The Analysis And Solution Of Radio-frequency Interference In Civil Aviation

Transportation in civil aviation is a 3-dimenssional transmission system. With the rapid development of civil aviation, the demand of utilizing radio frequency is increased. Wireless telecommunication and navigation system are the most important part of the civil aviation transportation system. It becomes the centre part of the civil aviation transportation system. On the other hand, the electromagnetic environment becomes more and more complicated due to the development of radio, television, solid communication system, mobile communication system, radar navigation, remote controlling and surveying, radio astronomy, personal radio station and other radio station. All of these become the potential interference sources of the wireless telecommunication and navigation system.Electrical interference, generally at radio frequencies (9KHz～3000GHz), is generated inside systems, which interferes with the reception of desired signals. It has adverse effects on generating signals. It also degrades the properties of the signals, causes the system losing information, and even obstructs the transformation. Electrical interference includes same frequency interference, adjacent-channel frequency interference, external interference, intermodulation interference, obstructive interference, and other interferences.Civil aviation radio-frequency is the special frequency which is distributed by Chinese National Administration of Radio used for telecommunication, navigation, and radar in civil aviation system. The range of the frequency is broad (from high-frequency to ultrahigh-frequency). Among them, the most common interference sources are at the range of very high frequency. The main interference sources are wireless paging transmitters, super power wireless phones, radio stations at rural area, super power FM radio stations, television transmitters, industrial, engineering, medical radio transmission systems and the civil aviation system it self.It is important to prevent the radio-frequency interference occurs. It is also better to prevent it happens than spend more time to solve this problem. However, there are still some methods to deal with this problem. First of all, based on the certain circumstance, the author analyzes the characters of radio monitoring apparatus and use geographic information system establishing a data monitoring and analyzing networking system. According to the type of the data on the net, analyzes data flow and chooses proper range and method to establish a completed radio monitoring network monitoring the electromagnetic environment anytime when necessary. It is required to consider the information safety and to ensure it works properly and constantly.Secondly, it is necessary to enhance the analysis of inter-electromagnetic compatibility in order to solve the problem which is cased by the civil aviation system itself. It includes: properly designing the equipment layout, preventing the interferences caused among the equipments, and testing the electromagnetic environment inside the equipment rooms.Finally, the author states that the most efficient way to solve this problem is to establish monitoring database. By diagnosing the monitoring data and warning monitoring, comprehend the distribution of the radio signals and its variety. Detect the abnormal signals and interference immediately. There are initial collection data and statistics sample data in the monitoring database. It takes one month, three months, or even long time to obtain the initial data. The minimum sample cycle unit is second. So the quantity of data is large. The system requires a sufficient input/output capability and parallel processing ability. In addition, after a long period of monitoring, the data in the database is increased dramatically. Therefore, it requires high capacity and quality database computer system.By deeply analyzing the monitoring data, the system can provide reliable ratio of the channel used, the percentage of the utilizing frequency, and the background information about each frequency for the radio administration agency. The reports are conclusive. It can also provide technical support for designating frequency, planning the use of frequency, and coordinating the use of frequency. The basic part of the warning and monitoring system is monitoring database. It can help to find the interference sources before the interference occurs. The objective of the radio warning and monitoring system is to be positive and increase the management level. By warning and monitoring the interference, we can prevent and eliminate interference, keep the air electromagnetic into order, serve the government agency, national economy, national safety, stable society. It not only requires strong technological ability, but also requires responsibility and sensitive of politics.In conclusion, the paper based on analysis of the special radio-frequency interference and radio monitoring and surveying technology, considering the properties of the radio-frequency, proposes the solution of monitoring and warning radio interference by using the daily monitoring and statistics data. The system is supported by GIS and monitoring database. Throw a brick to attract jade; if carry out the similar research in wireless management industry, it will enhance evidence in building a scientific system for the wireless alarming & monitoring system. Also the author hopes that the plan will be beneficial for preventing the radio interference in civil aviations wireless system.