As future environmental satellites improve their monitoring and observing capabilities, they will produce far more data than the current satellite series. The geostationary environmental satellite constellation will employ new downlink frequency allocations, larger bandwidths, and faster data rates. Environmental data users must employ new field terminal receivers unique to that particular broadcast service.
Joint Polar-orbiting Satellite System (JPSS)
The JPSS-1 satellite will be based on the Suomi NPP satellite. NASA launched the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP), on Oct. 28, 2011. On January 24, 2012, NPP was renamed Suomi National Polar-orbiting Partnership, or Suomi NPP. NASA renamed NPP in honor of the late Verner E. Suomi, a meteorologist at the University of Wisconsin who is recognized widely as "the father of satellite meteorology." The SNPP mission, launched in October 2011, is the bridge between the NASA Earth Observing System (EOS), NOAA POES constellation and the future JPSS satellites. JPSS is the civilian component of the former NPOESS program managed by NOAA.
The JPSS will fulfill NOAA’s long-standing obligation to the Initial Joint Polar-orbiting Satellite System (IJPS), an agreement between NOAA and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) to collect and exchange environmental data from the polar orbit to users in support of operational meteorological and environmental forecasting and global climate monitoring, the Joint Transition Activities, and the future Joint Polar System (JPS).
The JPSS will succeed NOAA’s POES satellites and ground systems by leveraging investments made in NOAA POES, NASA’s Earth Observing System (EOS), and the SNPP to maintain continuity of global, operational, space-based observations. The JPSS will deliver an operational polar-orbiting satellite system that will exceed NOAA POES capabilities in terms of quality, volume, accuracy and timeliness of environmental data products and services. The JPSS system will consist of satellites in the 1330 Local Time of the Ascending Node (LTAN). The JPSS-1 mission is currently scheduled for launch in December 2016, and the JPSS-2 mission in November 2021.
Significant progress has been made with the SNPP satellite launched on October 28, 2011. The five SNPP instruments trace their heritage to instruments on NASA's Terra, Aqua and Aura missions, on NOAA's POES spacecraft, and on DOD's Defense Meteorological Satellite Program (DMSP). The spacecraft directly transmits Stored Mission Data (SMD) at 300 Mbps primarily to a receiving station in Svalbard, Norway, and provides continuous direct broadcast of real-time sensor data. Mission data is routed from Svalbard to the United States. SNPP SMD may also be broadcast to ground stations at Fairbanks, Alaska and McMurdo, Antarctica.
The five instruments on the SNPP satellite are: The Advanced Technology Microwave Sounder (ATMS), which is a 22-channel passive microwave radiometer, to provide data for global models of temperature and moisture profiles that meteorologists enter into weather forecasting models. The Cross-track Infrared Sounder (CrIS)Michelson interferometer, monitors and derives characteristics of the atmosphere, such as moisture and pressure that are used to produce improvements in both short-and-long term weather forecasting. The Ozone Mapping and Profiler Suite (OMPS) continues the long-term continuous data record of ozone measurements from space. The Visible Infrared Imaging Radiometer Suite (VIIRS) is a 22-band radiometer that collects visible and infrared views of Earth's dynamic surface processes, such as wildfires, land changes, ice movement, and measures atmospheric and oceanic properties, including clouds and sea surface temperatures. The Clouds and the Earth's Radiant Energy System (CERES) is a 3-channel radiometer that measures reflected solar radiation, emitted terrestrial radiation, and total radiation, to monitor the natural and anthropogenic effects on the Earth's total thermal radiation budget.
Partnerships are key to the ability to provide continuous polar-orbiting measurements. NOAA, NASA, and the DOD/Air Force have a productive relationship in polar observations; sharing data, coordinating user needs, and operating satellites. This cooperative relationship is essential and will continue. Likewise, partnerships with Europe through EUMETSAT will continue to be a strong part of the polar-orbiting constellation.
Figure 1: SNPP/JPSS Direct Readout Continuity of Services.
Once operational, SNPP and JPSS-1 will replace the current POES constellation. The POES spacecraft revolutionized the way in which we observe and predict the weather. We are evolving the existing “weather” satellites into an integrated environmental observing system by expanding our capabilities to observe, assess, and predict the total Earth system. Data from advanced sensors will be available faster than today significantly improving NOAA National Weather Service (NWS) forecasts and serving data continuity requirements for improved global climate change assessment and prediction.
The JPSS is comprised of satellite missions, and ground and space components for command, control and communications, and product processing for making data products available to users. The satellite missions include JPSS-1, JPSS-2, Free Flyer-1, and SNPP. JPSS will provide data to the Direct Readout community through High Rate Data (HRD) broadcasts. Figure 1 provides the direct readout continuity of services. Budget constraints led to the removal of the Low Rate Data (LRD) broadcast from JPSS-1+2. NOAA would consider funding from an outside party to pay for hosting LRD on JPSS-2.
The JPSS Ground System is comprised of command and data acquisition sites (ground stations); communication systems for transmission of commands, telemetry, and Stored Mission Data (SMD); mission management centers, and product processing and distribution centers. Enterprise synergies across missions are planned for similar ground system functions. For redundancy, an interface to the space-based Tracking and Data Relay Satellite System (TDRSS) is provided. Ground stations are located at Svalbard, Norway; Fairbanks, AK; and McMurdo, Antarctica. Primary mission management, product processing, and distribution are located at the NOAA Satellite Operations Facility (NSOF) in Suitland, Maryland; alternate processing center operations are located at the Vertex Center in Fairmont, WV.
Real-time JPSS data products will be delivered to the NOAA Comprehensive Large Array-data Stewardship System (CLASS) and the National Environmental Satellite Data, and Information Service (NESDIS) Environmental Satellite Processing Center (ESPC) for additional processing and distribution to users. JPSS data products will be available to the National Climatic Data Center (NCDC) Climate Data Record (CDR) Program via CLASS.
Direct Broadcast Services
In addition to the space-to-ground transmission of stored mission data (SMD) from each satellite, the JPSS-1+2 will provide a High Rate Data (HRD) direct broadcast (similar to SNPP). Figures 2+3 provide the planned RF links for the JPSS missions.
The direct broadcast/real-time field terminals will be capable of processing Raw Data Records (RDRs) into Environmental Data Records (EDRs) by using a JPSS/Field Terminal Segment (FTS) open source processing software package using commercial-off-the-shelf systems. NOAA, though the JPSS/FTS program, will distribute the non-proprietary field terminal software, software changes, and program updates. The direct broadcast X-band community supported by NOAA’s Cooperative Institute for Meteorological Satellite Studies (CIMSS) will still be able to acquire tailored software directly from CIMSS.
Figure 2: SNPP Direct Readout Configuration.
Figure 3: JPSS-1+2 Direct Readout Configuration.
The CIMSS developed a capability to support NOAA's SNPP/JPSS direct broadcast users in the real-time regional applications of ATMS, CrIS, and VIIRS data. CIMSS released an independent processing package for SNPP, based on the Interface Data Processing Segment (IDPS) operational versions of the VIIRS, CrIS, and ATMS algorithms implemented by Raytheon in the Algorithm Development Library (ADL) version 3.0.
The initial version of the SNPP package called "Community Satellite Processing Package (CSPP)" is a public release. The first version contains VIIRS SDR and EDR algorithms only; CrIS and ATMS support will be added later. The CSPP project is specifically to support NOAA direct readout users in making the transition from POES to SNPP and subsequently to JPSS. CSPP is a stand-alone package for 64-bit Intel Linux platforms, and packaged similarly to IMAPP. It runs from the Linux command line, and does not require other processing framework to make installation friendly and straight forward for future upgrade and maintenance.
Features and Goals of SNPP/JPSS component of CSPP are further summarized below:
The High Rate Data (HRD) broadcast will be a full resolution data set (up to the 15 Mbps data rate limit) containing sensor data necessary to generate data products and is intended to support users at fixed, regional hubs. A complete set of auxiliary/ancillary data will also be available at an on-line server for field terminal real-time processing. The following table provides the HRD link parameters of interest:
|Data Flow||Center Frequency||Data Rate||Coverage (half cone angle)||BER||PCM Format||
(255,223) RS, I=4
Rate ½ length 7
Table 1: HRD Direct Readout Link Parameters
NOAA will be introducing a new advanced imager in 2015 with significantly improved performance to the current GOES satellites. The new Advanced Baseline Imager (ABI) will be carried aboard the GOES-R Series. The ABI will have 16 spectral bands that will provide a host of new capabilities and products for NOAA and its user community. The 0.59-0.69 micron visible band will have 0.5 km resolution. Bands centered at 0.47, 0.865, and 1.61 micron will have 1.0 km resolution with all other bands being 2.0 km resolution. The new imager scanning rate will be significantly increased to provide a full disk every 5 minutes (Mode-4), or 4 full disks per hour (one every 15 minutes) plus 12 CONUS scans per hour (one every 5-minutes) and 120 mesoscale images per hour with up to two mesoscale regions being observed in each 15 minute interval (Mode 3).
The ABI will provide key performance parameters for cloud and moisture imagery for Full Disk, Continental United States (CONUS), and Mesoscale coverage for monitoring, forecasting and severe weather warning. Additional instruments include Space Environment In-Situ Suite (SEISS), Extreme Ultraviolet Sensor/X-Ray Sensor Irradiance Sensors (EXIS), Solar Ultraviolet Imager (SUVI), Magnetometer (MAG), and Geostationary Lightning Mapper (GLM).
The GOES-R instrument raw data downlink is expected to be approximately 75 Mbps. The corresponding entire Level 1b data stream GOES Re-Broadcast (GRB) will be on the order of 31 Mbps, in a dual circularly polarized data stream. The content distributed by GRB will be the full set of level 1b products, including data from all ABI channels and the other GOES-R instruments (GLM, MAG, SEISS, SUVI, EXIS, and Magnetometer).
The GOES-R spacecraft communication system will be significantly different from the previous GOES satellites, driving changes to the direct-receive data sites and the introduction of new data formatting. Because of the large data rate the GVAR format will no longer be used.
The GOES-R Program Office (GPO) has developed a Government Reference Architecture that provides a workable solution to the GOES-R GRB requirements.
GOES users must upgrade or acquire new antenna and receiver hardware, and acquire processing systems in order to receive the higher volume of GOES-R data via GRB.
To minimize the impact on the user, the GRB will continue to be transmitted in L-band, but use an expanded bandwidth (1681 MHz -1692 MHz). Emergency Managers Weather Information Network (EMWIN) has been combined with Low Rate Information Transmission (LRIT) and the separate EMWIN transponder eliminated from GOES-R. The new service will be known as High Rate Information Transmission (HRIT)/EMWIN. On GOES-R, the Data Collection Platform Report (DCPR) service will be operated in the 1679 MHz to 1680 MHz range (see Table 3).
|Service||Current Frequency Spectrum||Current Data Rate||Future Frequency Spectrum||Future Data Rate|
|GVAR/GRB||1685.7 MHz||2.11 mbps||1686.6 MHz||31 Mbps|
|LRIT –> HRIT||1691 MHz||128 kbps||1694.1 MHz||400 kbps*|
|1692.7 MHz||9.6 kbps||1694.1 MHz||400 kbps*|
|1679.9 MHz||300/1200 bps|
*Note: HRIT and EMWIN will have a combined service with a data rate of 400 kbps.
Table 3 - Impact on Transmission Frequencies/Data Rates for GOES-R
To fit within the available bandwidth of 11 MHz (centered around 1686.6 MHz), the GRB service will employ dual polarization, having two signals: one right circular and the other left circular polarization. Users will need new field terminal equipment to receive GRB as it replaces GVAR. The GOES-R program investigated providing an interim service that would partially emulate the GVAR, but determined that system would be best served by conducting a controlled system phaseover to the GRB service. The main factor contributing to this decision was the reliance on previous generation satellites and ground equipment remaining available to support the broadcast, coupled with the complexity and risk of fielding two simultaneous services. While there are no plans for a simplified GRB data format during the transitional period prior to GOES-R operations, a key feature in the Ground Segment Project transition plan is maintaining continuous contact with the user communities to ensure they are fully aware of the requirements needed to be able to receive and process the larger and faster GRB data stream. At the Direct Readout Conference held in April 2011, users requested NOAA to develop a minimum system configuration for GRB reception to assist GVAR users in planning their transition.
The GRB transmission format is DVB-S2, but some details of the modulation are still being defined. The intent is to take advantage of standard formats and technologies. The GRB processed instrument data source will be packetized compliant with Consultative Committee for Space Data Systems (CCSDS) standard 133.0-B-l and will utilize lossless data compression to fit within allocated bandwidth. Data blocking and accompanying header metadata will be used to minimize risk of loss due to link errors and allow for user verification of data integrity.
GRB’s dual polarization format represents a complete format change from GVAR, driven by the improved temporal and spatial measurement characteristics of the new instruments. This quantum leap in instrument capability and potential for vastly improved user products necessitates the complete transition of users from GVAR to GRB. Field terminals and user facilities must evolve as GOES-R’s capabilities are developed, launched, tested and placed into operational service.
A GRB simulator is being developed and five of them are in production for 2013. The intent is to provide the simulator to the vendors that manufacture GRB receivers in order to verify GRB receive system compatibility with the GRB transmission. Details on how vendors of GRB receivers can request the simulator are under development.
The simulators will be used for: • On-site testing of user ingest and data handling systems, such as GRB field terminal sites. • Simulation of GRB downlink functionality by generating Consultative Committee for Space Data Systems (CCSDS) formatted GRB output data based on user-defined scenarios, test patterns, and proxy data files.
More details can be found on the GOES-R website at: www.goes-r.gov/users/grb.html.
The direct readout services from NOAA spacecraft are changing significantly . A summary of the spacecraft effects and field terminal changes is listed below:
Based on the typical life expectancy of the satellites, we would expect APT and HRPT will be available on at least one POES satellite until about 2017 - 2019.
APT is not available on NOAA satellites after NOAA-19.
The HRPT service will not be replace with an L-band service on JPSS-2 satellite and beyond.
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