GISdevelopment.net ---> AARS ---> ACRS 1995 ---> Plenary Session

Outlook on availability of satellite Data and Thai remote Satellite Program

Dr. Suvit Vibulsresth, Ms. Praneet Ditsariyakul
Thailand Remote Sensing Centre
National Research Council Of Thailand

Abstract
After 1987, not only has Thailand Remote Sensing Center ( TRSC) provided the high resolution satellite data worldwide but the development of remote sensing technology also been greatly enhanced. The variety with different correction level is available to fulfill the users` requirement .The synthetic Aperture Radar (SAR) data has also been introduced under the co-operation with Japan for JERS-1 SAR reception , the EC-ASEAN Regional Radar remote sensing ERS-1 project and the global SAR Canada Thailand project in order that the users in this region can make use of the information that the present and future radar satellites can provide. Beside , it is gratifying that Thai government has realized the significance of space technology development and applications. The Thai Remote Sensing small satellite program was recently approved by the cabinet. The Ministry of science , technology and environment through its technical authority in the National Research Council of Thailand will own and operate the small satellite system. This paper will present an outlook on satellite data presently received by NRCT and the system to be operated by NRCT.

1. Introduction
With the capabilities of acquiring and processing multi -sensor data , NRCT has been able to develop remote sensing market successfully . Considering data revenue trends for the past five years starting from calendar year 1990 to1994, the value of products sold has progressively grown from US $ 800,000 in 1990 to US $ 1.6 million in 1994 . This is due to fact that satellite imagery was no longer just use for R & D . It is now a valuable and cost effective solution . however , the existing option sensor could not provide and cost effective solution .However , the existing option sensor could not provide cloud free imagery especially in the rain season therefore SAR data has been introduced to overcome the said limitation .SAR data is appropriate to be used as complementary to optical sensor data of land sat ,SPOT and MOS, etc NRCT also plans to acquire the Indian IRS data and to own and operate .Thai Remote Sensing Satellite System (Smallest Program ),an optical sensor satellite to be launched in the next five year

2 Present and Future Availability of Satellite data
Thailand ground receive station currently acquire data from both optical sensor of Landsat ,SPOT,MOS,NOAA and SAR sensor of the Japanese JERS-1 and ERS -1 of European Space Agency .with the extensive archive of multilevel data , NRCT through the User Services Center presently offers to the users various scales , formats and correction levels of the photographic and digital products comprising :
  1. Photographic product , both in film and paper prints in black & white or color at various scale and correction level; bulk, georeferenced and geocoded.
  2. Digital product in the media of both computer compatible tape(CCT) and 8 mm. Cartridge tape with the option of BIL/BSQ format for TM & SPOT and CEOS for ERS-1 and density of 1600\6250 bpi for CCT and 2.3/5.0 GB for cartridge tape.
Users who are interested un the data over particular area under Thai station's coverage ,could access the catalog locally or remotely. In recognition of the users' need for easy query of the station's data archive, NRCT also plans to develop a capability to allow querying of station's archive through Internet with World-Wide-web by mid 1996.

A part from the existing facilities, NRCT will upgrade the equipment to receive the Indian IRS-1C and, Thai station for receiving the Canadian Radarsat satellite data, in 1996.

3. Thai Remote Sensing Satellite Program
In October 1994 , the ministry of science , Technology and Environment (MOSTE) concluded MOU with the Canadian Space Agency for cooperation in space technology and applications. Consequently ,Thai Government recently gave the provisional approval to NRCT to proceed with the Thai Remote Sensing Satellite program.

MOSTE through the National Research Council of Thailand will own and operate the satellite system. It will be the first satellite to operate in an orbit dedicated to the equatorial regions. The unique feature of this system design will give Thailand a leadership position in Southeast Asia and the global equatorial belt in general. Thailand will be able to assume a role in the international effort to use space to monitor the earth's resources and environment and to assist sustainable development. It also a great opportunity to provide significant human resources development and could be the first step in developing a space related industry in Thailand .

(I) Overall Description
The performance parameters of the Thai Remote Sensing Satellite System are summarized in the following tables:

Table 1 mission performance
Parameter Value
Mission life 5 years
Orbit type 73 orbits / 5 days multi-sun-synchronous
Orbit period 97 minutes
Orbit inclination 28 degrees
Orbit altitude 600 km
Coverage repeat Every 5 days
Illumination repeat 49 days
Command uplink S -Band; 2 kbps
Telemetry downlink S-Band: Direct 2/ 4 kbps Playback 32/ 128 kbps
Data downlink X -Band: <85Mbps

Table 2 Temporal performance
Parameter Value
Revisit time Twice every 5 days
Accessibility Region 29.6 °N to 29.6 °S
Maximum Imaging Capability 10 minutes/orbit
Usable opportunities per year 63

Table 3 Spatial Performance
Parameter Value
Swath width 185 km imaged swath which is selectable within a 275 km
Across Track Resolution 30/m (nadir)
Along Track Resolution 30/m (nadir)
Geometric Distortion <1/2 pixel
Band to Band registration <1 pixel
Image location <5km

Table 4 Spectral Performance
Parameter Value
Spectral bandwidths:  
Blue 0.45 to 0.52 µm ( + - )0.1
Green 0.52 to 0.60 µm ( + - )0.1
Red 0.63 to 0.69 µm ( + - )0.1
NIR 0.76 to 0.90 µm ( + - )0.1

4. Conclusion
As NRCT has over fifteen years equipped with remote sensing capabilities both for date reception and extensive applications , now Thailand is embarking on a new direction through Thai remote sensing satellite System . This will not only benefit Thailand but would also provide new opportunity for international collaboration.