Signal source number estimation method based on adaptive diagonal loading

The invention relates to an information source number estimation method based on adaptive diagonal loading. The method comprises the following steps: S1, calculating a sample sampling covariance matrix and a characteristic value thereof based on array antenna output data; s2, adaptively calculating a diagonal loading amount by using an antenna number, a sample number and a characteristic value under v assumed information sources; s3, calculating linear expansion and contraction coefficients under k (< = v) assumed information sources by using the loaded characteristic values; and S4, constructing a second-order difference operator based on a linear expansion coefficient, and searching a maximum v value which enables the difference operator to be greater than zero to complete information source number estimation. Compared with a current mainstream signal source number method, the method provided by the invention not only is efficient in calculation and good in noise robustness, but also has better applicabilit