| Nowadays,the problem of China's population aging is getting worse.With the growth of empty nesters,old people increasingly tend to living in nursing institutions for retirement.However,the traditional institutional nursing system cannot provide real-time nursing for the elderly,making the intelligent nursing become an inevitable trend.The intelligent nursing refers to using Internet of Things,wearable technology and mobile technology to provide the elderly with real-time,efficient and intelligent services.In this model,accurate and real-time information on the location of the elderly in the nursing home is the basis for service development.Therefore,it is necessary to develop a positioning system with high precision,high capacity,high dynamic performance and high reliability for the nursing home.In response to the above requirements,the positioning technology based on Reverse-TDOA measurement is studied.In order to improve the positioning performance,the thesis studies the high-precision wireless time synchronization technology and data processing technology.In addition,the overall architecture of the positioning system is presented,and the hardware are established Finally,an experimental platform is built to verify the effectiveness of the positioning system.The main tasks of this thesis can be described as follows:1.Comparing the existing personnel positioning technology and principle,this thesis selects the UWB positioning technology and the positioning mechanism based on TDOA measurement.Considering that hyperbolic equations established in TDOA positioning are difficult to solve,the Chan algorithm is proposed to obtain the initial value and the Newton iteration is employed to obtain better position estimation results.The estimated error of the Newton iteration can reach up to CRLB.2.For the requirements of high-precision time synchronization in the positioning system,the synchronization accuracy of the Reference Broadcasting Synchronization(RBS),the Timing-Sync Protocol for Sensor Networks(TPSN)and the Flooding Time Synchronization Protocol(FTSP)are theoretically analyzed and simulated.TPSN is selected as the time synchronization method of the system,which can ensure higher synchronization accuracy and reduce the computational complexity.In order to solve the problem that the deviation of positioning data is large in the process of dynamic positioning,track correction algorithm is studied,which can remove the bad data online and improve the filtering precision.At the same time,it improves the reliability of the system.3.To meet the needs of the nursing home,a method based on TDOA passive measurement is put forward and the overall scheme of the system is designed.In detail,the overall scheme of the system includes the design of system framework,system networking,positioning workflow and the hardware and software module of positioning equipment.The intelligent nursing home personnel positioning system was developed,which can achieve high-precision,high-capacity and high-dynamic positioning effects.Above work has been verified in terms of static and track position measurement of personnel,system positioning capacity test and electronic fence cross-border alarm function test under complex indoor environments.The results indicate that the accuracy of static positioning is better than 15 cm,the accuracy of dynamic positioning is better than 20 cm and the positioning capacity is greater than 200.In addition,the electronic fence crossing alarm function is implemented,which plays a significant role in solving the problem of intelligent safety guarding protection for the elderly in nursing homes. |
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