Order-variant sliding trend analysis and its application

In this papcr, we make use of the orthogonal transformation method to transform the coefficient matrix of trcnd surface analysis to a diagonal matrix so as to avoid solving ill-conditioned system of cquations and improve the precision of solution, Meanwhile, the normal equations are transformed to a first-ordcr system of cquations which is very casy to solve,thcrefore, the solving process is sped up. Furthcr, the order-fixed trend surface analysis which is responsible for false anomaly is replaeed by sliding window and order-variant trend surface analysis. As a result, the application of the method in recognizing weak anomalies of high accuracy gravity survey and determining the accurate position of buried hill in oil-bearing sedimcntary basin has brought forth sat isfactory results.