Multi-User Online Map

Abstract

Map service has become an important element in many applications for daily convenience. Apart from Google Maps that provides navigation function for route planning, maps services are implemented in many popular apps in Hong Kong. For example, in OpenRice, KMB&LW and Google Photos, map services are implemented for finding a restaurant, the nearest bus stop, or plot the location on photo taken for recording a travel journal. However, these applications can only help single user to find the route. When we are having a gathering with friends, we usually meet at the destination and most of the time some people will be late. The reasons for being late can be losing the way or traffic jam. And it is hard for us to track their position to guide them to the destination, and to estimate how long will be taken to meet. Sometimes, people may have different understandings on the destination, such as the exits of a shopping mall, it is hard to explain the location when they are not familiar with the place. This project aims to develop a mobile application to share locations with our friends. Different from the Google Maps, locations of every user can be shown on the same map, and it is unnecessary to explain where you are anymore. A route will be suggested for you to meet your friends. The application will record your moving speed, and it will compute an estimate time that how long you will need to meet your friends. A GPS receiver in Android Device will be used to detect user location and current moving speed. Making use of the detected multiple satellites signals a location can be determined, and velocity can be further determined from the frequency difference between satellite and receiver, which is known as "Doppler Shift". The performance of GPS Doppler shift velocity was proved with a very high accuracy. Due to the limitation in update rate, an accelerometer that is a component in most Android devices can be used for instantaneous acceleration determination. GPS is often unavailable for indoor location. Accelerometer is feasible for monitoring device movement in acceleration and orientation, the availability in collecting instantaneous acceleration data can be served as an alternative of the insufficient rate of GPS receiver. Accelerometer velocity can be further determined from the acceleration data. Combination of GPS and accelerometer velocity determination will be served as the alternative for velocity determination. Meanwhile, the acceleration can be generated by cheating, it achieves a high value under shaking of device. To eliminate cheating behaviour, activity recognition will be applied to discard the acceleration of non-walking activity. Making use of simple GPS receiver and accelerometer, which are the basic components in most Android device, we can perform the location function and speed function. Exchanging users’ location information on a map enhances the efficiency to let the others know user’s position. Estimating time to meet based on current speed helps users to predict what time they will meet.