New relative positioning method for ship formation

The invention discloses a new relative positioning method for ship formation. The relative positioning method comprises the steps that a ship formation relative positioning system based on a ship-carried data chain, ship-carried inertial navigation and a relative positioning computer is established, the ship formation relative positioning system is installed on each ship of the ship formation, information interaction contents between the adjacent ships of the ship formation during relative positioning are determined, data of the ship-carried inertial navigation is transmitted to the ship-carried data chain, the ship-carried data chain makes use of radio range finding to carry out mutual distance measurement between every two ships in the ship formation, also makes use of radio communications to notify the inertial navigation data and distance measurement information in real time and transmits the inertial navigation data and the distance measurement information to the relative positioning computer, a distance calculation difference obtained through calculation of the distance measurement information and the inertial navigation data of the ships is used in quantity measurement, a position error of the inertial navigation of each ship is taken as a to-be-estimated amount, and a mathematical model of the relative positioning method of the ship formation is established. The new relative positioning method disclosed by the invention can increase position accuracy of the ship inertial navigation by over two times.