UNIVERSITI TEKNOLOGI MALAYSIA - FKE - UTM

8processing and digital control machinery together to realize the digitization,network and automatization of agricultural activity. The framework of DigitalAgriculture is composed of the following parts: basic information databases ofagriculture, realtime (or quasi realtime) information collecting system, digitalnetwork transmission system, central processing system (CPS) and digitizedagricultural machinery (DAM). Digital Agriculture stresses the integrativedevelopment of each part. Only when all the parts tie closely and developcooperatively, they can construct Digital Agriculture. Any part or several partsdeveloping separately can’t be called Digital Agriculture.Figure 2.1 Frame work of Digital Agriculture2.3 The GPS SystemThe current GPS system is consist of 3 major segments. These are spacesegment (SS), control segment (CS) and the user segment (US). There are 24satellites which are orbiting the Earth around 20,000 kilometers above us is thespace segment. These satellites are travelling at speeds of roughly 11,000kilometers per hour. GPS satellites are powered by solar energy. Small rocketboosters are installed on the satellites so that they are moving on the correct path.GPS satellites circle the Earth twice a day in a very precise orbit and transmitinformation to Earth. GPS receivers using these information and use triangulationto calculate the user’s position. So, the GPS receiver compare the time when the