Localization is one of the core technologies of indoor surveying and mapping services. To achieve an accurate indoor navigation and positioning

many indoor navigation and positioning technologies have been introduced. Given that visual sensors can generate an abundant amount of information at low cost and can be easily implemented

the space navigation and positioning method based on vision sensors has become a research hotspot. This paper proposes a robust method for measuring the mobile platform position measurement based on the coding graphic images that are captured by a monocular vision sensor.

First

a series of coding graphics for the positioning of the carrier are designed. Coding graphics can be accurately identified through contour matching

and the coordinates of the center of graphics can be obtained by means of moment calculation and coding matching. However

due to the shooting angle

the coding image is deformed

thereby resulting in the residual errors of the image coordinates. Second

the Tukey weight factor model is used to calculate the weight according to the residual of the observed value. The value with a residual error of less than 1

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the value with a residual error ranging from 1

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to 2

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will be used with reduced weight

and the values with a residual error outside the range of 2

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will be suppressed. Third

the space resection methods based on Tukey and unit weights are adopted and used to calculate the position information of the mobile vehicle. Finally

experimental environments are then built

where 22 coding graphics are randomly pasted on the wall

and the coordinates of the coding graphics with accuracies of greater than 1 cm are measured by the total station. Four groups of images are captured

with each group having 9

12

11

and 17 available coding graphics of each group.

The experiment results indicate that the proposed methods (based on unit weight and Tukey weights can be used to calculate the position of mobile carriers in a room. The method based on Tukey weight obtained better results and improved the plane and elevation accuracies by 29.76%–49.42% and 29.17%–74.07%

respectively.

In general

the coding graphics designed in this paper can be accurately identified and positioned

the Tukey weight factor model can effectively identify the observed value residuals

and the space resection method based on the Tukey weight factor model can be used to calculate the position information of the vehicle and obtain better estimates. Therefore

the proposed method can provide high-precision navigation and positioning measurement services for indoor space mobile carriers.