Downward continuation recursive cosine transform method of plane geomagnetic anomaly field

Abstract

The present invention discloses a downward continuation recursive cosine transform method of a plane geomagnetic anomaly field, and belongs to the field of geomagnetic field data processing. The concrete steps are as follows: preprocessing measurement data of the plane geomagnetic anomaly field; gridding the measurement data of the plane geomagnetic anomaly field; calculating the cosine transformspectrum of the plane geomagnetic anomaly field by means of the recursive cosine transform; setting a small amount epsilon according to the precision requirement of downward continuation, and selecting the value of the damping factor alpha; directly calculating the spectrum of the continuation plane geomagnetic anomaly field through the compensation factors of the cosine transform spectrum on theobservation side and the downward continuation of the plane geomagnetic anomaly field; and carrying out one-dimensional recursive inverse cosine transform in row and in column on the spectrum to obtain a continuation value. According to the method disclosed by the present invention, large-distance downward continuation of the geomagnetic anomaly field can be stably carried out only through one-step spectral transformation and inverse transformation, so that the calculation amount of the downward continuation algorithm is reduced, the recursive algorithm has a small amount of calculation, and the precision of large-distance downward continuation of one-step spectral compensation of the plane geomagnetic anomaly field is improved.

Description

technical field [0001] The invention belongs to the field of geomagnetic potential field data processing, and in particular relates to a downward extension recursive cosine transform method of a plane geomagnetic anomaly field. Background technique [0002] In potential field data processing, the downward continuation of geomagnetic anomalies is of great significance for geological surveys, UXO detection, and geomagnetic-assisted navigation. Aeromagnetic anomaly measurement is indispensable in areas with harsh measurement conditions such as sea surface, surface and ultra-low altitude. Using aeromagnetic data to carry out downward continuation at different heights can make up for the lack of magnetic field data in areas with harsh conditions. Large-distance downward continuation can attribute aeromagnetic data and ship survey geomagnetic anomaly data to the underwater, providing support for underwater navigation. The geomagnetically assisted navigation of the sensor provides...

AI Technical Summary

Problems solved by technology

Recursive cosine transform and inverse transform can also be adapted to data sequences of any length, while fast Fourier transform and inverse transform usually require the length of the data sequence to be the integer power of the base number, and zero padding will increase the calculation amount of the algorithm

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