Development of Wireless Electric Field Mill for Atmospheric Electric Field Observation

Abstract

Rotating-vane electric field mill (REFM) IntroductionIt is a well know fact that the knowledge of ambient electric field strength provides valuable information about the lightning incident. Observation and measurement of atmospheric quasi-static electric field is able to provide lot information regarding to thunder storm activities, lightning incidence, aerosol presence in air, radioactive pollution, indication of earthquakes, and parameters of the solar wind [1]. According to Jacobson [2] when the electric field strength due to the presence of clouds is over the limit of ambient air insulation threshold lightning will occur. The range generally is from 1 kV/cm to 4 kV/cm or within an average of 3 kV/cm.In order to measure the ambient electric field strength or potential gradient various methods have been introduced [3]; one of which is the electric field mill (EFM) technique. However, in certain circumstances the rotating-van electric field mill (REFM) is generally being used as an instrument for observing the cloud electrostatic phenomena. The principles of operation and location determination of REFM are being widely studied by many authors [4][5][6][7][8]. Typically REFM has to be coupled with a personal computer (PC) on site in order to collect and store data from the instruments [9]. This condition demands costs on installation of computer and data logger system on site, as well as manpower to collect data from REFM sensor location. Furthermore, this also raises safety issues on the instruments and the computer system. Therefore, there should be a solution to be introduced to overcome this problem.Since most of the sensors located far apart in remote areas, one of the competent technologies that can be applied to this problem is by using wireless data transmission system to transmit data from the REFM to a computer in a data centre building via internet protocol and web-base programming.Global system for mobile communication (GSM) is the most suitable technology to be applied. GSM is on the market for a long time and it is offering varieties of features and having users of more than 5 billion people, more than 80% of earth population. In addition, GSM is offering low cost ownership and worldwide coverage as this technology has been existed for more than 20 years [10]. However, GSM has several shortcomings, which it is unable to perform transmitting and receiving data concurrently and the unsatisfactory real-time ability [11].With the shortcoming of the 2G network, then it further develops into 2.5G, which is the