Deployment is complete, that paragraph of time beidou satellite navigation system to global customers to provide all-weather, all-day, high-precision positioning and navigation services, location-based services once again become a hot spot, on the tuyere location service in addition to the big dipper, and is suitable for indoor high-precision positioning of UWB technology, as well as by the UWB technology on the basis of various positioning service plan,

Cloud cool technology over the years committed to the power plant security, power plant through the cloud and cool know when UWB personnel positioning system, a frequently asked question is "how positioning accuracy", this article will focus on UWB positioning precision of the problem is,

Outdoor GPS and beidou positioning and indoor UWB, bluetooth and other location has a different nature, which both MEO, IGSO and GEO three tracks for more accurate positioning, and UWB positioning is based on TDOA or TOF range to achieve precise positioning, in the previous article: "why the same UWB positioning system positioning precision is not the same?" We have done a lot of two algorithms in explanation, there would not be in here,

Beidou positioning simulation figure

Theory of UWB precision can achieve millimeter level even micrometers, but are different in the actual deployment, which affected the accuracy of UWB positioning because basically has the following kinds:

1 sensor layout way influence on positioning accuracy

The positioning precision in the actual calculating process, the number of sensors increase means the increasing of the redundant information, abundant redundant information can further reduce the positioning error, but the positioning precision is not best growing as sensor, after the sensor increases to a certain number, continue to increase the sensor's contribution to the positioning accuracy is not large, and the increase of sensor number means that the cost of the equipment, so how to find a balance between sensor number and location accuracy and rationally designed UWB sensor is the focus of the studies of position precision effect of the sensor layout,

2 the influence of the multipath effect

UWB UWB positioning signal in transmission process will be affected by the surrounding environment such as wall, glass and desktop indoor items such as reflection and refraction, produce multipath effect, the signal delay, the change of the respect such as amplitude and phase, to produce energy attenuation, signal-to-noise ratio drops, lead to the first of the signal is not direct signal, cause ranging error and positioning precision is also down, therefore, effectively inhibit the multipath effect can improve the positioning accuracy, the inhibition of multipath method mainly include MUSIC, ESPRIT and edge detection technology, such as

3 NLOS effect

Spread line-of-sight (LOS) is to ensure that the first and premise condition of signal measuring results are accurate, when mobile positioning between target and base station can not meet the conditions, the transmission of signals can only be done in refraction and diffraction under the condition of non line-of-sight, first at this time of the pulse of time do not represent the real value of TOA and AOA did not start the first of the direction of the pulse real value, this will cause certain positioning error, the method to eliminate error of non-line-of-sight Wylie method and elimination method,

4 human influence on positioning accuracy

The main components of the human body is water, water for UWB wireless pulse signal with strong absorption, result in attenuation of signal intensity, there is a deviation distance information, influence the final positioning effect,

5 signals through weakening the influence of

When any signal through the wall and other entities will abate, UWB is no exception, when UWB through ordinary brick wall signal will weaken nearly half or so, the change of signal transmission caused by penetrating the wall time also will affect the positioning accuracy,

Various obstructions on the influence of UWB:

(1) solid wall: see the solid wall of the shade will make UWB signal attenuation 60-70% localization accuracy error up 30 centimeters, see two or more than two see solid wall block, will be prevented UWB positioning,

(2) the steel plates, steel uptake of UWB pulse signal is very serious, will be prevented UWB positioning,

(3) : glass shade for UWB positioning precision is not too big effect,

(4) board or cardboard: general board or cardboard thickness of 10 centimeters or so not much impact for UWB positioning accuracy,

(5) pole or trees: pole or written sheltered needs to see the distance distance between the base station or label them, and whether the base station and the relative distance of the tags are very small, for example, the base station and locate the label distance of 50 meters, right in the middle of the two poles or trees, 25 meters, the shade is no big effect, such as close to the base station or the label distance less than 1 meter, the influence is very big,

Decorate in the different scenarios, how both can input and precision is obviously reflects the positioning of the solution, also spent one hundred thousand yuan, a service provider can achieve the cm-level positioning, while others can only achieve decimeter level, there is the gap between hardware, but the main one is that the demand for the industry and the construction of industry experience, with a better understanding of the cloud and cool technology focused on electric power industry, power industry experience for many years to personnel positioning and the actual business requirements of the perfect fusion of power plant, power plant is solve the personnel safety, personnel management,