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FengYun-1D
The FY-1D spacecraft are upgraded versions of the FY-1B satellite. A major effort has been made to improve the S/C reliability. The satellite structure is a hexahedron with body dimensions of 1.42 m x 1.42 m x 1.2 m. The deployed length of the S/C is 10.5 m. There are two solar panels, each with a total collecting area of 9.58 m2 providing power of 250 W. The S/C is three-axis stabilized with a pointing accuracy of 0.4°. Two MVISR instruments (one redundant) are mounted on the nadir-facing side of the S/C. The S/C mass is 954 kg, the S/C design life is two years.
RF communication: The High Resolution Picture Transmission mode of FY-1D is named CHRPT (China HRPT or simply CHRPT), implemented in S-band. The data rate of CHRPT is 1.3308 Mbit/s, the modulation is BPSK/Bi-phase,m the polarization is right hand circular, the EIRP = 39.4 dbm. The transmission frequency is 1700.5 MHz. The data format is very similar to that of HRPT of the NOAA satellites. The on-board data storage capacity is increased to 300 minutes of data take (compared to 60 minutes on FY-1A/1B). This offers the provision of a parallel (to CHRPT) low-rate data stream, once per day, of four selected channels with reduced resolution (3.1 km) data, the low-rate transmission rate is 88.72 kbit/s. The low-rate data is referred to as DGPT (Delayed Global Picture Transmission), while the ten-channel data with 1.1 km resolution from anywhere in the world is referred to as DLPT (Delayed Local Picture Transmission). There is no support provided for APT mode communications.
A launch of FY-1D took place on May 15, 2002 from the Taiyuan Satellite Launch Center, along with Haiyang-1 (Ocean-1) on a LM-4B launch vehicle.
Orbit: Sun-synchronous polar orbit, altitude = 863 km, inclination = 98.79?, period = 102.3 minutes, eccentricity t0.005, the repeat period is 12 days. The local equatorial crossing time is for FY-1D is around 7 and 9 AM, respectively, on the descending node.
Some application examples of FY-1D data: Drought monitoring, snow cover and snow disaster monitoring, flood monitoring, forest and grassland fire monitoring, dust storm monitoring, sea ice monitoring, etc.
Basic characteristics (MVISR):
Band No |
Spectral Range (µm) |
Primary use of data: |
1 |
0.58 - 0.68 (VIS) |
Daytime clouds, ice and snow, vegetation |
2 |
0.84 - 0.89 (VNIR) |
Daytime clouds, vegetation, water |
3 |
3.55 - 3.93 (MWIR) |
Heat source, night cloud |
4 |
10.3 - 11.3 (TIR) |
SST, day/night clouds |
5 |
11.5 - 12.5 (TIR) |
SST, day/night clouds |
6 |
1.58 - 1.64 (SWIR) |
Soil humidity, provision of ice/snow cover distinguishing capability |
7 |
0.43 - 0.48 (VIS) |
Ocean color |
8 |
0.48 - 0.53 (VIS) |
Ocean color |
9 |
0.53 - 0.58 (VIS) |
Ocean color |
10 |
0.90 - 0.965 (VNIR) |
Water vapor |