Laser full-echo track subdivided processing method through combination of digital image aerotriangulation

Abstract

The present invention provides a laser full-echo track subdivided processing method through combination of digital image aerotriangulation. The method comprises: extracting the wave crest elevation value of each moment of the laser radar track waveform to realize the obtaining of the elevation value of a laser radar track subdivide area; and establishing a ground elevation model relative to the laser radar track and a simulation waveform to obtain the relative elevation information of a stereopsis corresponding to the laser radar track and match the laser radar track waveform and the simulation waveform to correspond the elevation value of the laser radar track subdivided area to the pixel of the stereopsis so as to realize the conversion from the relative elevation information of the stereopsis to an absolute elevation information, obtain the absolute elevation value of the pixel of the stereopsis and solve the problem that the accurate elevation value of the pixel of the stereopsis cannot be obtained due to the sizes of the laser radar track area and the pixel of the stereopsis are not matched. An elevation value is taken as an auxiliary elevation control point of the digital image aerotriangulation to effectively improve the precision of the surveying and mapping of topomap of the satellite camera measurement.

Description

technical field [0001] The invention relates to the technical field of laser radar measurement, in particular to a laser full-echo footprint subdivision processing method combined with digital image space three. Background technique [0002] Traditional topographic maps are mainly surveyed and drawn topographic maps by means of aerial photogrammetry. With the development of aerospace technology, computer technology and information processing technology, satellite photogrammetry has become an important way of topographic map surveying and mapping. [0003] The current satellite photogrammetry technology surveys and maps 1:50,000 and 1:10,000 topographic maps or repairs and surveys 1:25,000 topographic maps. The elevation accuracy requirements of different scale topographic maps are shown in Table 1. The elevation accuracy is 0.35m for flat land and 1.2m for hilly land. [0004] Table 1 Requirements for elevation accuracy of different scale topographic maps (unit: meter) [...

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Problems solved by technology

[0008] like figure 1 As shown, for a general spaceborne lidar, the center of the laser beam is measured H, and the inclination angle of the deviation from the apex is Terrain surface inclination angle β, divergence angle θ, and satellite orbit altitude 500km, the limit error of laser ranging caused only by the influence of surface inclination when β=15° (hilly land), when θ=0.06mrad, the laser ranging error reaches |ΔR|≈1.29m (1σ); according to the current satellite orbit determination, attitude determination and platform stability control level in China, the orbit height is 500km The plane position error is about 1.13m, and the elevation error is 0.30m under the condition of 15° hilly surface; comprehensively considering the influence of the ranging error in the laser footprint and the error of orbit determination and attitude determination, it is impossible to obtain a higher-precision topographic map

[0009] The distance measurement accuracy of spaceborne lidar can reach 0.1-0.2m. Considering the influence of atmospheric environment and other factors, the elevation measurement accuracy will reach 0.3-1.0m in the case of plain and hilly surfaces, although the elevation of traditional satellite photogrammetry has been significantly improved. Measurement accuracy, but limited by the divergence angle of the lidar, equipped with a satellite platform of 500-600km, the footprint of the lidar is usually tens of meters, and within the footprint of tens of meters in diameter, it is obviously impossible to accurately describe it only by the average elevation in the footprint Variations in local topography

The main disadvantage of using multi-beam full-echo lidar technology to assist aerial triangulation is that the spaceborne laser footprint is large, and it is impossible to directly extract the precise terrain relief information at different positions in the laser footprint, which affects the plane elevation resolution of the laser spot footprint. As a result, the accuracy of topographic mapping in photogrammetry cannot be improved

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