Since launched in May 2004, FORMOSAT-2 is currently the unique high-resolution satellite having capabilities to daily image anywhere worldwide. The image processing system (IPS) was developed indigenously, so that it was helpful for the quick response to emergency events. FORMOSAT-2 has taken the first images and continuously monitoring after large disasters over the world to support the aftermath relief and precaution of secondary disasters, especially for the southern Asia tsunami, the Wilkins Ice Shelf disintegration, the Sichuan earthquake, the typhoon Morakot, and the Japan earthquake. In this paper we introduce the background, the goal, the system, and the operations of the Image Processing System (IPS), and the imaging activities and applications for the large events for nine years. IPS includes five subsystems: Planning and Scheduling Subsystem ( PSS), Data Ingestion Subsystem (DIS), Data Processing Subsystem (DPS), Data Management Subsystem (DMS), and Image Quality Subsystem (IQS). FORMOSAT-5 project is to build the indigenous capabilities of the spacecraft bus and the remote sensing instrument, and to continue the FORMOSAT-2 mission. It will provide the higher resolution images with the capabilities of imaging along the meridian or along the coastline. To meet the requirements and take the challenge, IPS will further utilize the network technology to provide the next-generation image products integrated with GIS.

Launched on May 20, 2004, the primary mission objective of FORMOSAT-2 is to acquire remotely sensed data to support domestic and international remote sensing researches for various applications. Providing a major disaster occurred, series of satellite data obtained at the first available time would be helpful for analyzing initial impacts and monitoring the following situations. To provide emergency service for disaster reduction operations, National Space Organization (NSPO) utilized multi-processing techniques to improve the efficiency of its image processing system. Also, a web-based sensor planning service compliant to OGC standard is developed. With which, the data from multiple satellites could be integrated properly to support disaster reduction activities. Aimed at visualization of the integrated data from sensor-web and analysis results from different scientific and application models, National Applied Research Laboratories (NARL) has conducted the development of a 3-D environmental application and disaster reduction platform. With this near real-time high resolution platform, one can visualize information integrated from FORMOSAT-2 and other sources and make a better decision for disaster reduction operations.

Scheduled to be launched in 2015, FORMOSAT-5 (FS5), equipped with 2-m panchromatic and 4-mmulti-spectral imaging sensor, is the Taiwan first self-reliant remote sensing satellite. Instead of using the traditional CCD sensor, FS5 RSI is equipped with a CMOS image sensor, the world's first commercial remote sensing CMOS image sensor. There are significant challenges in both performance and manufacturing. This article records the important RSI systems engineering processes and technical studies according to the basic systems engineering process (such as the requirement allocation, system analysis, and verification), and the development experience in FS5. Remote sensing instrument development experience from many domestic and foreign experts and scholars is being integrated into FS5 program. The systems engineering process example could become a guideline and basis for developing the future remote sensing payload. The technical part of this paper mainly focuses on the exploration of the key performance parameters such as system contrast transfer function (CTF), signal to noise ratio (SNR) etc.

FORMOSAT-5 is the first space program that National Space Organization (NSPO) takes full responsibility for the complete satellite system engineering design including payloads. FORMOSAT-5 will operate in a sun synchronous orbit at 720-km altitude with 98.28-degree inclination angle. The optical Remote Sensing Instrument (RSI) is a multispectral imager which contains one panchromatic band with 2-m ground sampling distance (GSD) and four multispectral bands with 4-m GSD. A Cassegrain type of RSI with two reflective aspheric mirrors and spherical corrector lens is designed. The space thermal environment is one of the important factors that affect the image quality of a space optical RSI. TRASYS and SINDA model of RSI have been established for thermal analysis. Both hot and cold cases have been studied. Thermal induced instabilities are incorporated in optical models (e.g., OSLO) by use of Zernike polynomial coefficients to calculate the system MTF and WFE. It is investigated that thermal deformation of RSI structure and mirrors will impact the optical performance. The relationship among temperature distributions, thermal deformations and image degradation of on-orbit behaviors are discussed.

Remote Sensing satellite shall be provided with complex redundant functions owing to its high reliability requirement. However, for generating its corresponding reliability block diagrams come from understanding operational scenarios, dependencies between the electrical circuits in the system and following the circuit’s characteristics. For a reliability block diagram contained redundant designs, normally the corresponding mathematical formulas of that reliability can be mapped accordingly. If no proper formula for that design can be used, the derivation of the fitting equations is necessary. In the reliability block diagram, most of the internal electrical parts have serial relationships. Hence, a grand total of the failure rates of the electrical parts can retrieve the failure rate in that block unit. Furthermore, to follow the reliability block diagram can evaluate the prediction of system reliability. This paper will describe the processes of reliability prediction in the Remote Sensing satellite system for referring in the future missions or predicting other complex systems.

Scheduled to be launched in 2015, FORMOSAT-5, equipped with 2 m panchromatic and 4 m multi-spectral imaging sensor, is the Taiwan first self-reliant remote sensing satellite. To increase the efficiency for FORMOSAT-5 to acquire images on the ground, a function, so called “smart agility” or asynchronous imaging, is designed in FORMOSAT-5. With the function of asynchronous imaging, FORMOSAT-5 can rotate its body when it acquires images along a given specific direction on the ground. To verify the feasibility of smart agility mode for FORMOSAT-5, NSPO conducts a series of verification processes based on the sequence of satellite imaging. Firstly, the satellite attitude algorithm for asynchronous imaging mode was derived. Secondly, satellite on-board AOCS algorithm was developed. Lastly, simulated image was demonstrated. The aim of this article is to introduce some research results for asynchronous imaging in NSPO, including algorithms to calculate satellite attitude in asynchronous imaging mode, and asynchronous images simulation.