JPH1168640A - Radio interference analytic method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate the occurrence ratio of radio interference related to radio equipment at the passing position of a mobile body by calculating the direction information of each satellite from the mobile body at the passing position and calculating the radio interference to the satellite except for one to be used for communication while using the direction information and previously stored radiation information. SOLUTION: Radiation beam data for each scanning beam of a phase array antenna as an evaluation object are previously stored in a storage part 2. When the passing position of an airplane on its desired flight route is inputted by an input part 1, a navigation calculation part 3 calculates the direction of watching each satellite from the airplane at each inputted passing position and determines the optimum satellite to be used for communication. Next, a radio interference arithmetic part 4 selects the beam optimum for the direction of the satellite to be used for this communication out of the scanning beam data stored in the storage part 2 concerning this satellite to be used for communication. Then, it is checked whether the side lobe level of the satellite direction not to be used for communication is higher than a threshold level or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio interference analysis method for evaluating radio interference related to unnecessary radiation from an antenna mounted on an aircraft in mobile satellite communications, particularly in aeronautical satellite communications.

[0002]

2. Description of the Related Art An Inmarsat aeronautical satellite communication system using an Inmarsat satellite has been put into practical use as one of communication systems for performing communication between an aircraft and the ground via a satellite. In this aeronautical satellite communication system, a high-gain antenna of a phased array system capable of directing a radiation beam having a gain of about 12 dBi in an arbitrary direction is used as an antenna mounted on an aircraft to perform voice communication and facsimile communication. Data transmission rate is 21Kbps
Communication. Such an aircraft-mounted phased array antenna usually calculates the direction of a satellite (satellite direction information) seen from the aircraft based on the aircraft position information output from an inertial navigation device mounted on the aircraft, and The beam scanning direction is controlled so that the beam of the phased array antenna is directed toward the satellite from the satellite direction information.

FIG. 2 is a conceptual diagram showing an Inmarsat geostationary satellite launched above the equator. Four Inmarsat geostationary satellites 21, 22, 23, and (24)
It is located at 36,000 km above the equator and covers communications with the entire earth. The flying aircraft uses a phased array antenna beam to select the most suitable satellite for communications from among the four satellites. To establish communication with the ground station.

Generally, when a phased array antenna scans a beam, it generates unnecessary radiation (side lobes) at a lower level than the radiation (main lobe) in the direction in which the beam is directed. It is known that the level of the side lobe becomes larger than that of the main lobe when the value exceeds a certain value. Therefore, depending on the position of the aircraft and the satellite and the angle at which the beam is scanned, the side lobe is directed to a satellite that is not used for communication at a certain level or more, and radio wave interference occurs to cause interference in a communication line. Therefore, in order to prevent this radio interference, it is necessary for the phased array antenna for aeronautical satellite communication to suppress the side lobe at the time of beam scanning to a specified value or less.

The radio interference ratio (the ratio of the number of points where radio interference occurs to the total number of evaluation points of radio interference) as a parameter representing the above-mentioned radio interference prevention performance caused by the antenna beam is set to a specified value or less. In order to evaluate the radio interference ratio, for example, the following method has been used. In other words, in the conventional radio interference analysis method, for example, the latitude and longitude are equally divided on the earth at intervals of 5 degrees, and at each division point, the antenna beam directed to the communicating satellite radiates in the direction of three satellites that do not communicate. The above-mentioned radio interference ratio was evaluated from the side lobe level.

[0006]

However, the evaluation using the conventional radio interference analysis method as described above has the following problems. That is, the route on which the aircraft actually flies is limited to a specific area on the earth by agreement of ICAO (International Civil Aviation Organization) and the like. Therefore, the radio interference ratio evaluated by the conventional radio interference analysis method is as described above. As described above, since the actual flight route is ignored and the latitude and longitude are uniformly evaluated at the division points divided by 5 degrees, the radio interference ratio generated in the communication between the aircraft and the satellite on the actual flight route is It was separated and could not be evaluated practically. For example, in the Inmarsat standard, if there is no radio interference at 85% or more of all evaluation points, the standard will be passed, so if the radiation beam of the antenna mounted on the moving object is at all evaluation points on the actual flight route, However, if radio interference does not occur at the remaining evaluation points, the above standard may be passed. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems related to the conventional radio wave interference analysis method, and is used in mobile satellite communication such as aeronautical satellite communication that occurs on an actual flight route of an aircraft (moving route of a moving object). It is an object of the present invention to provide a method capable of evaluating a radio interference ratio related to a radiation beam of an antenna used.

[0007]

According to a first aspect of the present invention, there is provided a radio interference analysis method according to the present invention, wherein a radio device mounted on a mobile object selects one of a plurality of satellites. Then, in a mobile radio system that performs radio communication via this, the radiation beam information of the antenna connected to the radio is stored in advance, and based on the passing position information of the mobile input by the evaluator, Calculating the direction information of each satellite from the moving object at the passing position, and calculating the radio wave interference to the satellites other than those used for communication using the direction information and the previously stored radiation beam information,
The rate of occurrence of radio wave interference related to the wireless device at the passing position of the moving object is evaluated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. The radio interference analysis method according to the present invention can be used to evaluate radio interference related to an antenna used in mobile satellite communication. For example, the radio interference analysis related to an airborne phased array antenna in aeronautical satellite communication can be used. The case of evaluating is described.

FIG. 1 is a block diagram showing an example of a processing flow when the radio interference analysis method according to the present invention is carried out. The processing flow shown in this example includes an input unit 1 for inputting a passing position of an aircraft as a moving object in a flight route, a storage unit 2 for storing radiation beam information for each scanning beam of an antenna mounted on the aircraft, and A navigation operation unit 3 for calculating the directions of a plurality of satellites at the passing position of the aircraft; and a radio wave interference (ratio) to a satellite not used for communication among the plurality of satellites at the passing position of the aircraft in the storage unit 2. And a radio wave interference calculation unit 4 that calculates using the radiation beam information stored in the navigation calculation unit 3 and the direction information of each satellite obtained by the navigation calculation unit 3.

When radio interference is evaluated using the radio interference analysis method according to the present invention, it is necessary to previously store radiation beam data for each scanning beam of the phased array antenna to be evaluated in the storage unit 2. . In the radio interference analysis method according to the present invention, first, when a user of the method inputs a passing position on the flight route of a desired aircraft through the input unit 1, the navigation operation unit 3 transmits the aircraft at each of the inputted passing positions. Calculate the viewing direction of each satellite from, and determine the optimum satellite to use for communication. Next, the radio interference calculation unit 4 selects an optimum beam in the direction of the satellite used for the communication from the scanning beam data stored in the storage unit 2 for the satellite used for the communication, and By using the radiation beam data, it is possible to check whether or not the side lobe level in the satellite direction not used for communication is equal to or higher than the threshold level to determine the presence or absence of radio wave interference.

As described above, the radio wave interference analysis method according to the present invention can evaluate the radio wave interference ratio of a phased array antenna mounted on an aircraft on an actual flight route to a satellite not used for communication.

[0012]

According to the present invention, as described above, the processing flow is constituted by the input unit, the storage unit, the navigation operation unit, and the radio wave interference operation unit. Radio interference according to the route can be evaluated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a processing flow when a radio interference analysis method according to the present invention is performed.

FIG. 2 is a conceptual diagram illustrating an Inmarsat geostationary satellite located above the equator.

[Explanation of symbols]

1. Input unit 2. Storage unit 3. Navigation operation unit 4. Radio interference operation unit 21, 22, 23, (24) Inmarsat geostationary satellite 25 Earth

Claims (1)

[Claims] 1. A mobile radio system in which a radio device mounted on a mobile device selects one of a plurality of satellites and performs radio communication via the radio device, wherein radiation beam information of an antenna connected to the radio device is provided. Is stored in advance, and based on the passing position information of the moving body input by the evaluator, the direction information of each satellite from the moving body at the passing position is calculated, and the direction information and the previously stored radiation beam are calculated. A radio interference analysis method, comprising calculating radio interference with satellites other than those used for communication using information and evaluating a rate of occurrence of radio interference with respect to the wireless device at a passing position of the moving object.