Coordination of a group of robots in an in-line formation by using a hybrid posture estimation strategy that combines visual perception and optical (laser) pointers is addressed in this research. The posture estimation system functions by analysing the changes in laser beam points that are projected from follower robot onto the leader robot during formation to evaluate the orientation angle of leader robot and the linear distance between the robots. The posture estimation system is designed to estimate the posture of the leader robot and to observe the in-line formation of the robots. The proposed system adjusts the trajectory of follower robot to maintain the desired linear separation and orientation angle as well as to sustain the in-line formation. This is achieved by regulating the translational and rotational velocity of the follower robot to bring any deviation from the desired posture asymptotically to zero.