1. Environmental and Disaster Monitoring Small Satellite Constellation
China National Space Administration
May 25, 1999
APRSAF-6

2. FOREWARD
Environment pollution, ecological destruction and natural disasters, seriously affected sustainable development of economy and society in the world.
The application of remote sensing technology for environment protection and disaster mitigation is urgently needed both in China and in the world.
May 25, 1999
APRSAF-6

3. System requirements
May 25, 1999
APRSAF-6

4. System requirements 1) Spatial resolution:
A spatial resolution range of 3 to 100m will be needed.
2） Revisit time：
From hours to many days. But many items need to be observed one or twice a day.
3) Multi-spectral band:
Multi-spectral band with high spectral resolution is needed.
4) All weather and all time observation:
Microwave and infrared remote sensing will be very useful.
5） Large-scale:
Wide swath is needed for most applications.
6) Data storage capability:
To get the image out of receiving area of ground stations.
May 25, 1999
APRSAF-6

5. Small satellite constellation
Satellite is a very effective means in such a system.
Existing satellites can not meet all the requirements.
A set of correlated satellites is necessary to meet the comprehensive requirements.
A small satellite constellation is proposed for monitoring of environment and disaster.
May 25, 1999
APRSAF-6

6. Small satellite constellation
The environmental and disaster monitoring system can be divided into space segment and ground segment.
Space Segment: The first stage (baseline) includes three satellites. And it is expected to expand to the second stage of eight satellites (four optical satellites and four SAR satellites).
Ground Segment: including data receiving and pre-procession system, application system and so on.
May 25, 1999
APRSAF-6

7. Small satellite constellation
May 25, 1999
APRSAF-6

8. Small satellite constellation
The optical satellite:
650km/ 10:45AM sun synchronous orbit . Four satellites are 90°phase distributed in the same orbit plane.
The SAR satellites:
500km/ 6:00AM sun synchronous orbit .
Four satellites are 90°phase distributed in the same orbit plane.
May 25, 1999
APRSAF-6

9. Small satellite constellation
The first stage (baseline) includes three satellites and ground system. The baseline system will be established before 2005.
And it is expected to expand to the second stage of eight satellites. The second stage is proposed to be constructed through international cooperation.
May 25, 1999
APRSAF-6

10. Small satellite constellation
24 hours coverage by 4 optical satellites
24 hours coverage by 1 optical satellite
May 25, 1999
APRSAF-6

11. Small satellite constellation
May 25, 1999
APRSAF-6

12. 1)Wide field multi-spectrum camera (on each optsat)
Payload
1)Wide field multi-spectrum camera (on each optsat)
four bands / 30m resolution /360km*2 swath
2)Infrared scanner (on optsat1)
four IR bands/ 150m~300m resolution /720km swath
3)Hyper-spectrum imager (on optsat2), TBD
4) Data collect system (on all sat)
5) Synthetic aperture radar (on sarsat)
S-band/ 20m resolution/100km swath with incidence angle 25° to 47 °.
6)Possible additional experiment payloads.
Beijing institute of Spacecraft System Engineering
May 25, 1999
APRSAF-6

13. Payload Beijing institute of Spacecraft System Engineering
May 25, 1999
APRSAF-6

14. Payload Beijing institute of Spacecraft System Engineering
May 25, 1999
APRSAF-6

15. Platforms
The platform will be based on the CAST 968 platform which has been used for several small satellites developed in Chinese Academy of Space Technology(CAST)
It includes structures mechanism, attitude and orbit control (AOCS), electronic power supply subsystem (EPSS), TT&C, OBDH, system circuit, etc.
May 25, 1999
APRSAF-6

16. Platforms
May 25, 1999
APRSAF-6

17. Platforms
May 25, 1999
APRSAF-6

18. Configuration of optical satellitev
May 25, 1999
APRSAF-6

19. Configuration of optical satellitev
May 25, 1999
APRSAF-6

20. Configuration of SAR satellitev
May 25, 1999
APRSAF-6

21. Platform of SAR satellitev
May 25, 1999
APRSAF-6

22. Ground Application System
The ground application system is mainly composed of ground receiving and pre-processing system and application system.
Ground receiving and pre-processing system includes ground receiving subsystem, pre-processing subsystem, operation management subsystem and data transmission /communication subsystem.
Application system mainly includes national environment monitoring and forecasting center and national disaster mitigation application center.
May 25, 1999
APRSAF-6

23. Ground receiving and pre-processing system
Three-station network to cover all Chinese territories.
Receiving and real-time recording of large-volume data (the data volume received by three stations will be up to several hundreds Gbytes each day) of multiple satellites, multiple sensors, different data rates.
Real time resolution-decreasing processing of optical and SAR data at each station.
System capacity to generate high production, near real time and high speed all resolution pre-processing products.
Data transmission and communication.
May 25, 1999
APRSAF-6

24. Ground Application System
May 25, 1999
APRSAF-6

25. environment application system
The core of the environment application system is national satellite disaster mitigation and environmental monitoring and forecasting center. It is composed of following four parts:
Environmental remote sensing GIS
Special application subsystem
Environmental remote sensing decision-making support subsystem
Data network environment.
May 25, 1999
APRSAF-6

26. Disaster mitigation application systemv
Disaster mitigation application system of disaster and environment monitoring satellite constellation is composed of image analysis application subsystem and disaster decision-making support subsystem. The core of disaster mitigation application system is national disaster mitigation application system which consisting of disaster information subsystem, information processing subsystem, disaster forecasting and evaluation subsystem, aided decision-making subsystem, emergency management subsystem, disaster study and training subsystem and etc..
May 25, 1999
APRSAF-6

27. System Performance v
The performance of the constellation system(2+1) :
1)Revisit time :
For optical satellite, revisit interval of multi-spectrum CCD camera and infrared scanner will be 48 hours. The average revisiting interval of synthetic aperture radar satellite will be 96 hours..
2) Coverage:
Wide Field Multi-spectrum CCD Camera can cover the globe in two days with 30m resolution. And Infrared Scanner can cover the globe in two days in average with 150m/300m resolution.
May 25, 1999
APRSAF-6

28. System Performance v
The performance of the constellation system(4+4) :
1)Revisit time :
Multi-spectral CCD camera: 24 hours
Infrared scanner :24 hours
Hyper spectral imager: 48 hours
Synthetic aperture radar satellite group: 24 hours.
Average revisiting time: 12 hours by the constellation.
2) Coverage:
CCD camera cover the globe once a day.
Infrared scanner can cover the globe once a day
3) Observation opportunity(at equatorial region):
6:00AM, (SAR); 10:45AM,( CCD,IR,HIS);
6:00PM, (SAR); 10:45PM, (IR).
May 25, 1999
APRSAF-6

29. International cooperation
Common need on environmental protection and disaster mitigation.
Sun synchronous orbit satellites is a global resource .
Construction of the constellation needs very heavy financial support.
Joint construction of the satellite constellation and
sharing of data acquired from the satellites is a very good way.
Will benefit to all the participating countries
Will take an important part in their disaster mitigation and environment protection affairs.
May 25, 1999
APRSAF-6

30. A small satellite constellation can meet most of the requirements.
Conclusion v
Environment protection and disaster mitigation is urgently needed in the world.
A small satellite constellation can meet most of the requirements.
International cooperation is the best way for construction and utilization of this constellation.
This constellation will be very helpful in environment protection and disaster mitigation affairs.
May 25, 1999
APRSAF-6