I Introduction
Location services are closely associated with daily life. Outdoor GPS has been able to well meet people’s needs, but indoor positioning has not formed a stable and mature solution [1], [2]. Indoor positioning on account of wireless sensor network has mainly two methods based on ranging measurement and not based on ranging measurement. The latter is easier to implement, but the positioning degree of exactitude is usually poor [3]. Since former is relatively complex, but the degree of exactitude is higher, the method on account of ranging is more repeatedly exerted [4].