Radio waves emitted from illegally modified radio equipment, or unlicensed equipment, can cause TV reception and radio signal problems, or obstruct radio signals used by the fire department, ambulances, and trains, which could result in serious threat to human safety concerns.
With increasing importance being placed on environmental protection relevant to radio wave use, more efficient and effective means of radio-wave monitoring is needed to prevent and strengthen controls on a rising number of unlicensed radio stations.
Since FY1993, the Ministry of Internal Affairs and Communications (MIC) has used spectrum user fees to maintain facilities for improvement of radio wave monitoring. As part of such activities, DEURAS System, main monitoring system for radio waves which detects unlicensed radio waves, has been developed and is being installed in main cities across Japan.
(DEURAS: DEtect Unlicensed RAdio Stations)
(1) DEURAS-D System
DEURAS-D system locates unlicensed radio stations by detecting the direction of radio emissions or monitoring radio reception from stationary sensor stations mounted atop buildings or vehicles, or from vehicle-mounted mobile sensors.
(2) DEURAS-H System(Shortwave Monitoring System)
DEURAS-H System is composed of five sensor stations throughout Japan which detect the direction of radio wave in the shortwave (300kHz to 30MHz) band, and of a main central station (located at the Kanto Bureau of Telecommunications) and regional central stations which remotely control the sensor stations via dedicated lines. Through remote control of sensor stations by the main central stations, the system detects the location of radio broadcast sources.
(3) DEURAS-S System (Space Radio Monitoring System)
DEURAS-S System is a system that receives radio wave from geostationary and orbiting satellites, identifying the location of orbiting satellites and quality of radio wave (frequency, etc.), and determining whether each one is operating properly in accordance with international agreements and international adjustment results.
Information obtained from this system is utilized to ensure administration of satellites on an international level.
Orbiting satellite monitoring antenna Geostationary satellite monitoring antenna Main central station
(4) Maintenance Plans for DEURAS System
The construction and enhancement of DEURAS System is taking place over seven terms beginning in FY1993.
|First Term(FY1993 - FY 1995)||Second Term(FY1996 - FY1998)||Third Term(FY1999 - FY2001)||Fourth Term(FY2002 - FY2004)||Fifth Term(FY2005 - FY2007)||Sixth Term(FY2008 - FY2010)||Seventh Term(FY2011 - FY2013)|
|DEURAS System||Construction of sensor stations in key cities, particularly Tokyo and the other major cities designated by government ordinance, and prefectural capitals||Construction of sensor stations in cities with populations of more than 100,000||Construction of sensor stations in cities with populations of more than 50,000||Construction of sensor stations in cities with populations of more than 30,000 inhabitants which receive constant reports of interference or disturbance||Improvement and updating of systems installed during the first through fourth terms|
|DEURAS-H System||Construction of main central station and sensor stations||Improvement and updating of systems installed during the first through third terms|
|DEURAS-S System||Construction of DEURAS-S System (L/S/C/Ku/Ka bands)||Construction of DEURAS-S System (VHF/UHF bands)||Improvement and updating of systems installed during the second and third terms|
Unlicensed radio stations not only disrupt and interfere with important radio communications and general operational radio, some also generate illegally powerful radio waves that interfere with neighboring television and radio, or cause disruptions to cellular phone service.
The following shows the number of unlicensed radio stations detected thus far by Bureaus of Telecommunications in each region of Japan. These stations are being dealt with through legal prosecution or administrative guidance as needed.
Using the DEURAS System, we intend to continue and reinforce the effort to detect and eliminate unlicensed radio stations.
|Change in radio monitoring budget (unit: 100 million yen)|
|Phase of maintenance plan||First Term||Second Term||Third Term||Fourth Term||Fifth Term||Sixth Term||Seventh Term|
|No. of facilities||19.1||15.7||31.4||42.2||34.7||28.6||23.5||26.7||34.6||28.4||28.4||34.3||33.3||35.4||37.2||31.5||24.5||26.5||23.6||26.5||-|
|Maintenance and operation||7.4||5.1||12.4||16.8||20.0||29.1||39.8||49.5||34.7||33.0||36.6||31.1||30.1||27.0||31.3||29.4||26.9||25.5||28.4||26.6||-|
|Expenses for publicity and information dissemination activities||1.4||1.8||1.8||3.8||6.1||7.3||9.6||10.7||11.6||9.2||7.2||6.9||6.9||6.7||7.4||7.4||3.6||3.5||3.3||3.5||-|