Intervisibility Consistency Analysis Of Multi-resolution Terrain Data

Data VV&C is an important method to guarantee data quality and improve data credibility.As a widely recognized key indicator in VV&C,consistency was used to evaluate and measure the degree of information uniformity between one or more datasets.Terrain data is a kind of common and important data in modelling and simulation,but Data inconsistency means there exists contradictions and conflicts among data elements.But terrain data quality researches in domestic mainly focus on data precision and integrity,and there is almost no research on the consistency of multi-resolution data.Considering that intervisibility is used widely in each process in combat including surveillance,reconnaissance,communication and attack which is an attribute related to application directly.Besides,intervisibility determination is a basic and common problem in M&S.So intervisibility consistency is chosen to be an important indicator to analyze multi-resolution terrain data in this paper.But nearly all traditional intervisibility algorithms ignore the effect of earth curvature,and strictly speaking their calculation principle is not correct in a mathematical sense.Under the background of above problem,at first a new algorithm based on GCS which is wide in application and high in accuracy is proposed to determine the intervisibility.By judging whether there exists intersection between LOS and terrain curved surface,intervisibility consistency is determined.And the terrain surface is reconstructed using the bilinear interpolation method.This algorithm guarantees the accuracy from mathematic,at the same time,GCS is introduced to reduce the intervisibility error caused by earth curvature.Then two indicators are chosen to measure visibility consistency of multi-resolution terrain data.Finally,based on real terrain data from Germany Aerospace Agency,experiments are designed and conducted.This algorithm is used to calculate intervisibility consistency of multi-resolution terrain data,and the relation curve between resolution and intervisibility consistency is got which can reflect quality and credibility of terrain data in some sense.Experiments reveal that:(1)Intervisibility consistency does not necessarily scales monotonically changing with terrain resolution.Under some condition,there exists low resolution data whose consistency is better than high resolution.(2)If resolution of terrain data is higher than a specific value,the degree of topographic relief will have little influence on intervisibility consistency.It can be easily found that when resolution is higher than 100 m,the intervisibility consistency curves of those two terrains are almost entirely coincidence with each other.(3)When data resolution is higher than 100 m,no matter for the flat terrain Dataset N or for the volatile terrain Dataset S,lowering resolution is an effective method to reduce the computing time and the intervisibility error caused by this is always less than 1.5%,but if resolution is lower than 100 m,the influence of lowering resolution on computing time will be small.(4)The generation range of z value has some influence on intervisibility consistency,but general trend is not influenced.