NOVAA Weather satellite WWW Server at UKM
Y.Y.Meng, M.Ismail, Z.A.Abdual Rashid ad O.A.Karim
Faculty of Engineering
University Kebangsaan Malaysia
43600 UKM Bangi
selangor Darul Ehsan, Malaysia
Tel: 603-8296322 Fax; 603-8296146
E-mail:cyymeng@pl.jaring.my
Abstract
A ground station has been installed at Universiti Kebangsaan Malaysia (UKM) to receive the VHF signal form the united state National Oceanographic and Atmospheric Administration(NOAA) Low Earth Orbiting Satellite (LEO) werther satellite series. The satellite signal was received and decoded as image which was displayed on computer screen in the form of visible light, infra-red or the combination of both. The image file is then processed into the UKM campus network. In order to share the weather information on-line, a web-site server is now being set-up in UKM ( http://comsat.eng.ukm.my ).
Introduction
NOAA is a United State government organization which missions are to describe and predict changes in the earth's environment, and conserve and manage wisely the nation's coastal and marine resources to ensure sustainable economic opportunity[1]. There are two types of NOAA's operational weather satellite: geostationary operational environmental satellites ( GOES) for short-range warning and " now-casting " and polar-orbiting satellites ( POES) for longer-term forecasting [2].the NOAAs polar orbiting satellite transmit signals on frequencies in the range of 136MHz to 138MHz.
The world wide Web server which has been installed will be used to relay the natioal weather information to public. The main objective is to create a digital library, which contains information about the current and past satellite images from NOAA's Polar-orbiting Operational Environmental satellite. The WWW homepage is designed to provide on-line easy access to the satellite data. It allows users to search the satellite data databases, view the real-time or historical satellites images and download the weather image for further processing analysis. The satellite data, which is in the form of image, consists important information for weather analysis, forecasting, climate research and predication
UKM NOAA Ground Station
UKM ground station is located at Faculty of Engineering at 3009' North, 101049' East which is close to the equator. It can be categorized into hardware an management software.
i. Ground Station Hardware
fig. 1 shows the block diagram of the ground station [3]. The heart of the ground station is the Timestep© pro-scan weather satellite receiver. Basically , it consist of an antenna, FM receiver, and a decoder card which is installed in the computer to display the image. the receiver operating range is from 137.30MHz to 137.85MHz. the antenna was mounted such that a clear line of sight path to the North and south horizon was achieved and it was positioned away from sources of interference. It is non-directional antenna, which is, consist of two element crossed dipole and crossed reflector with a gain of 8dBi. The dipole-reflector spacing has been optimized for maximum signal combined with nearly horizon to horizon response. It is designed to intercept the small amounts of RF energy.
Figure 1: Block diagram of the ground station hardware
A Pentium-60MHz computer equipped with decoder card and running on Windows95 platform is used. In order to run Timestep software under Window95 platform to do multitasking, the display adapter of the computer must support the direct-draw overlay. In this case, S3 Trio 64V+ display adapter is used in ht computer. After switching on the Timestep receiver, it starts scanning. The receiver will stop scanning when it detects the satellite signal. The speaker will indicates this by the sound 'tic-tic' .
