Satoshi Ichikawa

Onboard Image Processing System for Hyperspectral Sensor.

Onboard image processing systems for a hyperspectral sensor have been developed in order to maximize image data transmission efficiency for large volume and high speed data downlink capacity. Since more than 100 channels are required for hyperspectral sensors on Earth observation satellites, fast and small-footprint lossless image compression capability is essential for reducing the size and weight of a sensor system. A fast lossless image compression algorithm has been developed, and is implemented in the onboard correction circuitry of sensitivity and linearity of Complementary Metal Oxide Semiconductor (CMOS) sensors in order to maximize the compression ratio. The employed image compression method is based on Fast, Efficient, Lossless Image compression System (FELICS), which is a hierarchical predictive coding method with resolution scaling. To improve FELICS’s performance of image decorrelation and entropy coding, we apply a two-dimensional interpolation prediction and adaptive Golomb-Rice coding. It supports progressive decompression using resolution scaling while still maintaining superior performance measured as speed and complexity. Coding efficiency and compression speed enlarge the effective capacity of signal transmission channels, which lead to reducing onboard hardware by multiplexing sensor signals into a reduced number of compression circuits. The circuitry is embedded into the data formatter of the sensor system without adding size, weight, power consumption, and fabrication cost.

Fast Compression Implementation for Hyperspectral Sensor

Fast and small foot print lossless image compressors aiming at hyper-spectral sensor for the earth observation satellite have been developed. Since more than one hundred channels are required for hyper-spectral sensors on optical observation satellites, fast compression algorithm with small foot print implementation is essential for reducing encoder size and weight resulting in realizing light-weight and small-size sensor system. The image compression method should have low complexity in order to reduce size and weight of the sensor signal processing unit, power consumption and fabrication cost. Coding efficiency and compression speed enables enlargement of the capacity of signal compression channels, which resulted in reducing signal compression channels onboard by multiplexing sensor signal channels into reduced number of compression channels. The employed method is based on FELICS1, which is hierarchical predictive coding method with resolution scaling. To improve FELICSs performance of image decorrelation and entropy coding, we applied two-dimensional interpolation prediction and adaptive Golomb-Rice coding, which enables small footprint. It supports progressive decompression using resolution scaling, whilst still delivering superior performance as measured by speed and complexity. The small footprint circuitry is embedded into the hyper-spectral sensor data formatter. In consequence, lossless compression function has been added without additional size and weight.

High-Speed 200Gbytes Data Recorder Utilizing the 512Mbits SDRAM and CompactPCI Bus

In 1999, the Japan Aerospace Exploration Agency (JAXA) began developing a high-speed, large-volume and low-power-consumption Solid State Recorder (SSR) for space-use. This aim was to develop a SSR for installation of Earth observation satellites that could store and process large amounts of data. A prototype of the SSR was completed in spring 2004, and an engineering model is currently being constructed. The main features of the SSR are 200GBytes capacity, 2.5Gbps data transmission speed, low weight (25kg) and low power consumption (120W). A 512Mbits Synchronous Dynamic Random Access Memory (SDRAM) with on-board multi-bit Error Detection and Correction (EDAC) mechanism, as well as a CompactPCI bus for fast data exchange, are used to improve the efficiency of data collection and storage capabilities. In this paper, we describe the main feature of the SSR system, and the technologies used in its development and manufacture. Preliminary results of several system tests are also reported. In addition, results of experiments with an older generation SSR on the Mission Demonstration test Satellite-1 (MDS-1), which sought to demonstrate a practical solid-state type recorder in the space environment, are briefly introduced.

24.4 A 6.5Gb/s Shared bus using electromagnetic connectors for downsizing and lightening satellite processor system by 60%

Processor systems that are mounted in satellites must be small and light, having high data transfer rates, and high storage capacity [1]. A small reduction in size and weight could reduce the cost of launching a satellite by a significant amount. The next generation of earth observation satellites will require data transmission rates to a maximum of 20Gb/s and at least one terabyte of storage capacity. The volume, weight, and communication speed of the processor system is determined by the backplane connectors (Fig. 20.4.1). It is difficult to achieve a connector that can pass signals of 2.5Gb/s or more. The signal reflection that occurs when signals are branched at connectors and at the wire stubs of branches decreases the transmission speed, so only point-to-point connections are possible. Once the satellite is launched, repair or replacement is not possible, and system redundancy is introduced. Accordingly, 512 backplane wires would be required. The signal connector would require 1,024pins, including the ground pins used to prevent crosstalk, and would be 512mm wide, which is even wider than the circuit board of each module.

Development of onboard fast lossless compressors for multi and hyperspectral sensors

Fast and small-footprint lossless compressors for multi and hyper-spectral sensors have been developed. The compressors are employed for HISUI (Hyper-spectral Imager SUIte: the next Japanese earth observation project that will be on board ALOS-3). By using spectral correlations, the compressor achieved the throughput of 30Mpel/sec for hyper-spectral images and 34Mpel/sec for multi-spectral images, which covers the data acquisition throughput of HISUI, on a radiation tolerant FPGA (field-programmable-gated-array). We also implemented the compressor on the evaluation model device of HISUI, and confirmed its feasibility and compression performance of actual hyper-spectral sensor data.

Total dose environment in SSR component on board Tsubasa (MDS-1) Satellite

Total dose data in solid-state recorder (SSR) component on board Tsubasa (MDS-1) satellite, flying in a highly eccentric orbit, is analyzed. 14 small dosimeters using RADFET were arranged in different shielding positions of the SSR component The initial total dose data in these positions are presented.