The Instrument Processing Unit (IPU) has been developed in the frame of Airbus Defence and Space’s new generation of Low Earth Orbit observation satellite. Derived from the already flight proven High Resolution Sensor (HRS), it features high performances and cost effectiveness. The main functions of this unit are the video processing and image compression of CCD signals. The design is based on state of the art analog to digital converters (12bits/40Msps) and on an improved JPEG compression algorithm delivering a constant output data rate.
The IPU receives input signals from two Focal Plane front-end electronics, which can use either a Panchromatic single line CCD or/and a multi-spectral four lines CCD. It delivers the compressed image data to a solid state mass memory Unit.
IPU is based on 5 types of boards :
• Video board, handling 4 simultaneous analog digitalization channels, with numerical processing to manage the Black reference pixels, the Correlated Double Sampling (CDS), several gains, a pixel ’s non-uniformity correction and a pixel Binning.
• Reordering Compression Regulation board, delivering simultaneously two JPEG compressed data streams from any video input segment arrangement (minimum is one segment up to 12Mpix/s and maximum is four segments up to 12Mpix/s).
• House keeping board, supplying all the clocks to external front-end CCD electronics
• Heater control board to manage the thermal stability of the instrument
• Distributed Power supply for all the IPU boards plus the external Focal planes
The Instrument Processing Unit (IPU) is gathering the instrument electronics functions in a modular and highly integrated assembly of 8 slots. It is possible to add one more board in order to implement some new functions (like multiplexing). A full redundancy can be achieved by using two identical units implemented in a cold redundant configuration. All the necessary cross-strapping is included inside it.
• Input data : 2x 4x12Bits up to 12Mpixel/s, Analog Bandwidth better than 30MHz
• 2 to 10 compression ratio, with up to 24 Kpixels/line, JPEG Picture Quality (Flat Matrix /4 Huffman tables)
• Output Data throughput : 2x 8bits/36Mpix/s (Max 48Mpix/s for one)
• Power supply voltage : 22 V to 39V unregulated power rail
• Typical power consumption :100 W
• Mass :14 kg
• Dimensions :345 x 280 x 265 mm
High resolution imaging systems
SPOT 5 High Resolution Stereoscopic Instrument.