| In this thesis,the network-based technique is used to obtain the position of an mobile phone(MS).The MS is not involved and no changes have to be made to the MS to use this technique.According to the characteristics and advantages of the Global System for Mobile Communications(GSM),a novel architecture of location system is proposed to detect the GSM signal.The main research content is as follows.In recently mobile localization techniques,most approaches are passive to measure the signal from mobile phone and can't detect the standby mobile phone.In this thesis,an effective approach based on handover technique for triggering the GSM signal is proposed to make the phone transmit the frequency hopping signal which can be established without user interaction.According to mobile phone's hopping characteristic,the technique makes use of the increased bandwidth of frequency hopping waveforms and processes the signal with time delay estimation.The results show that In case of E-GSM 900 systems,up to 35M of bandwidth can be used which leads to the estimation errors range in a few meters and the multipath resolution can be improved with increased bandwidth of frequency hopping.In this thesis,the hardware and software systems are designed to complete the mobile phone location.The openBTS system and USRP are used to trigger the mobile phone signal.At last,the time delay estimation is made separately with narrow signal and frequency hopping signal.The results show that it's a high application value for mobile phone location to research the frequency hopping technique. |
