# Presentation: 112228

## A Time of Transition for EMWIN

- William A. Johnson

- December 11, 2006

**Notes:**
Acknowledge key members of the audience
Emphasize that this is for the vendors
Questions are welcome but intra-NOAA may be taken off-line for later meeting

## OVERVIEW

- The GOES satellites
- Summary of inherent EMWIN advantages
- What must change?
- When could changes occur?
- Getting ready – brief chronology
- Transition objectives
- System design & specifications
- Prototype receiver design & construction
- Field test results
- Transition planning
- Current international activities
- For more information
- Vendor input needed
- Conclusion

- William A. Johnson

- December 11, 2006

**Notes:**
A high level presentation, with only occasional lapse into high tech jargon
Bringing the audience up to or down to the same level

Forgive me if I cannot explain everything; my recollection of satellite technology goes back to AT&T’s Telstar; anyone here still remember Telstar?
Fortunately, I have younger members of the team here who can answer more; and if we can’t we can give you a call-back

## The NOAA GOES Satellites

- The mission of the  _[Geostationary Operational Environmental Satellites](http://www.goes.noaa.gov/)__ (GOES)_
- The GOES program goes back to 1975 with the launch of the first of the GOES A-F series of satellites.
- Many of the sub-systems aboard the GOES satellites produce specialized weather information of a technical nature useful primarily to scientists, especially meteorologists and climatologists
- The important inclusion of a communications transponder as one of the subsystems
- Essentially for real-time weather facsimile information (WEFAX); now replaced by the Low Rate Information Transmission (LRIT) system.
- The spare bandwidth on the transponder allowed the inclusion of a narrow band EMWIN channel after the advent of the GOES I/M series in 1994

- William A. Johnson

- December 11, 2006

**Notes:**
The Geostationary Operational Environmental Satellites (GOES) The GOES system maintains a continuous data stream from a two-GOES system in support of the National Weather Service requirements. These satellites send weather data and pictures that cover various sections of the United States. Current weather satellites can transmit visible or infrared photos, focus on a narrow or wide area, and maneuver in space to obtain maximum coverage.
The GOES program goes back to 1975 with the launch of the first of the GOES A-F series of satellites.
Each satellite in the series carries two major instruments: an Imager and a Sounder. These instruments acquire highresolution visible and infrared data, as well as temperature and moisture profiles of the atmosphere. They continuously transmit these data to ground terminals where the data are processed for rebroadcast to primary weather services both in the United States and around the world, including the global research community. 
Many of the sub-systems aboard the GOES satellites produce specialized weather information of a technical nature useful primarily to scientists, including professional meteorologists.
But the GOES satellites also include a communications subsystem transponder that serves dissemination of real-time weather products to those with compatible receiving equipments.  Initially, this transponder provided the Weather Facsimile Data (WEFAX) but the transponder has spare bandwidth.  With the advent of the GOES I/M satellite series first launched in 1994 it was also possible to include a narrow bandwidth EMWIN signal as an experiment.

## The NOAA GOES Satellites, cont’d

- Bandwidth comparison of the communications transponders for the GOES-I/M Generation with the GOES N/P Generation
- GOES I/M:  1 mHz bandwidth for both LRIT and EMWIN
- GOES N/P:
- Separate transponders for LRIT and EMWIN.
- EMWIN transponder bandwidth is 50 kHz

- William A. Johnson

- December 11, 2006

**Notes:**
The Geostationary Operational Environmental Satellites (GOES) The GOES system maintains a continuous data stream from a two-GOES system in support of the National Weather Service requirements. These satellites send weather data and pictures that cover various sections of the United States. Current weather satellites can transmit visible or infrared photos, focus on a narrow or wide area, and maneuver in space to obtain maximum coverage.
The GOES program goes back to 1975 with the launch of the first of the GOES A-F series of satellites.
Many of the sub-systems aboard the GOES satellites produce specialized weather information of a technical nature useful primarily to scientists, including professional meteorologists.
But the GOES satellites also include a communications subsystem transponder that serves dissemination of real-time weather products to those with compatible receiving equipments.  Initially, this transponder provided the Weather Facsimile Data (WEFAX) but the transponder has spare bandwidth.  With the advent of the GOES I/M satellite series first launched in 1994 it was also possible to include a narrow bandwidth EMWIN signal as an experiment.

## Summary of Inherent EMWIN Advantages

- No recurring cost for satellite service
- Large GOES satellite footprint - full CONUS coverage
- Use of L band - invulnerable to precipitation fading
- Redundant GOES satellite coverage for CONUS
- Extremely valuable to island nations
- Essential service available during times of fiber or wire outage
- Existing base of government & private users
- Watch & warning dissemination in < 1 minute
- High portability of receiver with small antenna & use of laptop

- William A. Johnson

- December 11, 2006

## What must change?

- With the advent of GOES-N/P satellite generation
- Broadcast power must be reduced to comply with the  International Telecommunication Union (ITU) power limits:
- From:  51.0 dBmi (minimum EIRP)
- To:      44.8 dBmi (minimum EIRP)
- Frequency must change:
- From:  1690.725 MHz
- To:	 1692.700 MHz

- William A. Johnson

- December 11, 2006

**Notes:**
Reduced to 1⁄4 power and shift the frequency
A substantial challenge to radio design engineering skill 

## When Could Changes Occur?

- 2006 - 2011
- GOES-N launch
- May 24, 2006
- GOES-N Operational
- First broadcast of new EMWIN-N service depends upon:
- Fuel usage for both GOES 11 or 12
- Subsystem health
- Demand for new technology
- Fuel exhaust date for existing GOES constellation is 2011
- GOES-O launch
- As early as April 2008

- William A. Johnson

- December 11, 2006

**Notes:**
NESDIS color charts
Technology changes between present GOES generation and GOES N,O,P not huge

## Transition Objectives

- NWS & NESDIS teamwork
- Retain inherent EMWIN advantages
- Minimize cost to user for transition
- Any new receiver design must work on both current and new GOES system
- Listen to users & vendors and keep them informed
- Establish overall system design specifications
- Design, construct & test a proof-of-concept prototype receiver
- Release schematics and operating software to industry for vendor guidance
- Prepare and maintain a transition plan

- William A. Johnson

- December 11, 2006

**Notes:**
Acknowledge great contribution by NESDIS and its contractors; Angelo Wade supported by Peter Woolner, Bill Webber and Avtec

## Getting Ready – Some Chronology Highlights

- NWS /NESDIS task team formed – late 2003
- With AVTEC as NESDIS contractor
- User-vendor conference – April 2004
- Presented a 9.6 kbps version prototype
- Users & vendors wanted increased data rate and lowest possible cost
- Goals for transition project changed to incorporate user/vendor requests – June, 2004
- GOES-N launch – May 2006
- Successful test of prototype via GOES-N – Sept. 2006
- Request for Information issued on FedBizOps – Nov. 2006

- William A. Johnson

- December 11, 2006

**Notes:**
Special thanks to our colleagues at NESDIS and their contractors, especially Angelo Wade supported by Bill Webber (CSC) and Peter Woolner (Mitretek)
Special praise for AVTEC

## System Design & Specifications

- Complete documentation available on EMWIN website:
- _[http://](http://www.nws.noaa.gov/emwin/index.htm)__[www.nws.noaa.gov/emwin/index.htm](http://www.nws.noaa.gov/emwin/index.htm)_
- EMWIN-N Signal specification includes data on:
- Compliance with Consultative Committee for Space Data Systems (CCSDS)
- Downlink frequency & modulation
- User data rate
- Radio frequency symbol rate
- Pulse shape filter
- Satellite transmit Equivalent Isotropically Radiated Power (EIRP)
- Forward Error Correction Code (FEC)
- Block Channel Access Data Unit (CADU) size
- Attached sync marker
- Randomization
- Link budget

- William A. Johnson

- December 11, 2006

## Prototype Receiver Design Concepts & Goals

- Minimum dish antenna size will be retained at one meter –
- Provide an operating margin of at least 5.5 dB
- Use of Offset Quadrature Phase Shift Keying (OQPSK) modulation and forward error correction to compensate for lower power level
- Software-defined radio concepts to be used for demodulation and decoding functions
- Hardware implementation schemes for intermediate frequency conversion and analog/digital conversion
- Must be capable of receiving either existing GOES I/M signal or new GOES N/P signal

- William A. Johnson

- December 11, 2006

## Offset Quadrature Phase Shift Keying

- A version of** **_**[phase-shift keying](http://en.wikipedia.org/wiki/Phase-shift_keying)**_ modulation which uses 4 different phase values of the phase to transmit.
- It is also known as “'Staggered quadrature phase-shift keying (SQPSK).
- Regular quadrature phase-shift keying (QPSK) has the disadvantage of allowing a possible 180 degree phase shift for certain bit combinations resulting in undesirable amplitude fluctuations in the signal.
- By off-setting the timing of the odd and even bits in the data stream the phase shift of the resultant output stream will be limited to 90 degrees yielding less amplitude fluctuations.

- William A. Johnson

- December 11, 2006

## Software Defined Radio

- "In a software-defined radio, functions that were formerly carried out solely in hardware, such as the generation of the transmitted signal and the tuning and detection of the received radio signal, are performed by software that controls high-speed signal processors.“
- FCC Definition

- William A. Johnson

- December 11, 2006

##            The 19.2 kbps Prototype 

- William A. Johnson

- December 11, 2006

## IF Adapter Functions

- Converts signal from Low Noise Block (LNB) at approximately 137.225 MHz down to audio frequencies
- Provide gain
- Make output compatible with standard stereo sound card interface
- Provide In-phase (I) & Quadrature (Q) inputs to sound card
- Power source for L-band downconverter
- Crystal change needed to move from current EMWIN broadcast to new EMWIN broadcast

- William A. Johnson

- December 11, 2006

## Intermediate Frequency Adapter

- William A. Johnson

- December 11, 2006

## Sound Card

- Stereo sound card functions as a low-cost, readily available analog-digital converter
- Interface to IF adapter to accept I & Q inputs for digital sampling
- Prototype solution expected to work with most available newer PC sound cards
- Minimum sampling rate must be at least 44.1 kHz, preferably 48 kHz
- Laptop installations will normally require an external card

- William A. Johnson

- December 11, 2006

## Prototype Minimum PC Requirements

- 350 MHz Pentium II, or faster
- Stereo sound card capable of simultaneous sampling at 48 KHz
- Windows 2000, NT or XP operating system
- Installed Internet Protocol stack
- Two RS-232 ports
- > 160 MB memory
- EMWIN decoder/demodulator software
- EMWIN display software

- William A. Johnson

- December 11, 2006

##      The Prototype Software Demodulator Components 

-      The Prototype Software Demodulator Components

- William A. Johnson

- December 11, 2006

## Software Availability

- Down-loadable software (dynamic link libraries or DLL) available on EMWIN website:
- _[http://](http://www.nws.noaa.gov/emwin/index.htm)__[www.nws.noaa.gov/emwin/index.htm](http://www.nws.noaa.gov/emwin/index.htm)_

- William A. Johnson

- December 11, 2006

## Field Test Results for Prototype

- Testing via GOES-N at NOAA Wallops Command & Data Acquisition site in Sept. 2006
- Copy of final test report (available) shows receive system margin of 5.5 dB

- William A. Johnson

- December 11, 2006

## Field Test Results

- William A. Johnson

- December 11, 2006

**Notes:**
Green shows the “waterfall” curves

## A Possible Transition Scenario

- William A. Johnson

- December 11, 2006

## Mid 2006 – Late 2006

- EMWIN - I

- GOES-N Uplink
-  processor

- 1690.725 DFSK 9.6kbps

**Approx. 30 days after launch , GOES-N 19.2 testing begins (Sept.2006)**

- 1690.725 DFSK 9.6kbps

**GOES 10 nearly out of fuel, plan is for GOES 10 to be replaced by GOES 11 (about June 28,2006)**
**GOES 10 drifted to 60 degrees W for possible use by Argentina or Brazil (unofficial)**

- 1692.700 Offset QPSK 19.2kbps

**Mid 2006 – Late 2006**

**135W**

**75W**

- William A. Johnson

- December 11, 2006

**GOES 12 (EAST)**

- EMWIN - I

- EMWIN -N

- 1690.725 DFSK 9.6kbps

- 1690.725 DFSK 9.6kbps

- EMWIN N Cutover GOES East

**Cutover date is sometime between 2007 and 2011**

**GOES N replaces GOES 12**

- 1692.700 Offset QPSK 19.2 kbps

- William A. Johnson

- December 11, 2006

**GOES N (EAST)**

**GOES 11 (WEST)**

- EMWIN - N

- 1690.725 MHz DFSK

- EMWIN -I

- 1692.700 Offset QPSK 19.2  FEC

- Sometime between 2007 - 2011 operational scenario

- WALLOPS

- WALLOPS

- William A. Johnson

- December 11, 2006

## 200? to 2011 Final cutover    

**                  ****(WEST)**

- 200? to 2011 Final cutover

** ****200? To 2011 GOES O  replaces GOES  11**

- EMWIN -N

- 1692.700 MHz

- EMWIN -I

- 1690.725 dfsk

** ****Final Cutover to EMWIN N**

- William A. Johnson

- December 11, 2006

## CONUS users (most)  not ready to transition can re-point to GOES west (EMWIN-I) until latest date 2011

- William A. Johnson

- December 11, 2006

## For More Information

- Updates posted on the EMWIN website - _[http://www.nws.noaa.gov/emwin/index.htm](http://www.nws.noaa.gov/emwin/index.htm)_
- Sign up for  the EMWIN mailing list, if not already on it
- EMWIN user groups on Yahoo – tech.groups.yahoo.com/group/emwin users/
- Local outreach programs
- Via Warning Coordination Meteorologists in NWS Weather Forecast Offices
- Special conferences, such as
- Southeast U.S. EMWIN Workshop at Huntsville, AL, 2004 and 2006

- William A. Johnson

- December 11, 2006

## International ActivitiesThird Border Initiative (TBI)

- A 2001 initiative by President Bush to aid the Caribbean island nations via a broad package of programs.
- One of these programs will increase funding for Disaster Preparedness and Mitigation efforts to shield critical commercial and environmental infrastructure from natural disasters, such as hurricanes.
- NWS, in consort with the NOAA International Affairs Office, will set up an EMWIN training program and provide EMWIN-I receiving systems to five island nations

- William A. Johnson

- December 11, 2006

## Current International ActivitiesGOES-10 Move

- NOAA is repositioning GOES-10 satellite to 60 degrees West to improve coverage over South America
- Continent will benefit from emerging Global Earth Observation Network
- Shift will help protect lives and property in North, Central and South America by significantly improving satellite detection of natural hazards.
- Will further strengthen the WMO's World Weather Watch Global Observing System.
- LRIT/EMWIN transponder not yet assigned for service in its new position

- William A. Johnson

- December 11, 2006

## Notes to Vendors 

- Proof-of-concept prototype must not be interpreted as a constraint on any workable implementation, whether via hardware or software
- Some possible concerns:
- Answers to questions about the prototype design?
- A satellite-based test bed?
- Grants to aid disadvantaged areas to purchase systems?
- Other?

- William A. Johnson

- December 11, 2006

## Are there any questions?

- William A. Johnson

- December 11, 2006