An indoor visual positioning system is proposed, which using four or more LED ceiling lamps and a mobile phone. A 4*4 photodiode array is attached to the mobile phone to receive the three-dimensional coordinates of the LED lamps via visible light communication, and the front camera of the mobile phone is used to receive the high resolution image of the LED lamps. The mobile phone’s three-dimensional coordinates can be determined by matching the spot information and three-dimensional coordinates of the LED lamps with the image information provided by the mobile phone. An improved collinear equation model is proposed to build the mapping relationship between the three-dimensional coordinates of the LED lamps and the image information acquired by the front camera. A semi-physical simulation has been conducted and analyzed. The positioning scheme is proved to be valid and the positioning accuracy is up to decimeter level.
Ground based regional augmentation systems is unable to cover regions such as the oceans, mountains and deserts. And its signal is vulnerable of building block. Besides, its positioning precision for high airspace object is limited. To settle such problems, a Differential augmentation method based on troposphere error corrections using aerostat reference stations is proposed. This method utilizes altitudes of mobile station and aerostat station to estimate troposphere delay errors, resulting in troposphere delay difference value between mobile stations and aerostat reference stations. With the aid of satellite navigation information of mobile stations and aerostat station and both troposphere delay difference values, mobile stations’ positioning precision is enhanced by eliminating measurement errors (Satellite clock error, Ephemeris error, Ionospheric delay error, Tropospheric delay error) after differential. It is showed by simulation test that aerostat reference station Differential augmentation method based on tropospheric error corrections improves 3D positioning precision of mobile station to within 2m.