Feng Yun-2 Geostationary Meteorological
Satellite
Feng Yun means Wind & Cloud
Last update : 4 January 2005
- CMA new Homepage
- The China Meteorological Administration (CMA) WWW site.
- The CMA National Satellite Meteorological Centre (NSMC) site.
- FY-2 SV data
format (detailed).
Here is some basic information on FY-2 satellites.
The FY2 series of satellites will be operationally similar to GMS with
high resolution stretched VISSR (SV) data (5km IR, 5km WV & 1.25km VIS),
low resolution analog Wefax (discontinued), DCP capability, digital S-band
fax service (CCITT G3) for domestic distribution of charts and imagery (discontinued)
and LRIT.
FY-2A was launched on 10 June 1997 and has been decommissioned and re-orbited.
FY-2B was launched on 25 June 2000 and has been decommissioned and re-located to 123.5° East.
FY-2C was launched on 19 October 2004 and is operational at 105° East.
FY-2 VISSR characteristics
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Visible Infrared Water Vapor
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Wavelength 0.5-1.05 10.5-12.5 6.2-7.5
(micro metre)
Resolution 1.25 Km 5 Km 5 Km
at SSP
FOV 35 140 140
(micro metre)
Scan lines 2500 x 4 2500 2500
per spin
Detector Si photodiode HgCdTe HgCdTe
Noise S/N = 6.5 @ NEDT=0.5-0.65K NEDT=1K
Performance Albedo=2.5% (300K) (360K)
S/N >= 45 @
Albedo=95%
Quantisation 6 bits 8 bits 8 bits
Scan step angle 140 microR (N to S scanning)
per spin
Frame time 30 minutes, 25 scan, 2.5 retrace, 2.5 re-calibration
FY-2 downlink characteristics
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Channel Freq Mod Power BW
S.VISSR 1687.5 MHz BPSK NRZ-M +57 dBm 2 MHz
LRIT 1691.0 MHz BPSK +57 dBm
LR-FAX 1691.0 MHz AM/FM +57 dBm 260 KHz
S-FAX 1699.5 MHz AM/FM +46 dBm 26 KHz
Notes:
LRIT on FY2-C
S-FAX was on FY-2A only
LR-WEFAX ceased on FY-2B in February, 2001
S-VISSR (SV) signal characteristics (FY-2A, B and C)
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Modulation PCM/BPSK, NRZ-M
Bit Rate 660 Kbps, fixed
EIRP +57 +/-1 dBm
Polarisation Linear, vertical
Bandwidth approx 2 MHz
Data volume 329,872 bits per line including SYNC code
Data coding Byte complimenting and PN scrambling
LR-FAX (WEFAX) signal characteristics (FY-2A and B only)
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Frequency 1691.00 MHz
EIRP +57.5 dBm
Polarisation Linear, vertical
Modulation AM/FM
Bandwidth 260 KHz
(Sub-carrier)
Bandwidth 1.68 KHz
(Baseband)
S-FAX signal characteristics (FY-2A only)
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Frequency 1699.50 MHz
EIRP +46 dBm
Polarisation Linear, vertical
Modulation PM-AM/FM
RF deviation - +/-9 KHz
RF bandwidth 26 KHz
Subcarrier PM-AM
Frequency 1.7-1.8 KHz
Bandwidth 300-3400 Hz
Modulation G3 FAX
Coding CCITT T.4
Protocol CCITT T.30
Bit rate 300 bps, CCITT V.21
2400/4800 bps, CCITT V.27 ter
7200/9600 bps, CCITT V.29
Scan density 3.85/7,7 lines/mm
Horizontal 8 pixels/mm
resolution
Transmission 1-2 minutes for weather chart
duration 3-10 for cloud image
LRIT signal characterists (from FY-2C)
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Frequency 1691.0 MHz
EIRP +57.5 dBm
Polarisation Linear, vertical
Modulation 150 kilosymbols per seconds BPSK, unfiltered
Data Format CGMS LRIT and CCSDS compatibility TBC
Mission Specific Implementation TBA