(a) Field of the Invention
The present invention relates to a position measuring apparatus and method, and more particularly, to a position measuring apparatus and method using an image sensor.
(b) Description of the Related Art
In general, a global positioning system (GPS) is used to measure the position of an object. In a GPS method, the distance from a GPS satellite to a measurement object is calculated by receiving positioning information from the GPS satellite and measuring the time taken to receive the positioning information. The distance from one GPS satellite is equal at any location on the globe as far away as the GPS satellite. If three or more of such information, that is, trajectory information (longitude and latitude) and distance of three satellites are obtained, a point where virtual spheres formed by the three GPS satellites meet is created, and this point serves as the position of a measurement object. However, an error may occur in such GPS-based position information depending on the accuracy of positioning information provided by the GPS satellites and the accuracy of current time information required for calculating the distance from the GPS satellites. The error can be several tens of meters. Another disadvantage is that no GPS satellite signal can be received indoors.
To overcome these disadvantages, the position information of a base station to which a mobile terminal is connected or the position information of a connection in a wireless LAN such as WiFi may be used. However, one of the major drawbacks of such a position information service using radio waves is that it is difficult to provide three-dimensional position information. In other words, information about the presence of a measurement object in a certain building can be acquired; however, information about on which floor or in which room the object is located is hardly obtained. In order to overcome these disadvantages, a position measurement technique based on position information by using the visible light wireless communication technology has been proposed. In this case, position information about a measurement object may even include details like the floor, room, etc. of a building where the measurement object is placed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
USPTO Backgrounds
USPTO Backgrounds