Low-Cost UWB/SINS Integrated Positioning System For Indoor Long And Narrow Environment

Indoor Real-time Location System(IRTLS)can track the objects or persons that need to be located in the room in real time.It usually displays the location information in real time through the upper computer or client.It is widely used in warehousing,logistics and dangerous area monitoring.With the development of large data in recent years,location information is regarded as an important data.More and more reflect its practical significance,and continue to receive attention.In indoor positioning,the combination of Ultra Wide Band(UWB)and Strap-down Inertial Navigation System(SINS)can be used as an important solution in engineering practice because of their complementary defects,mutual advantages,high positioning accuracy and relatively low cost.However,all kinds of schemes to improve UWB positioning accuracy either focus on dealing with small errors such as jitter and noise,or on dealing with gross errors caused by UWB Non-Line of Sight(NLOS).For indoor harsh environment,the study of UWB medium errors caused by multipath effect is less.As the most common and important structure in indoor environment,long corridor is a typical harsh environment seriously affected by multipath effect.Because corridors are usually surrounded by strong reflective concrete walls,UWB ranging errors usually expand from less than 10 centimeters to 230 centimeters,or even larger.Conventional UWB algorithm is difficult to obtain high-precision positioning results,while the narrow environment is not conducive to the layout of the required base station(Anchor),and the layout of the base station also has a greater impact on the positioning results,making positioning errors.The gap widened further.On the premise of low accuracy of UWB,SINS with accumulated errors over time can hardly achieve the effect of improving positioning accuracy.Without better initial value or calibration value provided by UWB,SINS will even be completely ineffective,which makes the UWB/SINS integrated positioning system basically inapplicable in the narrow corridor.In view of the above problems,this paper develops an indoor real-time positioning system for narrow environment.The location tag(Tag)can be located more accurately through fewer base stations.Then,the SINS sensor can achieve higher positioning accuracy by combining with strapdown inertial navigation system.The SINS sensor chooses inertial transmission based on Micro Electro Mechanical Systems(MEMS).Sensors,such inertial devices are small in size,light in weight and low in cost.The accuracy corresponding to these advantages is not particularly high.They can be compensated by combined system,which is a better choice in engineering.The main contents of this paper are as follows:(1)The location error of UWB in harsh environment is deduced mathematically,and a new UWB geometric positioning model is proposed based on it.Then the positioning results are optimized by Newton iteration method.Experiments show that this optimization method can improve the positioning accuracy and stability of UWB in narrow environment,but there are some defects that the positioning results may diverge.(2)Aiming at the defect of the new positioning model,the method of combining SINS with SINS is used to remedy the defect.For the problem of inaccuracy of magnetometer when SINS is realized by using inertial devices of MEMS,a method of Strapdown derivation based on relative relation is proposed.The position of Strapdown estimation can be obtained by UWB without using magnetometer,and then by Kalman filter.Loose combination and judgment pool are used to judge whether the location points diverge or not.If divergence occurs,strapdown estimation is used to replace the divergent location points.(3)In order to verify the accuracy of the above algorithms,a real-time positioning system including hardware platform and server is designed and implemented.Through the final test,it can be found that the UWB/SINS integrated positioning system has greatly improved compared with the traditional positioning method,and can basically distinguish the exact location of the points to be measured in the corridor,and the integrated system is relatively new single UWB positioning system.The model has also been significantly improved.The combined positioning system in this paper embodies the advantages of high precision and low cost of UWB/SINS integrated positioning system,and in a narrow environment,it can achieve better positioning effect than the original method.Compared with the traditional location algorithm,this system has great advantages in corridors,corridors,mines,tunnels and other narrow and harsh channel environment.Minimizing the cost is also of great practical significance in scientific research and engineering.