Earth Observation System
Vinai Vorrawat
National Research Council of Thailand
196 Pahonyothin Road, Bangkhen, Bangkok 10230, Thailand
Keywords: Earth, observation system
Abstract: The JERS-1 observation system can be divided into space segment and ground
segment the space segments is JERS-1 satellite. The ground segment includes the tracking and
control system a data acquisition and processing system. JERS-1 can carry two pieces of
observation equipment, the synthetic aperture radar (SAR) and optical sensor (OPS) which
composed of two radiometer the visible and near infrared radiometer (VNIR) and short wave
infrared radiometer (SWIR) JERS-1 composed of these observation equipment. Mission data
recorder (MDR), Mission data transmission (MDT) and subsystems for solar paddle, attitude
and orbit control and thermal control. The satellite revolves in 96 minutes around the earth. It
makes 15-1/44 revolutions per day and returns to the same orbit every day.
1. Introduction
When 8 GHz band receiving subsystem is used to receive a JERS-1 signal and checking the
operation of a receiving system the subsystem is operated either through remote control by an
antenna subsystem or local control by the controller of a 8GHz band main receiver. The
subsystem does not require much complicated operation and can be set to most operating modes
of the subsystem through remote control, enabling the subsystem unattended during normal
operation.this paper descries outlines of the operation procedures for startup of the whole
subsystem, receiving the signals and stopping power base on fig 1 for details refer to the
operation introduction in relevant equipment. 8 GHz band main low noise The status can only be
checked by the antenna subsystem.8 GHz band frequency down converter (X-D/C) (S/X -D/C) set
the power on/off control switch to remote. The X-D/C status can be also checked at the antenna
system. 8 GHz band main receiver (X-RX). The normal operation mode is remote (remote control
from the antenna subsystem.) 8 GHz band main receiver (X-RX). The normal operation mode is
remote (remote control from antenna system) . The following element should preferably be
monitored during reception a reception level (AGC level.) angle error voltage. Lock status and the
X-RX status can be also checked at the X-RX status can be also check at the antenna system. 8
GHz band receiving system. The receiving subsystem operations check using the X-cal before
reception is not necessary unless otherwise specified. However recommences that the check be
perform as it is an effective way of ensuring the reception.
X-LNA : 8 GHz Band Low-noise amplifier
X-D/C : 8 GHz Band frequency down converter
X-RX : 8 GHz Band main receiver
- These procedures may not be performed.
Figure 1 Flow Chart Overall Operation Procedure
2.Operation
Table 1. Lists the operation precautions for each equipment
| No. | Equipment name |
| 1. | 8 GHz band low-noise the status can only be checked by the antenna subsystem. |
| 2. | 8 GHz band frequency down converter (X-D/C) (S/X-D/C)
- Set the power ON/OFF control switch to REMOTE
- The X-D/C status can be also checked at the antenna subsystem. |
| 3. | 8 GHz band main receiver (X-RX)
- The normal operation mode is REMOTE (remote control from the antenna
subsystem)
- The following items should preferably be monitored during reception
- Reception level (AGC level)
- Angle error voltage
- Lock status
- The X-RX status can be also checked at the antenna subsystem. |
| 4. | 8 GHz band test equipment (X-CAL)
- Before reception, check that the test signal output is OFF.
- The status can be also checked at the antenna subsystem . |
| 5. | 8 GHz band receiving subsystem
- The receiving subsystem operation checks using the X-CAL before reception
is not necessary unless otherwise specified.
- However, NEC recommends that the check be performed, as it is an effective
way of ensuring the reception. |
