Potential precision of terrain measurement using space lidars

Abstract

Laser remote sensing technologies are being actively developed and used, for instance, for modelling the terrain of the surface of the Earth, the Moon and other planets of the Solar System. Theoretical aspect of these projects is underdeveloped and not related to the measurement precision assessment. The article studies the calculation of the potential precision of range measurement and presents a method of calculation of the a space-based lidar parameters based on the condition of providing the set range measurement precision. It produces the equations that connect the potentially achievable precision of terrain (range) measurement and the receiver output signal-to-noise ratio to the lidar parameters and the parameters that determine the external conditions of such measurement. These equations form the foundation for a method of determining the lidar parameters and the requirements acting as the input data for a lidar development. It demonstrates that the space lidar altimeters are rationally associated with the term of the “energy space resolution” as the minimum size of the area of the terrain under resolution under the established range measurement error. The calculations carried out with the said method made it possible to assess the precision parameters of the currently used ATLAS space lidar. According to our data, a lidar is capable of providing the range measurement precision of several centimetres, provided that the objects are located within the area of several tens of cm2. The collected results bring the conclusion of the convergence of the results of the lidar precision calculation, carried out with the developed method and using the data published by NASA.