CEOS WGISS – 25 February 25-29, 2008 Sanya, Hainan Island, China Geo-Informatics and Space Technology Development Agency (GISTDA) THEOS / Land Surface.

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

[email protected]


Content

THEOS Introduction Satellite Performance

THEOS Imaging Acquisition Type Geometrical Conditions Gains & Compression

THEOS Current Status THEOS Future Service


Content





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


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


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


Coverage Area


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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


PAN Sharpening Image

PAN

MS

PAN Sharpening

=


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


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


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


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


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.


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


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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.


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


Launcher

The Dnepr launcher is being integrated. Final Acceptance of launch base

infrastructure was ready to start launch campaign activities.


Launch Campaign

The schedule depends on the drop zone authorization which is subject to the political and intergovernmental agreement between Russia and Uzbekistan.


Content





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


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

CEOS WGISS – 25 February 25-29, 2008 Sanya, Hainan Island, China Geo-Informatics and Space Technology Development Agency (GISTDA) THEOS / Land Surface.

Documents

china geoinformatics

management slide

imaging swath

imaging dynamics

orbit cycle26 days

high resolution

small fov multispectral

payload panms resolution