Method and system for reducing position information measurement error of non gps mobile communication terminal

A method for reducing a position information measurement error of a mobile communication terminal which is not embedded with a GPS(Global Positioning System) and a system therefor are provided to calculate position information of the terminal by using RTD(Round Trip Delay) of reference PN(Pseudo Noise), if only the reference PN is included in a downlink wireless environment list, thereby reducing a position information measurement error. A terminal(210) provides a location based service as a non GPS device. A base station transmitter(220) collects PSMMs(Pilot Strength Measurement Messages) including pilot PN phase information, pilot strength information, and PN. A base station controller(230) configures RTD from CDMA(Code Division Multiple Access) target one way delay of downlink wireless environment for reference PN. An MSC(Mobile Switching Center)(240) receives an RMP(Radio Measurement for Position Response) message, and includes a downlink wireless environment list in an ISPOREQ(Inter System Position Request Invoke) message. A PDE(Position Determination Entity)(250) receives the ISPOREQ message, and calculates position information of the terminal(210) by using the RTD if only the reference PN is included in the list.