State estimation method and system under heading constraint

The invention provides a state estimation method and system under heading constraint. The method comprises the following steps: under the condition that heading is known, augmenting a state vector anda covariance matrix by utilizing nodal increment of a constraint straight line, and augmenting an original state equation; calculating an initial value; constructing pseudo measurement based on a position constraint relation and a corresponding speed constraint relation; augmenting a measurement equation by utilizing the pseudo measurement; based on the augmented state equation and the augmentedmeasurement equation, and initial values of the state vector and the covariance matrix, carrying out extended Kalman filtering to obtain a filtering result of a target position. By adopting the stateestimation method and system under the heading constraint, the state estimation problem under incomplete constraint conditions is solved; prior known information is sufficiently utilized and wastes ofthe information are avoided