FY1C & D Information

FY1 C and D Polar Orbiting Spacecraft

FY-1C was launched at 0133Z 10 May 1999 on a CZ-4B vehicle from Taiyuan.
International Designator - 1999-025A
NORAD Catalog Number - 25730
CHRPT Transmission frequency - 1700.4 MHz (actual), 1700.5 MHz (published)

FY-1D was launched at 0150Z 15 May 2002 on a CZ-4B vehicle from Taiyuan.
International Designator - 2002-024B
NORAD Catalog Number - 27431
CHRPT Transmission frequency - 1700.4 MHz

Spacecraft Characteristics

Parameter Item

Orbit altitude 870 Kilometers

Inclination 98.85°

Eccentricity < 0.005

Orbtial period 102.301 minutes

Sensor Multichannel Visible and IR Scan Radiometer (MVISR).
This instrument is a 10 channel sensor with 4 vis, 3 near IR, 1 short IR and 2 long IR.
The IFOV is 1.2 mrad with a nadir resolution of 1.1km

MVISR Characteristics

Channel Wavelength Primary use

1 0.58-0.68 Daytime cloud, ice and snow, vegetation

2 0.84-0.89 Daytime cloud, vegatation, WV calibration

3 3.55-3.95 Night cloud

4 10.3-11.3 SST, day/night cloud

5 11.5-12.5 SST, day/night cloud

6 1.58-1.64 Soil humidity, ice/snow separation

7 0.43-0.48 Ocean colour

8 0.48-0.53 Ocean colour

9 0.53-0.58 Ocean colour

10 0.90-0.985 Water vapor

Spacecraft Characteristics
Parameter	Item
Orbit altitude	870 Kilometers
Inclination	98.85°
Eccentricity	< 0.005
Orbtial period	102.301 minutes
Sensor	Multichannel Visible and IR Scan Radiometer (MVISR). This instrument is a 10 channel sensor with 4 vis, 3 near IR, 1 short IR and 2 long IR. The IFOV is 1.2 mrad with a nadir resolution of 1.1km

MVISR Characteristics
Channel	Wavelength	Primary use
1	0.58-0.68	Daytime cloud, ice and snow, vegetation
2	0.84-0.89	Daytime cloud, vegatation, WV calibration
3	3.55-3.95	Night cloud
4	10.3-11.3	SST, day/night cloud
5	11.5-12.5	SST, day/night cloud
6	1.58-1.64	Soil humidity, ice/snow separation
7	0.43-0.48	Ocean colour
8	0.48-0.53	Ocean colour
9	0.53-0.58	Ocean colour
10	0.90-0.985	Water vapor

FY1-C High Resolution Picture Transmission (CHRPT)
As the MVISR is now 10 channel instead of 5, the bit rate has been increased to 1.3308 Mbps, exactly twice the current HRPT bit rate.
The scan rate is 6 lines/sec with 2048 10 bit words per channel per line plus sync and auxiliary infromation (ie 22,180 10-bit words per line).
        Transmission frequency - 1700.5 MHz (Prime) or 1704.5 MHz (back-up).
        EIRP - +39.4 dBm
        Polarization - Right Hand Circular
        Modulation -PCM/BiPhase-Level/PSK
        Modulation Index - +/-67.5 +/- 7.5 deg;
        Bit Rate -1.3308 Mbps
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CHRPT Frame Format (from CGMS-XXV PRC WP-02)

CHRPT Frame Format

Function Frame
Sync ID Time
Code Telemetry
(Ramp) Telemetry
(Temperature) Black
Body Space
Data Spare Earth
Data Aux
Data

Number
of Words 6 2 4 10 10 60 100 1408 20480 100

**CHRPT Frame Format**
Function	Frame Sync	ID	Time Code	Telemetry (Ramp)	Telemetry (Temperature)	Black Body	Space Data	Spare	Earth Data	Aux Data
Number of Words	6	2	4	10	10	60	100	1408	20480	100

CHRPT Parameters
Number of words in a frame - 222180
Number of channels - 10 with 2048 words per channel
Frame Rate - 6 frames/sec
Number of bits of word - 10 bits /word
Bit Rate - 1.3308 Mbps
Bit Format - Split-phase with a data "1" as high to low level and data "0" as low to high level at the data mid-bit

Detailed CHRPT Frame Format

Function Number of words Word
position Bit number
12345678 90 Meaning

Frame Sync 6 1
2
3
4
5
6 1010000100
0101101111
1101011100
0110011101
1000001111
0010010101 First 60 bits are a 63 bit PN generator, started in the all ones state.
The generator polynominal is X^6 + X^5 + X^2 + X + 1

Identification 2 7 1-4 bit Satellite ID - binary 1100

7 5-10 bit Spare bits

8 Spare word

Time Code 4 9 1-9 bit Binary day count

9 10 bit binary 0

10 1-3 bit binary 101

10 4-10 bit Binary part of millisecind of day count

11-12 1-10 bit Binary part of millisecind of day count

Telemetry (Ramp) 10 13-22 Ramp calibration of 10 channels of MVISR

Telemetry (Temp) 10 23 Temperature of the first stage of radiant cooler A

24 Temperature of the first stage of radiant cooler B

25 Temperature of the second stage of radiant cooler A

26 Temperature of the second stage of radiant cooler B

27 Temperature controlling voltage of the second stage of radiant cooler A

28 Temperature controlling voltage of the second stage of radiant cooler B

29-32 Temperature of sheath of radiometer, one word for each platinium resistance bulb

Reference Black Body 60 33-92 6 sampling words for every channel

Space Data 100 93-192 10 sampling words for every channel

Spare words 1408 193
194
|
1599
1600 0000011101
0000001100
|
1100001101
1101100101 Derived fron the inverted output of a 1023-bit PN sequence provided by a feedback shift register generating the polynominal : X^10 + X^5 + X^2 + X + 1. The generator is started in the all ones state at the beginning of word 7

Earth Data 20480 1601-22080 2048 words for every channel from channel 1 to Channel 10. Each frame contains the data obtained during on Earth scan of the MVISR sensor. The data from the 10 sensor channels of the MVISR are time multiplexed.

Auxiliary Sync 100 22081
22082
|
22179
22180 1111100010
1111110011
|
0111110000
1111001100 Derived fron the non-inverted output of a 1023-bit PN sequence provided by a feedback shift register generating the polynominal: X^10 + X^5 + X^2 + X + 1. The generator is started in the all ones state at the beginning of word 22081

Detailed CHRPT Frame Format
Function	Number of words	Word position	Bit number 12345678 90	Meaning
Frame Sync	6	1 2 3 4 5 6	1010000100 0101101111 1101011100 0110011101 1000001111 0010010101	First 60 bits are a 63 bit PN generator, started in the all ones state. The generator polynominal is X^6 + X^5 + X^2 + X + 1
Identification	2	7	1-4 bit	Satellite ID - binary 1100
		7	5-10 bit	Spare bits
		8		Spare word
Time Code	4	9	1-9 bit	Binary day count
		9	10 bit	binary 0
		10	1-3 bit	binary 101
		10	4-10 bit	Binary part of millisecind of day count
		11-12	1-10 bit	Binary part of millisecind of day count
Telemetry (Ramp)	10	13-22		Ramp calibration of 10 channels of MVISR
Telemetry (Temp)	10	23		Temperature of the first stage of radiant cooler A
		24		Temperature of the first stage of radiant cooler B
		25		Temperature of the second stage of radiant cooler A
		26		Temperature of the second stage of radiant cooler B
		27		Temperature controlling voltage of the second stage of radiant cooler A
		28		Temperature controlling voltage of the second stage of radiant cooler B
		29-32		Temperature of sheath of radiometer, one word for each platinium resistance bulb
Reference Black Body	60	33-92		6 sampling words for every channel
Space Data	100	93-192		10 sampling words for every channel
Spare words	1408	193 194 \| 1599 1600	0000011101 0000001100 \| 1100001101 1101100101	Derived fron the inverted output of a 1023-bit PN sequence provided by a feedback shift register generating the polynominal : X^10 + X^5 + X^2 + X + 1. The generator is started in the all ones state at the beginning of word 7
Earth Data	20480	1601-22080		2048 words for every channel from channel 1 to Channel 10. Each frame contains the data obtained during on Earth scan of the MVISR sensor. The data from the 10 sensor channels of the MVISR are time multiplexed.
Auxiliary Sync	100	22081 22082 \| 22179 22180	1111100010 1111110011 \| 0111110000 1111001100	Derived fron the non-inverted output of a 1023-bit PN sequence provided by a feedback shift register generating the polynominal: X^10 + X^5 + X^2 + X + 1. The generator is started in the all ones state at the beginning of word 22081

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FY-1C Delayed Picture Transmission (CDPT)
. Playback of recorded data of 4 channels at 4 km resolution
. Only available over groundstations in China on 1708.5 MHZ (Prime) or 1695.5 MHz (backup)
. No other details available

Note - There will no APT transmission from FY1 C.