Scientific Payload

Functional requirements summary



The temperature of vegetation fires varies from 500 up to 1200 K, depending on the type of combustion. Their spectral density distribution occurs in the mid-wave infrared (MIR) wavelength region at 3-5 µm. Hence it is the main target for a space-born fire sensor. Reflection effects (e.g. sun glint) as sources of data misinterpretation have to be distinguished by combination of MIR and VIS (visible) channels.Furthermore temperature information have to be derived from thermal infrared (TIR) imaging data by bi-spectral data processing techniques. The so arising multi-channel system is able to detect hot spots of sub-pixel size.

BIRD Payload Requirement
Function Hot-spot detection, hot-spot classification, observation of vulcanoes
Spectral 3.4-4.2 µm, 8.5-9.3 µm, 1 VIS/NIR channel
Radiometric Temp. estimation dynamic range > 2000, saturation limit at T < 1300 K, Rad. Res. IR > 12 bit
Geometric: GSD < 300 m
Geometric: Swath Width As large as possible, min. > 100 km
Other Different visir angles at VIS/NIR
Function Determination of Veg. Index 3 and comparison with the Normalized Diff. Veg. Index
Spectral 840-890 nm, 600-670 nm, 3.4-4.2 µm
Radiometric ≥ 7 bit (VIS/NIR), ≥ 12 bit (MWIR)
Geometric: GSD 100 m - 300 m
Geometric: Swath Width Small
Other Integer pixel size ratio of VIS/NIR + IR pixels
Function Realtime detection of clouds, cloud investigation
Spectral Min. 3 VIS/NIR channels + 1 TIR
Radiometric Dynamic range >1000
Geometric: GSD ≤ 1 km
Geometric: Swath Width Minimum > 100 km
Other Stereo cabability
Function Test of multi-sensor-multi-resolution technique of on-board neural network classification
Spectral 3.4-4.2 µm, 8.5-9.3 µm, 1 or more VIS/NIR channels
Radiometric ≥ 7 bit (VIS/NIR), ≥ 12 bit (IR)
Geometric: GSD 100 m - 300 m
Geometric: Swath Width Small
Other Integer pixel size ratio of VIS/NIR + IR pixels
Function Technological experiments concerning IR-system
Spectral 3.4-4.2 µm, 8.5-9.3 µm
Radiometric Range-level + drift- and detectivity control, pixel alignment

Table 1: Functional mission requirements of BIRD

Payload architecture and parameters

The payload is designed to fulfil the scientific requirements under the conditions of a micro-satellite. It consists of the following main parts:

  • the bi-spectral infrared Hot Spot Recognition System (HSRS incl. MIR and TIR-Sensor)
  • the Wide-Angle Optoelectronic Stereo Sensor (WAOSS-B, VNIR-Sensor) for vegetation analysis and fire classification,
  • the Payload Data Handling system (PDFH) with a mass memory,
  • a neural network classificator for an on-board classification experiment.

The following table summarise the main sensor system parameters of the BIRD instrumentation.

WAOSS-B MIR TIR
Wavelength 600-670 nm
840-900 nm
3.4 - 4.2 µm 8.5 - 9.3 µm
Focal length 21.65 mm 46.39 mm 46.39 mm
Field of View 50° 19° 19°
F-number 2.8 2.0 2.0
Detector 3 CCD-line arrays MCT- line array MCT- line array
Detector cooling passive, 20°C Stirling, 105K Stirling, 80K
Pixel size 7 × 7 µm 30 × 30 µm 30 × 30µm
Number of pixels 2884 2 × 512 staggered 2 × 512 staggered
Quantization 11 bit 14 bit 14 bit
Ground pixel size¹ 185 m 370 m 370 m
Swath width¹ 533 km 190 km 190 km

1 orbit hight = 572 km

WAOSS-B - Wide Angle Optoelectronic Stereo Scanner, modified for BIRD
MIR - Medium Infrared Sensor
TIR - Thermal Infrared Sensor

Table 2: BIRD multi-sensor system parameters (altitude 572km)

 Figure 1: Block scheme of the BIRD payload complex
zum Bild Figure 1: Block scheme of the BIRD payload complex

The Payload Data Handling System (PDH) is the functional integrative part of the BIRD payload. It has data interfaces to all instruments, the spacecraft bus computer and the down-link telemetry channel.

Three main tasks are assigned to the PDH:

  • distribution of high level commands and Housekeeping extraction out of the payload data stream
  • science data storage, telemetry frame generation and down-link
  • on-board thematic data compression

The electronic units of the PDH are arranged within the electronics segment of the spacecraft. The block scheme in Figure 1 shows the functional connections of the instruments and payload units.


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Texte zu diesem Artikel
Infrared Instrumentation (http://www.dlr.de/os/desktopdefault.aspx/tabid-3509/5466_read-7909/usetemplate-print/)
VIS/NIR Sensor System (http://www.dlr.de/os/desktopdefault.aspx/tabid-3509/5466_read-7907/usetemplate-print/)
Platform (http://www.dlr.de/os/desktopdefault.aspx/tabid-3509/5466_read-7905/usetemplate-print/)
Data Handling (http://www.dlr.de/os/desktopdefault.aspx/tabid-3509/5466_read-7903/usetemplate-print/)
Classification (http://www.dlr.de/os/desktopdefault.aspx/tabid-3509/5466_read-7902/usetemplate-print/)