EMWIN
Transition Plan
EMWIN
Transition Plan
Introduction
Changes to the NOAA’s GOES N-series satellite frequency assignments and transponder characteristics will require corresponding upgrades to the National Weather Service (NWS) Emergency Managers Weather Information Network (EMWIN) broadcast from the GOES satellites. The National Environmental Satellite, Data, and Information Service (NESDIS), responsible for satellite and ground system design and implementation, and the NWS are working together to plan for the implementation and transition of the new EMWIN services within the future GOES N-series – the GOES-N, -O, and -P. This EMWIN implementation and transition plan identifies the related issues and actions required to achieve a successful transition. The GOES related broadcast changes consist of a:
q Change in the broadcast frequency … from 1690.725 MHz to 1692.700 MHz
q Reduction in the power level of the broadcast … from 51 dBmi to 43 dBmi to meet ITU regulations.
q Change of signal modulation … from Frequency Shift (FSK) to Binary Phase Shift Key (BPSK), and
q Introduction of Forward Error Correction Coding (FEC) … using a Reed-Solomon Convolutional Code
q Replacement of WEFAX … by LRIT.
The EMWIN data rate will remain as it is currently at 9.6 Kbps. The EMWIN data content will also remain the same.
A transition from current EMWIN operations (EMWIN-I) to the GOES N-series era EMWIN operations (EMWIN-N) is required as a result of these changes. This plan documents those required activities to develop, test, and make available a new EMWIN receiver system to the vendor community for the transition.
The EMWIN mission is the timely dissemination of NWS warnings, watches, forecasts, and other products to the nation’s emergency management community, and many other public and private organizations. A goal of EMWIN is low user cost access to a live stream of weather data and other critical emergency information. One means of providing this access is dissemination through the GOES satellites, and direct reception with a low cost receiving system. In some communities, the EMWIN signal received from GOES is then rebroadcast by the NWS and other public and private agencies as an audio signal on a dedicated VHF or UHF radio frequency. This rebroadcast signal can be received, by anyone within the 40-50 mile broadcast area, using an inexpensive radio receiver, a demodulator, and a personal computer.
When the GOES N-series becomes operational it will render current EMWIN receiver systems unable to receive and process the EMWIN datastream and thus will require changes to existing EMWIN receiver systems in order for users to continue to receive and demodulate the EMWIN-N broadcast. The new receiver systems are needed to accommodate the changes in frequency and modulation technique and the addition of Forward Error Correction. NOAA plans to minimize the impact of these changes on both the receiver system vendor community and the user community by building in a transition period in which new receiver systems are designed, built, marketed, and become operational. During this period the existing EMWIN-I broadcasts will continue and early coordination with the user community conducted.
The first launch of a GOES N-series satellite is currently planned for December 2004. A six-month checkout period is planned for January through June 2005. If the then-current constellation has experienced no problems (likely GOES-10 and –12), following the checkout period, the satellite will be placed in a storage orbit until it is needed. It is now planned to be in storage until as late as July 2008, when it will replace the operational GOES East at its end-of-life. To summarize, the earliest operational date of GOES-N is July 2005, while the latest date of first GOES-N operation is July 2008; the most probable operational date is somewhere between these two dates.
Transition Concept
A phased transition is planned from EMWIN-I to EMWIN-N, barring premature satellite failures:
NESDIS stores spare satellites in geosynchronous orbit over
the
NESDIS’s Office of Satellite Operations (OSO) schedules a nominal 10-15 day period each year in June for the purpose of verifying the health of the stored satellites. During these periods, the EMWIN-N datastream can be broadcast through the satellite. OSO testing activities do not affect or interfere with the EMWIN signal. These periods will provide users and vendors the opportunity to test their systems in the new operational environment.
The intention is to minimize user impact by retaining the current frequency and modulation for all operational broadcasts from the GOES I/M satellites. Test broadcasts from the I/M satellites will retain the current frequency but the new BPSK modulation. All broadcasts (test and operational) from the GOES N/P satellites will use the new frequency and new modulation. When GOES N first becomes operational, one satellite from the I/M series and one satellite from the N/P series will be the operational CONUS constellation. During that period, EMWIN will be broadcast at two different frequencies and modulations.
The Fourth Phase will be the broadcast of the EMWIN-N datastream from the GOES-N satellite, currently planned as GOES East. The Fifth, and final, Phase will be the broadcast of the EMWIN-N datastream through the GOES West satellite.
Initially the broadcast frequency remains the same so there should be no change to the receiving frequency. Once switched to GOES N-series spacecraft, the receiver will need to be “tuned” to the new frequency. If this is not possible due to the characteristics of a specific manufacturer’s receiver, then a new receiver may be necessary. This is highly dependant on current user hardware specifics and design details of the receivers of various vendors.
The Transition Concept is enabled by the flexibility of the new EMWIN receiver system. The new receiver system uses a completely different approach than the current EMWIN receiver systems. The new EMWIN receiver system is based on a custom software application residing in a commercial/off-the-shelf personal computer with an analog/digital sound card that will replace the custom hardware demodulator module of the current EMWIN systems. The EMWIN functional schematic is shown in Figure 1 below.
Assuming the user’s existing PC has a capable sound
card and sufficient computing resources, the cost implications to the user are
minimized. In the information technology
world, relying on capabilities of any existing systems, which are more than 2-3
years old, has some risk. Processors
need to be Pentium-class machines. Sound
card functionality has changed exponentially in the past 3-5 years, so the
assumption should be to upgrade the hardware.
The current minimum PC available on the commercial market is a 1.0 GHz
Pentium processor with 128 MB memory and a 20 GB hard disk operating Windows
NT/2000/XP. This processor will utilize
20 to 25% of processing to service the custom software. The analog/digital sound card used in the
development was able to accommodate a sample rate of 96 KHz with an analog
bandwidth of more than 46 KHz. The
development system used an M-Audio 2496 Audiophile series card.
Figure 1. EMWIN Functional Schematic
We believe the new software required for demodulation
of the information received from the sound card will not add a significant
volume to the existing software. The PC
minimum requirements will be much more heavily dependent on the EMWIN software
and storage requirements than on the changes to the system caused by the change
in the demodulation and FEC.
All users will need to make a change to their front-end receive equipment to accommodate the frequency change between EMWIN-I and EMWIN-N, with complexity ranging from a receiver crystal change or re-tuning, to receiver replacement, depending on the flexibility and adaptability of their current units.
The custom software will be a variation of the software originally created for use in the NOAA GOES Low-Rate Information Transmission (LRIT) system. Additional information on LRIT can be found at:
The variation is the addition of software to de-modulate the existing Frequency Shift Keying (FSK) signal to the existing software supporting the new EMWIN-N Binary Phase Shift Keying (BPSK) modulation. Switching between BPSK and FSK will be by keyboard or mouse input. Both the current LRIT system and the EMWIN-N will use the same Forward Error Correction technique, R-S Convolutional.
The Transition Concept is based on the expectation that industry, using NOAA-provided technical information, will produce commercially available receiver systems in a timely manner for the user community. The ability of the new receiver system to operate in either the current or the new environments makes it possible to provide a lengthy transition period without dedicating the use of an additional satellite to emulate the GOES-N era data stream solely for test and evaluation purposes. It is expected the new systems will be placed in service as they are acquired which will provide an extended period of operational use. The annual broadcast of EMWIN-N datastream from a normally stored satellite will provide opportunities for users to verify their systems will continue to perform normally when receiving the broadcast from the future GOES N-series satellites.
GOES-8 and -9 are now located in the Central Pacific, at 166 East and 155 East respectively, in view of the West coast, Hawaii, and are under the control of NOAA’s Fairbanks (Alaska) Command and Data Acquisition Station (FCDAS). Their imaging and sounding abilities are greatly reduced, but their communications capabilities are fully functional. These satellites can provide opportunities for vendors to test their systems at any time of the year with a live EMWIN (-I or –N, but not both simultaneously) datastream upon a request to the NESDIS Office of Satellite Operations.
If requested, and if:
1) the basic attitude control functions of the satellites continue to
operate; 2) the communication functions of the satellites continue to operate;
and 3) no other higher priorities arise, then the broadcasts from GOES-8 and 9
can continue until the lack of fuel to support North-South maneuvers and the
inevitable inclination growth (>3 degrees) makes them impractical for EMWIN
operations … sometime in 2006 for GOES-8 and 2007 for GOES-9.
Assuming users install the new systems, they will be
able to operate them in either the “FSK No FEC” mode (current EMWIN-I) or in
the “BPSK with FEC” mode (GOES N EMWIN-N) by changing the configuration of the
software driver. Thus the users can use
the new systems to receive the current EMWIN-I broadcasts, testing that their
systems operate correctly. When the
GOES-N broadcast is available, they can reconfigure the software driver, change
the frequency, re-point the antenna, and receive EMWIN-N from GOES-N, verifying
their systems work in the GOES-N mode as well.
The footprints for the satellite constellation are provided in Appendix 2.
Transition Activities
Transition activities include:
q Receiver system development, test, evaluation and acceptance
q NWS dissemination of transition plan and information to customers and vendors
q Vendors provide new systems to market
q User transition to new systems
q GOES-N operational
The receiver system test and evaluation phase commenced with the contract award for a prototype receiver system compatible with the planned frequency, power level, and formats required for EMWIN-N reception. The vendor will deliver a dual demodulation (FSK and BPSK) receiver system capable of operating in either current or planned operational modes for EMWIN. The desired demodulation will be selected by a simple keystroke or mouse click configuration change. The detailed EMWIN Transition Schedule is in the Milestone Section below, and a summary of the Technical Characteristics is found in the Users Manual.
The receiver system development and evaluation activities start with contract award, with expected tested prototype receiver system available by November 2003. NESDIS will provide a simulated broadcast of EMWIN-N data streams using GOES-N power levels, modulation, and format. The vendor will be responsible for demonstrating the proposed solution provides a level of service consistent with the current EMWIN-I broadcast. This activity ends with acceptance of the demonstrated capability by NESDIS Office of Systems Development (OSD) Ground Systems Division and NWS Chief Information Officer (CIO).
The NWS will continue to
disseminate transition information as provided by NESDIS and provide customer
outreach support to the EMWIN user community.
The NWS will ensure timely EMWIN transition updates, technical
information and current FAQs are posted on the EMWIN
home page:
Information messages will
also be made available to the user community and vendors through the EMWIN
operational broadcast. The NWS will also respond to the user community on all
data and transition schedule issues.
NESDIS will continue to provide technical support to the NWS so the NWS
can continue its coordination with receiver system vendors.
User transition activities span both the development of EMWIN-N receiver systems and the purchase and installation of those receiver systems by EMWIN users. NWS will continue to notify current and potential users of the necessity to have new equipment prior to the switchover to GOES-N operations. The method of notification is at the discretion of NWS and is expected to include means such as direct communication with current customers, broadcast messages via the Internet, and through NWS publications.
The user will install a new system or reconfigure their existing system by removing the existing demodulator, re-connecting the RF output to the IF, if the IF is a separate component, and then to the PC sound card input port, and configuring the new sound card driver software module (.dll) using the PC keyboard. The user will re-point the receiving system antenna to GOES-11 and begin to receive the EMWIN datastream: -I or -N at the EMWIN-I frequency.
The point of contact for the
arrangement of test periods using the Pacific constellation will be in NESDIS
OSD. The current Point of Contact is:
Angelo Wade, E/OSD, (301) 457 5210 x122.
NESDIS OSD will accept requests based on an oral, E-mail, or written
request. A written test plan and
schedule will be required from the manufacturer, and a minimum 2-weeks
notice. There will be no costs to the
manufacturer. All requests are subject
to deferral for spacecraft or National emergencies.
The vendor’s design of the new receiver system will involve
new software, at least the AVTEK .dll, and probably
new hardware, an IF converter. The
majority of the testing plan should be executed in the vendor’s
facilities. The only need for testing
using the a satellite transmission path should be a validation that the
end-to-end system functions properly.
Vendors and customers will have the opportunity to test and validate their new equipment using current EMWIN broadcasts and, periodically, validate that their new equipment operates satisfactorily in the EMWIN-N mode by ingesting the annual transmissions from the normally-stored satellites either emulating GOES-N broadcasts or actually broadcasting from the normally-stored GOES-N satellite following its launch and checkout.
If vendors are able to supply the first new systems in time for the June 2004 test period, the User Transition Phase could last from June 2004 to as late as July 2008.
NOAA Responsibilities
During the EMWIN transition period, the following responsibilities are planned:
q NESDIS/OSD
§ Develop this transition plan
§ Award prototype receiver systems demonstration contract
§ Evaluate/certify demonstration system performance
§ Coordinate with NWS on activities and progress
§ Assist NWS on future receiver systems vendor coordination
§ Participate in EMWIN conferences,
§ Establishment of dates for transition and cutover in coordination with NWS
q NWS/CIO Office
§ Notify customers and vendors of the start of transition activities
§ Issue periodic user notification messages
§ Participate in EMWIN conferences
§ Provision of communications access circuit to WCDAS
§
Coordination of dates for transition and
cutover.
The Point of Contact for users and vendors is William
Johnson, NWS/OCIO1, (301) 713 0863.
NESDIS will designate a Technical Point of Contact who will assist the
NWS by responding to tasking by the NWS when necessary to answer vendor
inquiries that cannot be answered by the NWS.
There was a single identified risk: Failure to demonstrate the successful prototype receiver system solution by the end of October 2003. The prototype receiver system was not completed in time to meet this milestone and is now encroaching on the time required by vendors and EMWIN customers to implement, test, and place into operation new equipment. NESDIS has confidence the demonstration receiver system will meet the requirements because of prior technical coordination with the contractor and the contractor’s past experience with the similar LRIT systems. NESDIS fully recognizes the impact of the milestone slip and is working with the NWS to recover from the impact of the slip.
Milestones
Milestones for the EMWIN transition originally agreed to by NESDIS and NWS are:
1.
2.
3.
4.
5.
6.
7.
WCDAS
8. April-July 2004 Vendors
test new workstation (from West Coast or
9.
10. Fall-Winter 2004 Deployment of new workstations to Users
11. July 2005 Transition GOES-East to the EMWIN-N
12. March 2006 Transition GOES-West to the new EMWIN-O
The current status of the milestones for the EMWIN transition is as follows:
1.
2.
3.
4.
5.
6.
__________S/S_____________________ _______S/S____________________
Richard G. Reynolds Larry Curran
NESDIS NWS
E/OSD W/CIO1
Appendix
1
EMWIN
Acronyms
ASM Attached
Synchronization Marker
BER Bit
Error Rate
bps bits
per second
BPSK Binary
Phase Shift Key
CADU Channel
Data Access Units
CCSDS Consultative
Committee for Space Data Systems
dB decibel
dBmi Decibels
milliwatts isotropic, meaning referenced to a
zero-gain antenna
EIRP Effective
Isotropic Radiated Power
EMWIN Emergency
Manager’s Weather Information Network (NOAA/NWS)
EMWIN-I EMWIN
as transponded through the GOES-I/M series
spacecraft, with associated frequency and modulation characteristics
EMWIN-N EMWIN
as transponded through the GOES N-Series spacecraft,
with associated frequency, modulation, and coding characteristics
FCDAS
FEC Forward
Error-Correcting Code
FSK Frequency
Shift Key
G/T gain-to-noise
temperature ratio
GOES Geostationary
Operational Environmental Satellite (NOAA/NESDIS)
GOES-I/M A
series of GOES spacecraft launched between 1994 and 2001, and operationally
designated GOES-8/-12
GOES N-series The next generation GOES spacecraft (GOES-N, -O, and –P), with the
first launch planned in December 2004
ITU International
Telecommunications
LRIT Low-rate
Information Transmission
NESDIS National
Environmental Satellite, Data, and Information Service (NOAA)
NOAA National
Oceanic and Atmospheric Administration
NWS National
Weather Service (NOAA)
OSD Office
of Systems Development (NOAA/NESDIS)
R-S Reed-Solomon
WCDAS Wallops
(
WEFAX Weather
Facsimile
Appendix
2
Footprint
of GOES satellite CONUS constellation
Pacific Constellation