WMO Radio Spectrum Workshop- Radiosonde Spectrum Issues Presented By: David Franc Office of Radio Frequency Management March 2006

2 Purpose Provide information on current status of radio frequency issues that may impact global radiosonde operations

3 Outline Definitions ITU-R Recommendations History- Past Issues Current Issues –Meteorological Satellites –COSPAS-SARSAT –Optical Metaids –Equipment Standards Important Points

4 Definitions International Telecommunications Union (ITU) – U.N. organization responsible for international regulation of radio spectrum use International Radio Regulations – Treaty text maintained and enforced by the ITU that provides the regulations and table of frequency allocations for international radio spectrum use Radio Service - A type of radio operation, such as meteorological satellites, broadcasting, mobile-satellite Allocation – The authority for a radio service to use a particular frequency band License (or Assignment) – Authority for a particular radio station to use a specific frequency under the defined technical conditions and consistent with a frequency allocation

5 Definitions Applied to Radiosondes In the ITU, radiosondes fall under the radio service of meteorological aids (metaids) –Metaids include dropsondes and rocketsondes ITU Working Party 7C (WP 7C) is responsible for metaids Metaids allocations: – 406 MHz, – 1700 MHz and 35.2 – 36 GHz Metaids stations are licensed or provided frequency assignments by the country in which they operate

6 ITU Regions Source: ITU Radio Regulations, 2004 Edition

Metaids ITU-R Recommendations

8 Access to ITU-R Recommendations Available at: Copyrighted material- must be purchased –Single recommendation –Full series on CD –Yearly subscription May obtain 3 free recommendations per year

9 ITU-R SA.1165 Content: Technical characteristics, operational characteristics, and performance criteria for metaids systems Use: Provides technical and operational characteristics to others conducting sharing studies Recently updated and is passing through the ITU-R approval process

10 ITU-R SA.1263 Content: Interference criteria for metaids systems Use: Provides aggregate interference levels for conducting sharing studies Currently under revision in ITU-R WP 7C

11 ITU-R SA.1262 Content: Sharing and coordination criteria (levels applicable to individual interference sources) Use: Provides single entry interference levels for conducting sharing studies This recommendation is out of date and will be updated upon completion of the ITU-R SA.1263 update

12 ITU-R SA.1264 Content: Addresses sharing between the mobile-satellite service and metaids Use: Supported the work of the WRCs (WRC-97 through WRC-2003) This recommendation is obsolete and is recommended for suppression

13 ITU-R SA.1258 Content: Sharing between meteorological satellite (metsat) and Earth exploration satellite service (EESS) uplinks, and metaids in the band MHz Use: Support work of WRC-97 Needs to reviewed by WP 7C

14 ITU-R SA.1346 Content: Recommended interference mitigation techniques for medical implant devices operating in the MHz band Use: Guidance to administrations developing rules for medical implant devices Needs to be reviewed by WP 7C

15 ITU-R SA.[OPTICAL METAIDS] Content: Technical and operational characteristics of metaids devices operating in the optical frequency range Use: Information to the ITU-R Passing through the ITU-R approval process- currently on the ITU-R website as document SA.7BL7

16 ITU-R SA.[USE 1.7 GHz] Content: Facilitate sharing between metaids and metsat in MHz Use: Guidance to metaids and metsat operators for selection of operating frequencies Passing through the ITU-R approval process- currently on the ITU-R website as document SA.7BL8

History- Metaids Spectrum Issues

18 History- Metaids Spectrum Issues The bands MHz and MHz were identified as potential sources of spectrum for the mobile-satellite service (MSS) in MHz allocated worldwide to MSS at WARC MHz allocated in ITU Region 2 (N. and S. America) to MSS at WARC-92

19 History- Metaids Spectrum Issues (continued) Studies within the ITU show that the MSS would cause interference to metaids if common spectrum is used by both Proposals were made to WRC-95, WRC-97 and WRC-2000 for additional allocations to MSS in both metaids bands No action taken by WRC-95, WRC-97 or WRC-2000 WRC-2003 was held June 2003

20 History- Outcome of WRC-2003 No MSS allocation proposals in MHz MSS an allocation in MHz Suppressed Region 2 allocation in MHz Radio Regulations Footnote 5.379E –Encourage metaids operations move out of MHz –Metaids in China, Iran (Islamic Republic of), Japan, and Uzbekistan are protected from MSS interference Completed work on MSS sharing with metaids

21 Summary of Past Issues Current MSS allocations in MHz and MHz MSS operations in MHz will cause metaids data loss Radio Regulations Footnote 5.379E –Metaids operations in – 1675 MHz should be avoided No future actions for MSS spectrum anticipated

Current Metaids Spectrum Issues Meteorological Satellites COSPAS-SARSAT Optical Metaids Equipment Standards

23 Meteorological Satellites Share MHz and MHz Metaids cause interference to meteorological satellite (metsat) ground receivers in –1700 MHz Metaids/metsat coordination has been ineffective in the past- is improving due to the actions of SG-RFC New ITU Recommendation developed by Study Group 7

24 Meteorological Satellites- Study Group 7 Recommendation Avoid interfering with metsat user stations operating above 1683 MHz –Metaids operations should be limited to the frequency range MHz –Metsat operations avoided in the range MHz –Metsat downlinks to the main CDA stations may still extend into MHz

25 COSPAS/SARSAT COSPAS/SARSAT is a satellite-based search and rescue system for locating emergencies, operating at MHz Some metaids transmitters and associated windfinding radars are suspected of causing interference to the satellite receiver Interference can prevent detection of a life- threatening emergency situation Causes: –Metaids signals drifting above 406 MHz –Transmitter unwanted emissions above 406 MHz

26 Optical Metaids The ITU-R is collecting information on devices operating at optical frequencies ITU-R is not regulating frequency use in the optical range WP 7C recommendation- optical metaids technical and operational characteristics –sensor types: precipitation, visibility, sunshine and laser ceilometers

27 Equipment Standards Under development in Europe and in other administrations Will improve interference immunity and reduce spectrum use More details in later briefing

Important Points for Members

29 Improve Radiosonde Transmitters Inefficient use of radio spectrum can lead to forced reduction of available spectrum WMO- radiosondes are being improved and spectrum requirements will decrease Reduce spectrum requirements by reducing transmitter bandwidth, drift and unwanted emissions Limit radiosonde operations to the allocated bands and preferably to the sub-bands recommended by the SG-RFC and ITU-R WP 7C

30 Document Radiosonde Characteristics and Operations Recommendation SA.1165 documents radiosonde characteristics and operations SA.1165 forms the basis for assumptions used in conducting spectrum sharing studies Information is missing on Asia, Africa, and S. America Members should submit information on their systems and operations to ITU Working Party 7C or the SG-RFC

31 Work with Your National Spectrum Regulators Every administration that is a member of the ITU-R has a national spectrum regulatory organization Members should develop a working relationship with their spectrum regulatory agency –Raise awareness of national spectrum regulators to national meteorological spectrum requirements –Provides a mechanism for coordinating national responses to proposals that could impact meteorological operations

32 Conclusion The meteorological community should strive to deploy radiosonde systems that: –Decrease spectrum requirements and make efficient use of radio spectrum –Eliminate interference to other services Become involved at the national level to ensure meteorological spectrum requirements are adequately defended Participate in ITU-R meetings if resources allow