Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on Trajectory Measurement Method of Underwater High-speed Attack Weapon in the Geodetic
Coordinate System
Zhigang Wang1,Zhongya Xia1,Yingyuan Tian23
1.Yichang Testing Technique Research Institute.
Yichang, Hubei, China
2. School of naval, Huazhong university of science and technology.
Wuhan, Hubei, China
3.Qingdao Innovation and Development Center of Harbin Engineering University.
Qingdao, Shandong, China

the process of underwater high-speed attack weapon and surface target
trajectory rendezvous testing, since the trajectories of both are notmeasured under the same coordinate system, underwater high-speed
attack weapon ballistic data are obtained under the navigation coordinatesystem, which is a customized coordinate system based on thenavigational body, while the surface target trajectory is obtained under
the geodetic coordinate system. In order to evaluate the weapon andequipment performance, optimize the ballistic control algorithm, anddetermine the strike point error, it is necessary to accurately measure theballistic data of the underwater weapon in the geodetic coordinate system.
In this paper, a ballistic measurement method for underwater high-speed
attack weapons in geodetic coordinate system is presented.

ABSTRACT
When assessing the hitting accuracy of underwater attack weapons
against the surface target, we need to convert different coordinate
systems to a unified coordinate system. Typically, surface target trackuses the geodetic coordinate system and underwater weapon trajectoryuses a navigation coordinate system. Therefore, trajectory data in thenavigation coordinate system needs to be converted to the geodetic
coordinate system. Using an inertial measurement unit can only get thetrajectory data in the navigation coordinate system. Because of the
Doppler effect, underwater acoustic reverberation, and measurement
period, using cooperative acoustic beacon or baseline positioning
method makes a great error in underwater high-speed attack weapon
trajectory measurement. In this paper, a method combining baseline
positioning with an inertial measurement unit is proposed to solve theproblem of trajectory measurement in the geodetic coordinate system ofunderwater high-speed weapons. The system composition, working
principle, and test results are introduced, and the measurement errors areanalyzed.

TRAJECTORY MEASUREMENT METHODS
Acoustic technology is one of the viable methods to measure thetrajectory and attitude of underwater navigational bodies. In addition,
the autonomous measurement that do not depend on external conditions,such as inertial measurements, is a viable technical approach toachieving underwater trajectories and attitudes. (Ji,2014).

KEY WORDS: high-speed attack weapon; trajectorymeasurement; navigation coordinate system; geodetic coordinatesystem.
INTRODUCTION
Testing is an essential tool in the process of product development, testing,and production. The trajectory parameters that can be obtained fromunderwater trajectory measurement include attitude angle, angular rate,
velocity, displacement, ballistic inclination, ballistic deflection, tilt angle,
angle of attack, sideslip angle, etc. According to the data measured by
the ballistic measurement system, the ballistic trajectory, ballistic
dispersion, action characteristics, and performance of the weapon can bedetermined as an important basis for parameter optimization and design
improvement during product development, and the underwater ballistic
testing process is extensive, difficult, and costly (Zhang, et al. 2018). In1030

The acoustic field, as the physical field with the best propagation effectin water, can achieve effective propagation in a large range. Therefore,
underwater weapons ranges widely use acoustic positioning technology
as the ballistic external measurement system to achieve high-precision
real-time ballistic measurements of fast-moving targets in the water, totest the performance of weapons and equipment (Li,2011). The active
external measurement system achieves tracking and measurement of awide range of targets in water by adding acoustic devices to the target.
The active measurement system consists of two parts: a transponder basearray fixed on the seafloor and an acoustic device mounted on themeasured target, mainly using the synchronous positioning method andthe asynchronous positioning method (Tian,2007). The array isdetermined by calibrating the absolute position of the seabed transponder
on the geodetic coordinate system before the measurement test to ensurethat the system solves the real-time geodetic coordinate position of the