Handheld Gps Receiver

In the thesis, a detailed scheme has been discussed for designing portable GPS receivers, which, based on the principle of Global Positioning System (GPS), are widely used nowadays in traveling, navigations, land surveys and many other areas.A general principle of GPS and its applications are introduced first. Then, based on market investigations, the structures of portable GPS receivers are developed.The hand-held GPS receiver designed uses an Original Equipment Manufacturer (OEM) board as the module to acquire original positioning signals. A microprocesser is used to process the data, and then, display the information in an LCD screen.The functions of the receiver are versatile. Except to show the positioning locations in digital or graphical modes, the device also has abilities to store and playback 15 routes previously recorded.Considering the portable device asks for low power consumptions which are often vital to contemporary portable electronic system designs, the paper depicts the power management and low power design of the GPS receiver.Because of random noises in the GPS data, which influence the positioning precision, a method of Kalman filtering has been used in processing the observation data and accomplishing the simulation. The results show that the precision of positioning is improved.Receivers base on a DSP (Digital Signal Processing) microprocessor are presented in order to fit requirements of high speed operation in real-time filtering and GIS (Geographic Information System) technique.The hardware structure of the DSP device is also schemed briefly.