Geo-Informatics and Space Technology Development Agency (GISTDA)
CEOS WGISS – 25February 25-29, 2008
Sanya, Hainan Island, China
THEOS / Land Surface Imaging
Suwan VongvivatanakijTHEOS Engineer
Geo-Informatics and Space Technology Development Agency (GISTDA)
Content
THEOS Introduction Satellite Performance
THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression
THEOS Current Status THEOS Future Service
Geo-Informatics and Space Technology Development Agency (GISTDA)
Content
THEOS Introduction Satellite Performance
THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression
THEOS Current Status THEOS Future Service
Geo-Informatics and Space Technology Development Agency (GISTDA)
THEOS Satellite: Bus
Total mass 750 kg
Dimensions 2.1 x 2.1 x 2.4 m
Solar array 800 W
Nominal Lifetime > 5 years
Hydrazine 80 kg
Recording capacity 40 Gbit solid-state memory
Image Telemetry 120 Mbit/sec (X band)
Off-nadir viewing +/- 50º (roll and pitch)
Attitude control Earth pointing and high agility
Orbit determination GPS
Geo-Informatics and Space Technology Development Agency (GISTDA)
THEOS Satellite : Payload
PAN MSResolution (m) / Imaging swath (km) 2 / 22 15 / 90
Spectral ranges (um) 0.45 – 0.90 B1 (Blue): 0.45-0.52
B2 (Green): 0.53-0.60
B3 (Red): 0.62-0.69
B4 (NIR): 0.77-0.90
Signal to Noise Ratio > 90 >100
Imaging dynamics 8 bits among 12 bits
Absolute localizations accuracy (level 1B) < 300 m
Onboard image processing 2.8 or 3.7 compression ratio (DCT)
Optical Payload Panchromatic Camera Multispectral Camera
Geo-Informatics and Space Technology Development Agency (GISTDA)
THEOS Performance
Orbit Type Circular SSO low earth orbit
Altitude 822 km
No of Orbits per Day 14+5/26 orbits per day
Local Equator Crossing Time
10:00 am (descending)
Orbit Period 101 minutes
Orbit Inclination 98.7°
Orbit Cycle 26 days (369 orbits)
Distance Between Passes (at Equator)
108 km (Between 2 closest passes)
2800 km (Between 2 consecutive passes)
Coverage Area Radius more than 2000 km from Ground Station
Geo-Informatics and Space Technology Development Agency (GISTDA)
Coverage Area
Geo-Informatics and Space Technology Development Agency (GISTDA)
Content
THEOS Introduction Satellite Performance
THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression
THEOS Current Status THEOS Future Service
Geo-Informatics and Space Technology Development Agency (GISTDA)
Acquisition Type
THEOS System allows 2 different missions. Panchromatic, high resolution rather small FOV Multispectral, medium resolution with large FOV
Panchromatic Class of Quickbird to Formosat 2 (10 to 20 km swath) More dedicated to cartography, local land use, monitoring
and security
Multispectral Class of Spot, Landsat, IRS (>60 km swath) More dedicated to agriculture, forestry, natural resources
and management
Geo-Informatics and Space Technology Development Agency (GISTDA)
PAN Sharpening Image
PAN
MS
PAN Sharpening
=
Geo-Informatics and Space Technology Development Agency (GISTDA)
Geometrical Conditions 3 different domains of pointing
Nadir (pointing angle <12° from nadir) Nominal (up to 30° from nadir) Full (up to 50° in roll and 45° in pitch)
Nadir condition At 30° roll, the effective resolution is about 2.4 x 2.6
meters. Recommended for the acquisitions on cities or when the
highest resolution is required. Outside nominal condition
Pixel size is increased by a factor 3 across track and 1.7 along track.
Geometrical degradation: with roll angle of 50° Especially useful for emergency cases
Geo-Informatics and Space Technology Development Agency (GISTDA)
Accessibility Performance
5 days full accessibility performance with 30° roll angle
1st day
2 consecutive days
3 consecutive days
4 consecutive days
5 consecutive days
Geo-Informatics and Space Technology Development Agency (GISTDA)
Accessibility Performance
2 days full accessibility performance with 50° roll angle
no access of on 1st day access on 1st day access on 2nd day Double access over 2 day
1st day 2 consecutive days
Geo-Informatics and Space Technology Development Agency (GISTDA)
Geometrical Conditions
With up to 50° roll, the accessibility is better than 1 day for 90% of the earth.
High pitch is to be able to take several images of the same area in one pass.
Stereo Image
Geo-Informatics and Space Technology Development Agency (GISTDA)
Gains
THEOS images are coded on 8 bits. Capability to choose these 8 bits among the 12 bits
available after the Analog to Digital Converter.
2 analogue gains with a factor √ 2 between each
5 digital gains with a factor 2 between each
This gives 10 different gains.
The transmitted bits are in white.
Geo-Informatics and Space Technology Development Agency (GISTDA)
Compression
On-board compression allows for 2 different compression ratio: High ≈ 3.8 Low ≈ 2.8
High compression ratio give good image quality for all the THEOS images.
Low compression ratio is suitable for complex contents such as urban areas MS images for agricultural application usually need good
signal to noise ratio with low compression ratio
Geo-Informatics and Space Technology Development Agency (GISTDA)
Content
THEOS Introduction Satellite Performance
THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression
THEOS Current Status THEOS Future Service
Geo-Informatics and Space Technology Development Agency (GISTDA)
Satellite
The satellite is fully integrated and all the tests results confirmed that the satellite is compliance with the specifications.
Flight Aptitude Review was considered as closed.
Satellite was ship to launch site (Yasny, Russia)
Now, Satellite is in storage and ready for launch.
Geo-Informatics and Space Technology Development Agency (GISTDA)
Ground Segment
The infrastructure which consisted of Control Ground Segment and Image Ground Segment have been well prepared.
Both hardware and software are installed and tested successfully.
On-Site Training: Flight Operation Team have been qualified with their back up.
Siracha, Chonburi Province Thailand
Geo-Informatics and Space Technology Development Agency (GISTDA)
Launcher
The Dnepr launcher is being integrated. Final Acceptance of launch base
infrastructure was ready to start launch campaign activities.
Geo-Informatics and Space Technology Development Agency (GISTDA)
Launch Campaign
The schedule depends on the drop zone authorization which is subject to the political and intergovernmental agreement between Russia and Uzbekistan.
Geo-Informatics and Space Technology Development Agency (GISTDA)
Content
THEOS Introduction Satellite Performance
THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression
THEOS Current Status THEOS Future Service
Geo-Informatics and Space Technology Development Agency (GISTDA)
THEOS GeoPortal
Browse and request satellite images from the catalogue through web interface
Keep track of ordering and production status by user account
Delivery products to customer through FTP
Geo-Informatics and Space Technology Development Agency (GISTDA)
Conclusion
Monitor and Support the exploitation of resources & other disciplines with the advantage of High Resolution and Large Swath Width, Frequent Time visit
High Agility with 2 pushbroom scanning optical instruments
Large visibility circle covering Main Part of Asia Satellite, Ground, Launcher are ready and expected
to be launched soon. Quick and easy service with browsing, ordering,
tracking and delivery by THEOS GeoPortal
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