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Geo-Informatics and Space Technology Development Agency (Public Organization):GISTDA

GISTDA To be Value based Organization in Geo-space Intelligence Deliveries by 2020

Thaichote

Thaichote

Thaichote

itheos1.jpg

Thaichote the first Earth observation satellite of Thailand, was successfully launched by Dnepr launcher from Yasny, Russian Federation, on Wednesday, October 1, 2008 at 06:37:16 UTC (Universal Time Coordinated) or 13:37:16 hours, Bangkok Time.

Satellite Characteristic

Launch mass 715 kg.
Dimensions 2.1 m. x 2.1 m. x 2.4 m.
Solar array 840 Watt
Hydrazine 82 kg.
Recording capacity 51 Gbit (BOL) solid-state memory
Onboard image processing 2.8 or 3.75 compression ratio (DCT)
Image telemetry 120 Mbit/s (X band)
Attitude control Earth pointing and high agility
Orbit determination GPS
Payload 1 PAN and 1 MS cameras
Orbit Sun-synchronous (14+5/26 orbits per day)
Inclination 98.7°
Altitude at equator 822 km
Period 101.4 min
Local equator crossing time 10:00 am (Descending)
Sub-satellite point velocity 6.6 km/s
Nominal life time 5 years
Thaichote Sensors itheos_pan.jpg itheos_multi.jpg
  Panchromatic Multispectral
Wavelength P : 0.45 - 0.90 µm B0 (blue) : 0.45 - 0.52 µm
B1 (green) : 0.53 - 0.60 µm
B2 (red) : 0.62 - 0.69 µm
B3 (near infrared) : 0.77 - 0.90 µm
Resolution 2 m. 15 m.
Swath width 22 km. (nadir) 90 km. (nadir)
Number of pixels 12,000 pixels 6,000 pixels
Access corridor width 1,000 km. 1,100 km.

t00005.jpg

 

Thaichote Image Capturing

itheos_nadir.jpg Nadir imaging

The PAN strip is 22 km width and theMS strip is about 90 km width at nadir.

itheos_strip.jpg Scene and strip imaging

Scenes are defined as a square portion of the imagedstrip. An image strip can be acquired continuously with a length of up to 10 minutes, which is an equivalent of approximately 4,000 km

itheos_3axis.jpg Repeat viewing capability

Thaichote oblique viewing capability allows for the imaging of any area within a 1000 kilometer swath (for 30° roll). Oblique viewing can be used to increasethe viewing frequency for a given point during a givencycle. The frequency varies with latitude: over Thailand, a given area can be imaged 9 times duringthe same 26-days orbital cycle. This means a yearly revisit of 126 times and an average of 3 days, with an interval ranging from a minimum of 1 day to a maximum of 5 days.

itheos_stereo.jpg Stereo Imaging

Stereo pair can be used for relief perception and elevation plotting (Digital Elevation Modelling). Thesestereo images can be acquired by Thaichote with 2 different methods:
1. The programming of two images of the same areaon the ground acquired at different roll viewing angles on successive satellite passes
2. The pitch agility allows acquiring a stereo pair in thesame pass at less than 5 mn delay.

 

Thaichote Products

The Thaichote imagery product is available in a variety of product options. These product options use different spectral band combinations and imply differences in the pixel resolution of the final product.

Product Option
Black & White
Blue
Green
Red
Near Infrared
Resolution
Panchromatic
x
-
-
-
-
2 meter
Multispectral
-
x
x
x
x
15 meter
Pan-Sharpened
x
x
x
x
x
2 meter

Sampled THEOS data products

 

Multispectral Products
Panchromatic Products
Pan-Sharpened Products

Thaichote multispectral products provide 15 meter resolution (at nadir) and 8 bits information depth. All four bands are delivered as one file. The output scene is a square scene of 90 km. x 90 km.

Thaichote panchromatic products provide 2 meter resolution (at nadir) and 8 bits information depth. The output scene is a square scene of 22 km. x 22 km. . Thaichote imagery products are also available in a 4-band pan-sharpened product option. These products combine the visual information of 4 multispectral bands (blue, green, red, Near IR), with the spatial information of the panchromatic band. Pan-Sharpened products are available as product option for level 2A only. The output scene is a square scene of 22 km. x 22 km.

 

Corrective Levels

Thaichote products are provided into two correction levels:

  • System Corrected Level (1A)
    Level 1A images are radiometrically corrected: in addition to level 0 pre-processing operation, the detector equalization and radiometric abnormality removal (missing lines, invalid detectors, and compression errors) are performed.
    The PAN band and the MS reference band B1 are always geometrically raw.
    Level 1A products are geo-referenced: it means that product annotations provide information about the image localization. (detail)
  • Geo-Corrected Level (2A)
    Level 2A images are radiometrically corrected and geocoded, i.e. resampled on a cartographic grid.
    Level 2A Imagery products are suitable for users requiring modest absolute accuracy and/or large area coverage. Users of Standard Imagery products usually possess sufficient image processing tools and knowledge to manipulate and exploit the imagery for a wide variety of applications. ) (detail)

Area Type

  1. Single Strip
    • Product Options: PAN (22 km wide) or MS (90 km wide) or PAN Sharpened (22 km wide)
    • Customer specifies center(lat/long in degree) and length (km)
    • One scene minimum is required (PAN or PAN Sharpened: 22X22 km,
      MS: 90X90 km)
  2. Single Strip: Stereo Forward/After
    • Product Options: PAN (22 km wide) or MS (90 km wide)
    • Customer specifies center(degree) and length (km)
    • One scene minimum is required (PAN or PAN Sharpened: 22X22 km,
      MS: 90X90 km)
  3. Single Strip: Stereo Right/Left
    • Product Options: PAN (22 km wide) or MS (90 km wide)
    • Customer specifies center(degree) and length (km)
    • One scene minimum is required (PAN or PAN Sharpened: 22X22 km,
      MS: 90X90 km)
  4. Rectangle
    • Product Options: PAN or MS or PAN Sharpened
    • Customer specifies at least upper left and lower right corner coordinates (degree)
    • One scene minimum is required (PAN or PAN Sharpened: 22X22 km,
      MS: 90X90 km)
  5. Polygon
    • Product Options: PAN or MS or PAN Sharpened
    • Customer specifies all coordinates (maximum of 20) provided in counter clockwise
    • One scene minimum is required (PAN or PAN Sharpened: 22X22 km,
      MS: 90X90 km)