NOXX20 KWBC 291923

ADMEMW

NATIONAL ADMINISTRATIVE MESSAGE FOR EMWIN

NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC

330 PM EDT FRI JUN 29 2001

TO: EMERGENCY MANAGERS WEATHER INFORMATION NETWORK /EMWIN/

USERS

FROM: WILLIAM BROCKMAN

CHIEF...TELECOMMUNICATION OPERATIONS CENTER

NATIONAL WEATHER SERVICE /NWS/

AND

GERALD DITTBERNER

CHIEF...ADVANCED SYSTEMS PLANNING DIVISION

NATIONAL ENVIRONMENTAL SATELLITE...DATA...AND

INFORMATION SERVICE /NESDIS/

SUBJECT: EMWIN TRANSITION UPDATE 6/29/01

THIS MESSAGE IS THE SECOND IN A SERIES OF TRANSITION UPDATE

MESSAGES TO INFORM EMERGENCY MANAGERS WEATHER INFORMATION NETWORK

/EMWIN/ USERS OF NEW INFORMATION REGARDING THE TRANSITION OF THE

EMWIN DATASTREAM. THE FIRST EMWIN TRANSITION UPDATE...DATED

APRIL 27...AND FUTURE EMWIN TRANSITION UPDATES WILL BE

DISTRIBUTED THROUGH EMWIN AND POSTED ON THE EMWIN HOME PAGE AT

/USE LOWER CASE/:

index.htm

THE EMWIN HOME PAGE HAS BEEN REVISED AND UPDATED. WE USED THE

MANY EMAILS AND DISCUSSION GROUP TOPICS THAT RESULTED FROM THE

APRIL 27 EMWIN TRANSITION UPDATE TO CREATE A LIST OF FREQUENTLY

ASKED QUESTIONS. AS WE RECEIVE ADDITIONAL QUESTIONS...WE WILL

ADD TO THE EMWIN FAQS THAT ARE LOCATED ON THE EMWIN HOME PAGE.

HERE IS A BRIEF RECAP...EMWIN IS NOW BROADCAST FROM GOES

/GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE/ EAST AND WEST

SATELLITES. THE FINAL SATELLITE OF THE CURRENT SERIES /GOES-M/

IS SCHEDULED TO BE LAUNCHED IN JULY 2001. CURRENTLY...GOES-N IS

SCHEDULED FOR LAUNCH AND STORAGE IN ORBIT IN FEBRUARY 2003.

TRANSITION OF THE EMWIN BROADCAST TO GOES-N WILL NOT OCCUR UNTIL

SOMETIME BETWEEN 2003 AND 2005 /BARRING MULTIPLE CATASTROPHIC

SATELLITE FAILURES/.

EMWIN CAN NOT BE BROADCAST IN ITS CURRENT FORM ON THE GOES SERIES

N THROUGH Q. MAJOR DIFFERENCES ARE:

- THE NEW SERIES OF SATELLITES WILL BROADCAST A DIGITAL SIGNAL

RATHER THAN THE CURRENT ANALOG

- THE EMWIN SIGNAL WILL USE A DEDICATED TRANSPONDER RATHER THAN

SHARE A CHANNEL AS IS CURRENTLY DONE

- THE EMWIN SIGNAL WILL CONFORM TO INTERNATIONAL REGULATIONS FOR

POWER FLUX DENSITY RESULTING IN REDUCED EMWIN BROADCAST POWER

LEVELS...AND

- EMWIN BROADCAST FROM GOES-N THROUGH Q WILL REQUIRE DIFFERENT

MODULATION CHARACTERISTICS.

IN EARLY JUNE 2001...THE GOES-11 SPACECRAFT WAS TAKEN OUT OF

ON-ORBIT STORAGE TO PERFORM A SERIES OF TESTS SIMULATING THE

GOES-N ENVIRONMENT. THE TESTS CONFIRMED THE CURRENT SPACECRAFT

SERIES /GOES-I THRU M/ CAN SUPPORT ALTERNATIVE TRANSITION

SCENARIOS. THESE SCENARIOS INCLUDE OPERATING EITHER WEFAX OR

LOW-RATE INFORMATION TRANSMISSION /LRIT/ WITH EITHER THE CURRENT

EMWIN OR A SIMULATED /NOT AT THE FINAL GOES-N FREQUENCY/ GOES-N

EMWIN. THE WIDER CHOICE OF TRANSITION ALTERNATIVES MAY PROVIDE

THE OPPORTUNITY FOR A SIMULATED GOES-N EMWIN CHANNEL /DIGITAL...

BPSK WITH FORWARD ERROR CORRECTING CODING...BUT AT THE PRESENT

RECEIVER FREQUENCY/ BEFORE GOES-N BECOMES OPERATIONAL.

AN INEXPENSIVE CHIP SET INCORPORATING A FORM OF FORWARD ERROR

CORRECTION CALLED TURBO CODING HAS RECENTLY BECOME AVAILABLE. A

STUDY IS BEING CONDUCTED TO DETERMINE THE FEASIBILITY OF USING

TURBO CODING IN THE GOES-N EMWIN MODULATION. IF SUCCESSFUL...

THE NEW CHIP SET WOULD PROVIDE A LOW COST ALTERNATIVE TO THE CHIP

SET ORIGINALLY PROPOSED FOR A GOES-N EMWIN DEMODULATOR.

ADDITIONAL GOES-N THROUGH Q BROADCAST SIMULATIONS USING CURRENT

SATELLITES WILL BE CONDUCTED LATER THIS YEAR TO PROVIDE THE

TECHNICAL INFORMATION NECESSARY FOR THE DESIGN OF NEW DIGITAL

RECEIVER SYSTEMS.

ANSWERS TO MOST QUESTIONS RECEIVED AT THE EMAIL ADDRESS BELOW

WILL BE ADDED TO THE EMWIN FAQS ON THE EMWIN HOME PAGE:

Emwin.System@noaa.gov

THE COMPLETION OF THE EMWIN TRANSITION IMPLEMENTATION STUDY

PLANNED FOR EARLY JUNE 2001 IS NOW EXPECTED AT THE BEGINNING OF

AUGUST 2001. THE NEXT TRANSITION UPDATE MESSAGE IS PLANNED

SHORTLY AFTER THE STUDY/S COMPLETION.

END

NNNN

--------------E9F5388E15C67FE09C9EF427--