TDOA-based Indoor Location Algorithms Design And Implementation

In recent years, with the development of the IOT and pervasive computing,location-based services are increasingly being used in disaster relief, monitoring and care,commercial navigation, smart home other fields. People’s are living in indoorsenvironment. most of time, so indoor location technology becomes a hot topic nowadays.Indoor location technology has the following requirements.Reduce the equipmentcost, try to choose a large number of hardware facilities, best to use existing networkequipment (such as WLAN networks which has been widely covered over shopping malls,airports, office buildings and other public places).The positioning method is implementedentirely in software, without the need for hardware fixing.Easy to use, no need for a greatdeal of preparatory work.The most important thing is to achieve high-precisionpositioning of the target in order to meet the needs of users.In this paper, we fist conduct a systematic study for the indoor locationtechnology,then present a indoor location algorithms based on TDOA without clocksynchronization. The algorithm can take advantage of the WLAN network device. Itreceives a target transmission signal, using the frame synchronization, matched filtering ofthe received signal processing and other processes to estimate the time difference ofarrival in principle of timing error minimization.At last, using the hyperbolic method toestimate target relative coordinates.In this paper, we design a simulation prototype of Indoor TDOA location algorithmswithout clock synchronization. We evaluate performance of the algorithm under theinfluence of noise, timing error, carrier frequency offset, multi-path effects and otherfactors. Finally, we complete experiment measure in the actual environment usingsoftware radio platform Sora. The experimental results show that the proposed algorithmcan provide a satisfied location services with the err less than1meter in the weakermultipath effects conditions, and the err less than3meter in the complex multipathenvironment.