in the garage. It can be concluded that this interference is a GPS jammer. In order to prevent the stolen vehicle's positioning system from receiving the normal GPS signal, it sends out the vehicle's position.

Finally, we will report the investigation to Sichuan Radio Monitoring Station and Southwest Air Traffic Control Bureau, and the relevant departments will coordinate with the public security department to deal with it.