A local positioning system based on VHF band

In this paper, we propose a local positioning system which can provide accurate position estimation using VHF band. The proposed system has much higher accuracy than GPS system using wide bandwidth, low RF frequency. While the GPS uses time information to calculate time of arrival between the transmitter and the receiver, the local positioning system only uses time difference information of arrival among the transmitted signals. Also, we transmits modified direct spread sequence spectrum signal to improve position estimation accuracy. Simulation results show that the proposed local positioning system can provide accurate position information within 0.3m.