High-voltage power transmission line is an important infrastructure of a country

the breakdown of power facilities may bring huge damage to the daily lives of the people and the economy of the country. Thus

management and monitoring of power f acilities is important. Traditional engineering measures have the drawbacks of high workload

high risk

and low efficiency. Airborne Li DAR can overcome these drawbacks

and cannot be easily affected by environment

making Li DAR an important d evelopment trend for power line measurement. At present

airborne Li DAR is mainly used for the reconstruction of urban areas and natural features; extraction and modeling of power facilities is still in its infancy. The main problems are too much human i ntervention

low accuracy

and lack of continuity. Therefore

this paper proposes a new method based on the analysis of the characteristics of power facilities and extraction algorithm. First

the optimal catenary fitting geometry model of the powerline was o btained based on the powerline characteristics. The nonlinear catenary equation was simplified to linear polynomial form based on the principle of Lagrange polynomial to improve the operation efficiency. Second

the projection direction of the powerline in the XOY plane was determined based on a statistic method. Afterward

the vertical plane that contains the starting and end points and are perpendicular to the power line were also determined based on the characteristic of the end laser point. The distance of all points to the plane as X-axis parameters was calculated and the points corresponding to the Z coordinate values as Y-axis parameters were obtained to determine the optimal plane coordinate system. Finally

the quadratic-polynomial-limited least square method was used to fit the powerlines

obtain the optimal parameters

and generate the final power line model. Experiments on real data showed that the proposed method improved the facility and veracity of powerline fitting. The precision reached ± 1. 740 cm both in the vertical and horizontal planes. The proposed method can quickly fit the powerline and reach a high accuracy

which are significant in the study of 3D reconstruction by Li DAR point cloud.