In the sea areas with heavy traffic, there is a great danger of collision or grounding. In order to improvemaritime safety at the gulf of Gdańsk in the middle of 90s, a vessel traffic services was installed. The VTSsystem operators can provide navigational assistance, if the parameters of the ships movement endanger thesafety of navigation. For proper functioning of the system there is a network of coastal radars stations whosesignal is used to create a radar picture of the navigational situation. In the vts determination of the ship position based on radar observations may lead to large errors. The IMO organization recommends to reject and repeat measurements containing large errors. For a moving ship perform a re-measurement in the same position is not possible. This paper presents possibility of compensation the coordinates of the vessel position based on radar observations using the of M-estimation methods