ROCSAT-2 Programming Management and Sheduling
Fengtai Hwang* & Hongyu Chen**
*Assistance Researcher, National Space Program Office (NSPO), Hsinchu, Taiwan
E-mail: se10@nspo.org.tw
** Manager, Tatung System Technologies Inc., Taipei, Taiwan
E-mail: hongyu.chen@etatung.com.tw
ABSTRACT: ROCSAT-2, the first remote sensing satellite owned and operated by Taiwan, was
successfully launched on May 20, 2004. Unlike LANDSAT, repeated orbit enables ROCSAT-2
remote sensing capability to acquire any of covered area everyday. Under various constraints of
her agility, imaging capability and multi-requirements from image tasking order, a tool which
may facilitate mission planning is a key element for ROCSAT-2 operators to successfully
execute ordered imaging tasks. Such a need drives NSPO and Tatung System Technologies Inc.
to develop Programming Management System (PMS) in the Image Processing Center (IPC) to
assist both mission programmer and operator’s daily operation. PMS serves as a decision
supporting tool to assist ROCSAT-2 imaging acquisition plans in the following two ways: quick
task scheduling and image evaluation capability.
In this paper, ROCSAT-2 daily imaging mission flow chart from receiving tasking order to
satellite command load uplink is described. Detailed functions and operation procedures for
PMS are demonstrated along with a mathematical model for proposed optimal scheduling
process.
1. INTRODUCTION
ROCSAT-2 was successfully launched on May 20, 2004. Unlike LANDSAT, repeated orbit
enables ROCSAT-2 remote sensing capability of acquiring any of covered area everyday. Under
the constraints of her agility, imaging capability and multi-requirements from image tasking
order, a tool which facilitates mission planning is a key element for ROCSAT-2 operators to
successfully execute ordered imaging tasks.
The Image Processing Center (IPC) is a ground segment of ROCSAT-2 for satellite image
processing. In IPC, there are two systems related to image tasking: Programming Management
System (PMS) and Planning & Scheduling System (PSS).
The clients who need ROCSAT-2 images can submit tasking orders directly by Web Service
System (WSS) or send a request to IPC through fax, e-mail or even by telephone. The operator
submits the client’s tasking order by Programming & Production Interface (PPI).
Both WSS and PPI are computer programs to take care of submitted tasking order. WSS is a
web-based program whose target users are those who needs only simple tasking order for
ROCSAT-2 image. PPI is designed for an operator in IPC who handles complex and site survey
tasking order form special clients.
Figure1. Flow chart of ROCSAT-2 remote sensing mission
PMS, a decision supporting system, assists operator to generate ROCSAT-2 daily imaging
acquisition plans. First, PMS quick task scheduling capability allows operator to formulate and
check feasibility of imaging plans and acquires optimal one from those plans. Meanwhile, PMS
calls PSS to calculate desired satellite attitude based on imaging time and target area under the
constraints of ROCSAT-2 maneuver, agility and SSR memory. Second, such a capability also
allows operator to evaluate received image and rapidly issues a new task for the same area if the
image was not acceptable due to its quality or weather condition.
Both PMS and PSS focus on solving the problem caused by confliction among tasking orders
the other satellite resource constraints are checked by Mission Planning Scheduling System
(MPSS). MPSS deals not only with ROCSAT-2 remote sensing mission but also scientific
mission. MPSS generates a sequence of commands to satellite through TT&C. The flow chart of
ROCSAT-2 remote sensing mission is shown in Figure 1. Note that MPSS is not part of IPS but
a subsystem of Mission Operation Center (MOC).
