On April 18, 2018, the radio management department of Zhanjiang City, Guangdong Province successfully completed the investigation and handling of an interference event of civil aviation air GPS navigation system. The air radio monitoring system and hand-held radio monitoring equipment produced by our company played an irreplaceable role in the investigation and handling process.

I. background

On April 13, 2018, Zhanjiang Radio Management Office received a complaint of interference from Zhanjiang Airport, saying that during the regular airport calibration, the calibration aircraft crew found that the GPS navigation system at two locations along the airport channel, i.e. 2.2 nautical miles and 2.4 nautical miles, was interfered, which affected the GPS positioning of the calibration aircraft, and the blind landing equipment could not be used. This event will directly affect the take-off and landing safety of the aircraft flight, but also hinder the use of the blind landing equipment The calibration work is normal.

II. Routine troubleshooting

After receiving the complaint of airport interference, Zhanjiang radio management office sent technicians to monitor the ground area of the disturbed location with mobile monitoring vehicle and portable direction finding equipment, and called fixed station for monitoring at the same time, but no interference signal was found. Considering that the jamming location of the calibration aircraft is hundreds of meters above the ground, and the jamming source location is not necessarily under the ground, the technicians immediately expanded the scope of monitoring, and after several days of carpet search, no trace of the jamming signal was found.

III. troubleshooting after using air radio monitoring system

Aviation safety is urgent. In view of the continuous search of ground monitoring equipment for several days without progress, on the morning of April 17, 2018, Zhanjiang no control office invited Jiangmen radio monitoring station to take the air radio monitoring system equipped with the station to assist in finding interference. After being invited, the station then invited our company to send someone to help with the search.

In the afternoon of April 17, 2018, Jiangmen City sent station chief Zou Jingcai to take 3 technical backbones with 1 set of dzf-ac1 air radio monitoring system and 1 set of dzh-200 handheld equipment produced by our company to Zhanjiang for search. Li Sen and Meng Wenjie sent by our company also arrived at the scene on that day. Zhanjiang Economic and information bureau sent Ma Yunshui Deputy investigator to be responsible for the command and coordination of the investigation. Because the disturbed area is in the glide path clearance protection area of Zhanjiang Airport, the air radio monitoring system needs to avoid normal flights during working hours, so the time of using the system can only be limited to the take-off and landing clearance of normal civil flights, which brings great inconvenience to the search.

At 15:20 p.m. on April 18, with the approval of air traffic control, the air monitoring system lifted off in Ruiyun Lake Park (this point is the place where the correction plane is 2.4 nautical miles away from the airport and disturbed).

Flight address 1: Ruiyun Lake Park

When the monitor rises to 200-300m, it finds that the normal signal of suspected interference source will lift the whole section of bottom noise, and the sweep frequency finds that the signal will lift the whole section of bottom noise at 1550mhz-1600mhz (as shown below).

Through five direction finding at different heights, it is found that the suspicious signal direction is concentrated between 239 ° and 250 ° to the south by West (as shown in test point 1 of the general drawing).

At 16:20, at the second launch site 6 km from the first launch site, the UAV was monitored to take off, but no signal was found at the altitude of 300 meters (as shown in test point 2 of the master plan).

Flight address 2: next to Yinghao middle school

The test results of the second test point and the first test point are analyzed. The tester considers that this is a directional interference source. At the third test point, 2.5km away from the first point, there is no signal when the UAV flies to 400m height (as shown in test point 3 of the master plan).

Flight address 2: next to Yinghao middle school

The test results of the second test point and the first test point are analyzed. The tester considers that this is a directional interference source. At the third test point, 2.5km away from the first point, there is no signal when the UAV flies to 400m height (as shown in test point 3 of the master plan).

4. Approaching jamming sources on foot

According to the result of UAV monitoring and direction finding intersection positioning, the jamming source is locked in the approximate range. At 19:20, a relatively high hotel was found in this range, and the signal was also received by using the hand-held monitoring equipment on the upper floor of the hotel. The direction directly points to the direction of Xiejia village, Houhe river. This result greatly inspired everyone's spirit. Director Ma of Zhanjiang monitoring station immediately decided to use mobile monitoring vehicle and hand-held direction finding equipment to carry out coverage network collection in the ground area of the disturbed location. At the entrance of Xiejia village, the mobile monitoring vehicle and the dzh-200 handheld device receive suspected interference signals at the same time. Our company's staff use dzh-200 to first find the interference information number outside a warehouse where the iron door is closed in Xiejia village. The signal strength increases when approaching the door, and reaches the maximum when approaching the iron door of the warehouse (50dB μ V). After monitoring in other directions around and asking for clues provided by nearby villagers, the testers determined that this was the location of the interference source.

V. joint public security to seize jamming equipment

At about 20:00 p.m. on April 18, 2018, Zhanjiang monitoring station, together with public security personnel, entered the warehouse and found a radio GPS jamming device in use. After turning off the power of the device, the jamming signal disappeared. The law enforcement staff of Zhanjiang monitoring station seized the equipment. After questioning the person in charge, the warehouse is the place where the mortgaged car is stored. In order to prevent the mortgagor from finding this place through the car GPS, an jammer was installed. Zhanjiang Municipal Public Security Bureau has made interrogation record, on-site inspection and equipment seizure for the case, and the incident is waiting for further handling.