Time-varying correction method and system for gravity reference map based on time-varying gravity anomaly

Abstract

The invention discloses a gravity-anomaly-time-varying-based time-varying correction method and system for a gravity reference map. Calculation is carried out based on GRACE satellite data to obtain gravity data and then calculation is carried out based on the gravity data to obtain a monthly gravity field model; a certain monthly gravity field model is selected as a background gravity field modeland a difference between the monthly gravity field model and the background gravity field model is calculated to obtain a gravity anomaly change formula under the background gravity field; the formula is filtered to eliminate the influences of the north-south strip errors; classification abstract summation is carried out on time-varying influencing factors of the gravity field based on an influence principle to obtain a gravity anomaly fitting formula, and a gravity anomaly long-term changing rate is obtained by combining the filtered gravity anomaly change formula so as to realize predictionof the gravity anomaly change; and then a gravity anomaly time-varying formula at a current time is determined based on the gravity anomaly long-term changing rate and thus time-varying correction iscarried out on original data used for preparing a gravity reference map to obtain a time-varying corrected gravity reference map. Therefore, the mismatch rate of the gravity reference map is reduced.

Description

technical field [0001] The invention belongs to the field of control theory, and mainly aims at the problem that the navigation matching accuracy of the existing gravity reference map decreases with time, and proposes a time-varying correction method and system for the gravity reference map based on the time-varying gravity anomaly. Background technique [0002] It is intuitively believed that, except for the influence of earthquakes and other factors, the earth's gravity field is static and does not change with time. This is also the key and basic starting point for the gravity value to be used as a passive auxiliary navigation matching element. [0003] With the progress of gravity measurement technology and the in-depth study of the earth's gravity field, the phenomenon that the change of the earth's material distribution caused the gravity field to change with time was discovered. At the same time, with the successive launches of gravity satellites, the study of time-var...

AI Technical Summary

Problems solved by technology

[0004] At present, the existing technology can accurately measure gravity data on a global scale, with high accuracy, but it is not time-varying. Only through multiple measurements can it be found that gravity is changing

Then, the gravity reference map drawn by the measured gravity data is not time-varying. When navigating and the initial navigation effect is good, due to the lack of timeliness, after the gravity reference map is prepared, if it is not correct for a long time It performs time-varying correction. When the navigation matching is performed again, a large error will appear, and the positioning accuracy will be significantly reduced.

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