“…In practice, filtering problems often have certain inherent and known constraints in the physical dynamic systems [1], for example, target tracking [2,3], robotics [4], multisensor data fusion [5,6], vision-based systems [7], econometric modeling [8], biomedical systems [9] and others [10,11]. For equality-constrained state estimation, numerous approaches have been developed, for example, the model reduction method [5,6,12], the pseudo measurement method [13][14][15][16][17][18], the estimate projection method [19,20], the system projection method [21], the gain projection method [22], and some other methods [11,23].…”