Feng Yun-2 Geostationary Meteorological Satellite

Feng Yun means Wind & Cloud

Last update : 4 January 2005

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
                Visible         Infrared        Water Vapor

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 @

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
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

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)
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)
Frequency       1691.00 MHz
EIRP            +57.5 dBm
Polarisation    Linear, vertical
Modulation      AM/FM
Bandwidth       260 KHz
Bandwidth       1.68 KHz

S-FAX signal characteristics (FY-2A only)
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

Transmission    1-2 minutes for weather chart
duration        3-10 for cloud image

LRIT signal characterists (from FY-2C)
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