SI-100 platform is a flexible system for relatively small sized payloads. It is designed to satisfy the mission requirements by incorporating three-axis stabilized, accurate and agile attitude control. Dual redundancies are adapted where necessary in the system architecture design to increase the reliability of the satellite system.

SI-100 platform, whose size is 0.65 m in width, 0.6 m in length and 0.85 m in height, has volume and mass suitable for piggy-back satellite launchers. For fixed solar panels, 1 or 2 deployable panel configuration is feasible for maximum 200 W generation upon requirements.

 The performance specifications are subject to change in accordance with customers’ missions and requirements.

SI-200 architecture is suitable for small satellites where the accommodation of earth observation and/or science payload is required. SI-200 platform is designed to satisfy the mission requirements by incorporating three-axis stabilized, accurate and agile attitude control for precise imaging operations. Dual redundancies are adapted where necessary in the system architecture design to increase the reliability of the satellite system.

SI-200 platform, whose size is 1.2 m in diameter and 1.35 m in height, features deck-and-longeron type structure permitting easy assembly and disassembly. The interface with the launch vehicle is made through an adapter bolted to the bottom of the structure. The mechanical interface with the electro-optical payload is provided through three points at the satellite middle deck.

The performance specifications are subject to change in accordance with customers’ missions and requirements.

SI-200E is the extended version of SI-200 platform which has flight heritage with RazakSAT of Malaysia and DubaiSAT-1 of UAE. Its architecture is designed to accommodate an Earth observation and/or science payload. Hall Effect Propulsion System (HEPS) is installed for orbit control and maintenance. Accurate and agile three-axis attitude control supports precise imaging operations. Dual redundancies are adapted where necessary in the system architecture design to increase the reliability of the satellite system.

EOS-A payload is an ideal imaging system suitable for 100 kg class satellites and has been applied for Singaporean X-SAT and Turkish RASAT, both of which are expected to reach the Low Earth Orbit (LEO) in 2010.

EOS-A has two baseline options:
-   10 m resolution in multispectral bands (RG + NIR) with 50 km swath-width
-   7.5 m in panchromatic band and 15 m in multi-spectral bands (RGB) with
    30 km swath-width.
Based on the baseline options, the system parameters of the EOS-A are customized for customer’s specific missions.

EOS-C optical payload is a push-broom type camera with 2.5 m Ground Sampling Distance (GSD) for a panchromatic band and 5 m GSD for four multi-spectral bands. The swath width of the generated image is wider than 20 km. A solid-state recorder is implemented to receive, process and store the image data. The image data is downloaded in X-band.

EOS-D optical payload is a push-broom type camera with 1 m Ground Sampling Distance (GSD) for a panchromatic band and 4 m GSD for four multi-spectral bands. The swath width of the generated image is wider than 12 km. A high performance solid-state recorder is installed to receive, process, store, and transmit the image data in high speed. During the transmission of the stored image data using X-band transmitter, the solid-state recorder compresses, encrypts, and encodes the data in real time.

IRPS receives image data from the satellite, processes the data to the predetermined level and distributes image product to users. It generates highly accurate image products in a systematic and automatic manner. SI developed IRPS has supported numerous satellite operations such as KOMPSAT-1, KOMPSAT-2, RazakSAT and DubaiSat-1. This IRPS is based on a multi-satellite data handling capability and an easily expendable architecture in order to receive and process image data from additional satellites by using a simple data format interpretation module.

IRPS Configuration

 

 

IMAGE COLLECTION PLAN SUBSYSTEM (ICPS)
ICPS is used to make a plan for imaging and downlink schedule. It displays orbit and NTO on the map for operator to make imaging plans. It also manages satellite resources and check conflict between orders. ICPS also guides operator with weather forecast data to make imaging plans to get cloud free images and with radiance map to define the TDI value. ICPS finally generates daily imaging collection plan (ICP), which is transferred to MCS for satellite programming.

DIRECT INGESTION SUBSYSTEM (DIS)
DIS receives and archives the data from the satellite and provides the moving window display. The COTS receiver receives IF signal, demodulate, and then provide bit stream data to DIS receivers via Direct Receiving Card (DRC). DIS receiver provides high speed real-time CCSDS decoding (ASM synchronization, de-randomizing, and RS decoding) using Direct Receiving Card (DRC), real-time decryption of AES and formatting to Level 0F. Level 0F is image and ancillary data internally defined, which is used as an input to PMS for products generation. The processed Level 0F data is archived into internal RAID disks. During reception DIS provides real-time Moving Window Display and displays link quality using the result of RS decoding. DIS operates autonomously based on the mission timeline with hot-redundancy configuration. The archived data are transferred to PMS for catalog and product generation.

 

PRODUCT MANAGEMENT SUBSYSTEM (PMS)
PMS extracts scenes and produces image product at a pre-defined processing level. The image data from DIS are converted into image products. PMS is also responsible for the data backup management. PMS can be configured with several product generator workstations to have better performance.

Upon operator’s and/or user’s requests, PMS can generate scene products of different levels as follows:

·     Level 0: Radiometrically corrected

·     Level 1: Systematically geocoded

·     Level 2: Precision geocoded

·     Level 3: Ortho-rectified (DEM should be provided)

A Sun Sensor is a widely used simple attitude determination sensor. FSS-05 generates 2-axis solar angle information using four solar cells. It has two orthogonal slits for 2-axis measurement. The accuracy of FSS-05 is better than 0.5 degrees after calibration. FSS-05 is reliable and affordable for every space mission.

Magnetometer is one of the widely used attitude determination sensor. MAG-30 is a flux-gate type sensor and generates three-axis magnetic field information. The accuracy of MAG-30 is better than ± 30 nT after calibration. MAG-30 is reliable and affordable for every space mission.

Magnetic Torquer is widely used momentum dumping attitude control hardware. MTD-3 can drive magnetic coils in 3-axis with 128 steps (0~127). MTD-3 is a reliable component with many flight heritages in many space missions.

Magnetic Torquer is widely used magnetic control momentum dumping attitude control hardware. MTR-50 can generate ± 20 Am2 magnetic dipole moments with small hysteresis characteristics.

SI has dedicated to development of star trackers since 1994 and has experienced in-flight operation of precise attitude determination with the star trackers. SST-20A is an outgrowth of the SST10 that is the second generation star tracker of SI. The reliability and performance are improved by using RH or RT parts, and extensive environmental test. A fast and robust star identification algorithm is implemented on the SST-20A and guarantees the success rate up to 99% in full sky search. The accuracy of SST-20 is better than 10 arcsec along with the bore-sight direction. And it can also provide the dual-head configuration to improve the roll accuracy and reliability. SST-20A is has a reliable and affordable design based on flight heritages in many space missions.

SI has dedicated to development of star trackers since 1994 and has experienced in-flight operation of precise attitude determination with the star trackers. SST-20S is an outgrowth of the SST10 that is the second generation star tracker of SI. The reliability and performance are improved by using RH or RT parts, and extensive environmental test. A fast and robust star identification algorithm is implemented on the SST-20S and guarantees the success rate up to 99% in full sky search. The accuracy of SST-20S is better than 10 arcsec across the bore-sight direction. SST-20S has a reliable and affordable design based on flight heritages in many space missions.

GPS-12 can receive L1 C/A code from 12 GPS satellites at a time. It provides time, position and velocity information. Its time and position accuracies are 1 μs and ± 100 m for LEO operation. It is applicable for satellite orbit operation environments.

X-band carrier frequency is generated using PLDRO and is connected to the QPSK modulator with I-Q signal. This modulated signal is amplified using High Power Amplifier (HPA) and radiated by the X-band antenna. XTX-30 transmits image data to the ground stations using QPSK modulation at 30 Mbps.
Baseband circuits receive I-Q digital signals (LVDS) from payload. PLDRO, PLL synthesizer, drive amplifier and QPSK modulator compose the modulation unit. Oven Controlled Crystal Oscillator (OCXO) is used in the PLL synthesizer for high stability.