Increase a standalone GPS positioning accuracy by using a proximity sensor

A high accuracy guidance system is important for many applications such as precision agriculture. The current RTK-GPS has accurate in unit centimeter but has high cost and using high frequency signal to transmit between GPS devices and reference devices requires the permission from The National Telecommunications Commission (NTC) in Thailand. A regular GPS receiver has lower cost but has accuracy about unit meter. As a result, we introduce the use of the known location as the auxiliary information to increase the accuracy of the positioning system. When a vehicle travels near the known location, its position will be calibration. The positioning errors from the GPS are computed and used to adjust the GPS data at the next unknown location. This paper investigates the use of the simple linear estimate for the ease of implementation and reliability in the field work. Our result shows that the simple last known error value is the best estimate.