DBCP-XXI/Doc. 8.6.2, p. 1
WORLD METEOROLOGICAL ORGANIZATION______ / INTERGOVERNMENTAL OCEANOGRAPHIC COMMISSION (OF UNESCO)
______
DATA BUOY COOPERATION PANEL
TWENTY-FIRST SESSION
BUENOS AIRES, ARGENTINA
17-21 OCTOBER 2005 / DBCP-XXI/Doc. 8.6.2
(19.VIII.2005)
ITEM: 8.6.2
ENGLISH ONLY
GTS delays and Argos ground receiving stations
(Submitted by the Technical Coordinator)
Summary and purpose of documentThis documents presents status of Argos data processing ground segment and its impact on GTS delays. It also provides information on plans to eventually improve the system.
ACTION PROPOSED
The panel will be invited to to comment, and particularly make decisions or recommendations, as appropriate on the following topics:
(a)Invite NOAA/NESDIS to provide up to date information regarding developments for replacement of Lannion at Barrow, and possible tests at Svalbard;
(b)Invite UK and South African representatives to provide information on status and future plans to eventually establish an FTP link between Malvinas/Falkland Islands and Service Argos for Argos TIP data.
(c)While multi-satellite service is free of charge, consider how ADS distribution of additional data sets should be charged, and make appropriate recommendations to the JTA;
(d)Note current extension of Argos regional network and its impact on timeliness of buoy data.
Decide on possible further action required regarding this issue.
______
DISCUSSION
1) Status of Argos ground segment
1.1) Regional network
CLS and Service Argos Inc. pursued their efforts to increase the number of receiving stations able to provide TIP data sets from the NOAA satellites. Two new stations joined the Argos network since last DBCP session, Chennai, October 2004. They are in Indonesia (Bali) and India (Hyderabad).
There are currently 44 stations (figures 1 & 2) delivering real time (TIP) data sets to CLS and Service Argos Inc. Most of them process data from NOAA-16, NOAA-17, NOAA-15, NOAA-14 and NOAA-12, so good throughput times for delivery of results can be maintained.
Service Argos has plans to install antenna in Gabon.
Figure 1: Argos network of regional receiving stations.
Antennas / Sigle / Country / Operator / Possible satellites1 / Buenos Aires * / BA / Argentina / INTA / N12, N14, N15, N16, N17 / *
2 / Casey / CA / Australia (Antarctica) / BOM / N12, N14, N15, N16,
3 / Cayenne / CY / France (Guyana) / IRD / N12, N14, N15, N16, N17
4 / Darwin / DA / Australia / BOM / N12, N14, N15, N16, N17
5 / Gilmore / GC / USA / NOAA/NESDIS / N12, N14, N15, N16, N17
6 / Halifax / HF / Canada / Can. Coast Guard / N12, N14, N15, N16, N17
7 / Hatoyama / HA / Japan / NASDA/EOC / N12, N14, N15, N16,
8 / Hawaï / HW / USA / NOAA/NWS / N12, , N15, N16, N17
9 / Ile de la Réunion / RN / France (Reunion Island) / Météo France / N12, N14, , N16,
10 / Ile de la Réunion / RE / France (Reunion Island) / IRD / N12, N14, N15, N16, N17
11 / Lannion / WE / France / Météo France / , , N15, N16, N17
12 / Las Palmas / LP / Canaries Island / Univ. Las Palmas / N12, N14, N15, N16, , N18
13 / Melbourne / ME / Australia / BOM / N12, N14, N15, N16, N17, N18
14 / Miami / MI / USA / NOAA/AOML / N12, N14, N15, N16, N17
15 / Noumea / NO / France (New Caledonia) / IRD / N12, N14, , N16,
16 / Oslo / OS / Norway / NMI / N12, N14, N15, N16, N17
17 / Perth / PE / Australia / BOM / N12, N14, N15, N16, N17, N18
18 / Punta Arenas / PA / Chile / meteo Chile / N12, N14,N15 , ,
19 / Santiago / CH / Chile / meteo Chile / N12, N14,N15 , ,
20 / Singapore / SG / Singapore / SMM / N12, N14, N15, N16, N17
21 / Tahiti / TA / France (Tahiti) / Météo France / N12, , N15, N16, N17, N18
22 / Tromsoe / ST / Norway / KSAT / N12, N14, N15, N16, N17
23 / Wallops / WI / USA / NOAA/NESDIS / N12, N14, N15, N16, N17
24 / Wellington / NZ / New-Zeland / Met Office / , N14, N15, N16, N17
25 / Athenes / AT / Greece / NCMR / N12, N14, N15, N16, N17, N18
26 / Aussaguel / AU / France / CLS / N12, N14, N15, N16, N17
27 / Bali / BL / Indonesia / PT CLS / N12, N14, N15, N16, N17, N18
28 / Bitung / BI / Indonesia / PT CLS / N12, N14, N15, N16, N17
29 / Cape Town / SA / South Africa / CLS/SAWB / N12, N14, N15, N16, N17, N18
30 / Helsinki / HL / Finland / CLS / N12, N14, N15, N16, N17, N18
31 / Largo / LA / USA / SAI / N12, N14, N15, N16, N17
32 / Las Palmas / CN / Canaries Island / CLS / N12, N14, N15, N16, N17, N18
33 / Lima / PR / Peru / CLS Perù / N12, N14, N15, N16, N17, N18
34 / Toulouse / RV / France / CLS / N12, N14, N15, N16, N17, N18
35 / Murmansk / RU / Russia / Complex System / N12, N14, N15, N16, , N18
36 / Petropavlosk / PT / Russia / Rybradiov / N12, N14, N15, N16, N17
37 / Tokyo / JM / Japan / Jamstec / N12, N14, N15, N16, N17, N18
38 / Antarctica / AC / Chile / Meteo Chile / N12, N14,N15 , ,
39 / Edmonton / ED / Canada / Envir. Canada / N12, N14, , N16, N17
40 / Fidji / FI / Fidji / FMS / , N14,N15 , ,
41 / Hyderabad / HY / India / ISRO / N12, N14, N15, N16, N17
42 / Monterey / MO / USA / NESDIS/NWS / N12, , N15 , N16, N17
43 / Riyadh / RY / AU / KACST / N12, N14, N15, N16, N17
44 / Sondre / GR / Greenland / DMI / N12, N14, N15, N16, N17
* the only station to locate the satellites when they are situated at a 20° site angle
Antennas under agreement
CLS and subsidiaries antennas
Customer antennas under CLS maintenance contract
Antennas without written agreement ("Best effort")
Figure 2: List of regional receiving stations (S-band antennas).
Malvinas/Falklands IslandsLUT:
UK and South Africa will be invited to report on the current status of establishing data telecommunication link for Argos TIP data from Malvinas/Falklands Islands LUT to the Argos network. UK will be particularly invited to report on the current status of the 64K telecommunication line to the Metoffice headquarters in Exeter and whether appropriate software to transfer Argos TIP data via FTP and through local firewall had been written.
1.2) global network
Global network includes the following two stations:
- Wallops Island, Virginia, USA
- Gilmore Creek, Fairbanks, Alaska, USA
These stations deliver the STIP telemetry from the satellites NOAA-12, NOAA-14, NOAA-15, NOAA-16, NOAA-17 and NOAA-18.
Regarding NOAA-12, only two orbits per day are delivered by NOAA/NESDIS. It is just enough to collect the minimum amount of data from the orbitography Argos beacons required for the processing of the Argos location.
Since the end of 2003, the STIP telemetry from NOAA-14 – the only type of telemetry available for this satellite – is delivered by group of three or four orbits.
Figure 3 shows the global data set (STIP) arrival times at the Toulouse and Largo processing centers. Ideally, one data set should be received every 100 minutes.
Figure 3: global data set (STIP) arrival times at the Toulouse and Largo
Filling the gap for Lannion
Reception and data processing of Stored Tiros Information Processing (STIP) were terminated at Lannion in 2000. DBCP was stressing and demonstrating in the last three years that this had adverse effects on the timeliness of the buoy data distributed on GTS, particularly due to the “blind” orbits. Prior to DBCP-19, NOAA/NESDIS had reviewed the DBCP and JTA participant concerns, coordinated similar requirements from other users and evaluated the cost/benefits of the Lannion, France, and Barrow, Alaska sites. A consolidated requirement for POES “blind” orbit data was presented to NESDIS management for decision and was approved for implementation at the Barrow site. The Argos report to JTA 23 indicated that NOAA/SOCC was taking steps to enhance the facilities at Barrow, Alaska where the necessary equipment exists to download the “blind orbits.”
At DBCP-20, Chennai, October 2004, it was reported that NOAA/SOCC was taking steps to enhance the facilities at Barrow where the necessary equipment exists to download some of the “blind orbits.” However, a report at the OPSCOM 38 in June, 2004 indicated, that software upgrading would be necessary to enable simultaneous reception of HRPT and STIP data at Barrow. The earliest date when funding may be available for this upgrade is October 2006. In the meantime NOAA was interested in testing its equipment in place at Svalbard for risk reduction for the NPOESS mission. NOAA was considering downloading blind orbits for one or both of the operational satellites to accomplish this test.
At the time of writing this report (August 2005),tests were about to be conducted. NOAA is invited to provide more detail at this DBCP session.
2) Argos data delivery times
As far as GTS distribution is concerned, the following delays must be added:
- Period during which observations are stored onboard the buoy before actual data transmission to the satellite, i.e. back-hour delays for recorded observations (platform programming dependant), and time waiting for the satellite to be in view of the buoy (platform position (mainly latitude) and NOAA satellites orbitography dependant);
- Satellite pass duration, as we have to wait for the end of the pass to transfer and process the data set;
- Time taken to transfer data sets to the global processing centers. These include (i) orbital delays (global system only), and (ii) time to transfer the data from the receiving stations to the Argos global processing centres. Most regional data are transferredvia the Internet. The transfer rate is regularly improving.
- Time taken to process the data set by the global processing centers. This is not significant, typically less than 30 seconds.
- GTS data processing at Service Argos;
- GTS bulletins routing delays.
GTS delays for global BUOY reports received at Météo France in July 2005 are given in figure 4 below.It shows that about 30% of the data are received within 1 hour, 50% within 2 hours. Figures 5 to 8 provide information on number of EGOS then EUCOS drifting buoys and upgrades, number of observations, and percentage of observations received within 30 minutes and 2 hours respectively since 2002. Because of better LUT coverage in the region, delays are better in the North Atlantic than for global data. Small reduction of percentage of real time data in the North Atlantic can be explained through increasing distribution of back-hour data which are already delayed at the time of transmission through the Satellites.
Figure 4: GTS delays, BUOY reports received at Météo France, July 2005.
Figure 5: Evolution of average number of EGOS then EUCOS drifting buoys and upgrades since 2002 (source EUCOS)Figure 6: Evolution of average number of observations from EGOS then EUCOS drifting buoys and upgradessince 2002 (source EUCOS)
Figure 7: Evolution of percentage of data arrived within 30 minutes for EGOS then EUCOS drifting buoys and upgrades since 2002 (source EUCOS)
Figure 8: Evolution of percentage of data arrived within 2 hours for EGOS then EUCOS drifting buoys and upgrades since 2002 (source EUCOS)
Loss of Lannion is compensated somewhat through (i) use of multi-satellite service, and (ii) wider extension of the Argos network of regional receiving stations.
Technically, multi-sat service permits to reduce the time a platform is “waiting” before a satellite is in view and the observations actually transmitted.In the new JTA tariff policy, Multi-satellite service is now included to the standard service without any additional charge. However, when multi-satellite service is provided, Argos users are charged for additional volume of information uploaded by them through Service Argos so called Automatic distribution system (ADS). This remains a deterrent for using it. The Panel is invited to consider how ADS distribution of additional data sets should be charged, and make appropriate recommendations to the JTA;
Impact of the extension of the Argos network of regional receiving stations can be estimated thanks to study of Argos throughput times (points 2, 3, and 4 above). CLS, Service Argos throughput times for delivery of results are calculated in terms of the time for the raw Argos data to reach end users. For each message received by the satellite, Service Argos computes the data turnaround time/data availability which is the time elapsed between the recording of the message on board the satellite and processing of the same message by the global processing center.
Table 1 shows the throughput time for stored data result delivery from NOAA-18, NOAA-17, NOAA-16 and NOAA-15.
SatelliteDelivery / NOAA-15, NOAA-16, NOAA-17 & NOAA-181 h / 14 %
1 h 30 / 27 %
2 h / 44 %
2 h 30 / 60 %
4 h / 82 %
Table 1: Stored data availability for satellites NOAA-15, -16, -17 and -18
Table 2 below shows the throughput time for stored data result delivery from NOAA-12 and NOAA-14, two back-up satellites. The delivery of stored data is not done after every download for these two satellites but four satellites are now in table 1, instead of three last year.
SatelliteDelivery / NOAA-12 & NOAA-141 h / 3 %
1 h 30 / 7 %
2 h / 14 %
2 h 30 / 25 %
4 h / 55 %
Table 2: Stored data availability for satellites NOAA-12 and NOAA-14
Table 3 shows the throughput time for real-time result delivery from NOAA-18, NOAA-17, NOAA-16, NOAA-15, NOAA-14 and NOAA-12 and acquired by the 44 HRPT receiving stations.
SatelliteDelivery / NOAA-12, NOAA-14NOAA-15, NOAA-16
NOAA-17 & NOAA-18
10’ / 41 %
15’ / 55 %
30’ / 85 %
45’ / 93 %
Table 3: Real-time data availability
Figure 9 shows percentage of global data received in real time via the 44 regional stations (simulation for September 2005). It shows that there are two ocean regions where less than 30% of the global data are received in real-time, i.e. (i) South Atlantic ocean, near Saint Helena Island, and (ii) SouthEast Pacific Ocean, North and South of Easter Island.Simulations show that for a theoretical network of ocean stations split evenly over the oceans, about 80% of the Argos data would be available through the regional network in near real-time.
Figure 9: Percentage of data received in real time via the 44 regional stations (September 2005)