• Advances in aircraft and spacecraft science
• /
• v.7 no.1
• /
• pp.1-17
• /
• 2020

In this paper, a new model-based Fault Detection and Diagnosis (FDD) method for an agile supersonic flight vehicle is presented. A nonlinear model, controlled by a classical closed loop controller and proportional navigation guidance in interception scenario, describes the behavior of the vehicle. The proposed FDD method employs the Inertial Navigation System (INS) data and nonlinear dynamic model of the vehicle to inform fins damage to the controller before leading to an undesired performance or mission failure. Broken, burnt, unactuated or not opened control surfaces cause a drastic change in aerodynamic coefficients and consequently in the dynamic model. Therefore, in addition to the changes in the control forces and moments, system dynamics will change too, leading to the failure detection process being encountered with difficulty. To this purpose, an equivalent aerodynamic model is proposed to express the dynamics of the vehicle, and the health of each fin is monitored by the value of a parameter which is estimated using an adaptive robust filter. The proposed method detects and isolates fins damages in a few seconds with good accuracy.

• Journal of Advanced Navigation Technology
• /
• v.2 no.2
• /
• pp.84-99
• /
• 1998

As a part of closed-loop guidance law studies for anti-ballistic missile defense, a mid-course guidance law is proposed to engage the target with the predetermined attitude for increased terminal effectiveness. The proposed guidance law is based on the predicted target position calculated from a simplified solution of target motion and the estimates of an extended Kalman filter utilizing noisy nonlinear radar measurements. Extension of the proposed mid-course guidance to 3 dimensional engagements are also studied. Performance of the proposed mid-course guidance law together with a terminal guidance law in the form of conventional proportional navigation guidance is evaluated by a series of simulation studies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1996.04a
• /
• pp.77-92
• /
• 1996

When an automatic course-keeping is concerned as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit (or telemotor unit) steering gear magnetic or gyro compass and ship dynamics. The consideration of irregular disturbances to ship dyanmics and a few non-linear mechanisms involved in the system inevitably or artificially are known to be very important in properly evaluating or analyzing the automatic steering system. In the present study the mathematical model of each element of an automatic steering system is derived which takes account of a fex non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. The calculation method of imposing irregular disturbances to ship dynamics is proposed where irregular disturbances implying irregular wave and the fluctuating component of wind. For he evaluation of automatic steering system of ships in the open seas an important term "performance index" is introduced from the viewpoint of energy saving which derived from the concept of energy loss on ship propulsion. Finally the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of linear and/or non-linear control constants of autopilot on propulsive energy loss are investigated to validate and clarify the present smulation technique.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.06a
• /
• pp.15-16
• /
• 2014

As trade cross the world is increasing these days, safe and effective management of harbour system is becoming important issue. With this background, the development of automatic time-domain simulation programme for ship berthing operation has been being peformed and PD (Proportional Derivative) controller has been used to control the speed and the heading angle of ships. This paper provides feasibility study for developing the time-domain simulation programme for berthing operation of ships with analysing advantages and drawbacks of the two different mathematical models, one is for low advance speed of ships by Kose (1984) and the other is MMG model for normal advance speed, through the simulations with various initial heading angles and positions of the ship.

• Journal of the Korean Institute of Navigation
• /
• v.12 no.1
• /
• pp.71-84
• /
• 1988

For traffic proceeding in random directions on a plane surface the frequency of collision, if no avoiding action in taken ,is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the ship, Avoiding is normally taken and the rte of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collisionavoidance rules, the competence of personnel or watchkeeping attitude, the maneuverability of the ship and the efficiency of radar and other equipments. From the viewpoint of watchkeeper who is responsible for maneuvering, watchkeeping attitude such as lookout and action to avoid collision is the most controllable factor among those mentioned above. In practice, according to the investigation of the institution of marine courts, about 50% co collisions occurred is caused by disorbedience to steering and sailing rules of international regulations for preventing collision at sea including lookout. So we classify the process of collisions with first sight of another ship , assessment of risk of collisions and action to avoid collisions and make a factural survey about lookout and action to avoid collisions from the point on "time" and " distance", namely relationship among ship's size, speed, first sight time of another ship, action to avoid collisions ,and distance from sight of another ship to collision occurred. According to the results of the actual survey , we come to conclude that most of collisions occurred are due to improper lookout and ineffective action to avoid collision which means time lag from first sight of another ship to time of action taken to avoid collision is relatively long. is relatively long.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.288-293
• /
• 2010

This paper presents to calculate the lethality of missile for the simulation test program and to verify the simulation results. In order to calculate a reliable lethality we need may data and experiments of fuse and warhead, but in reality it is hard to perform a task. Therefore, this paper obtained from the reference paper to analyze the lethality data for the calculation of the lethality. We form the 6 DOF simulation model using the MATLAB/SIMULINK. And formed the autopilot algorithm using the vertical and horizontal acceleration feedback and PNG (Proportional Navigation Guidance) command be used to the guidance algorithm. Finally, we evaluate the results about three cases, front launch, side launch and rear launch to simulate the simulation program, and the target is designed to have a constant speed and direction.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.1
• /
• pp.20-28
• /
• 2014

In this paper, based on the characteristics of proportional navigation, a composite guidance law is proposed for impact angle control of passive homing missiles maintaining the lock-on condition of the seeker. The proposed law is composed of two guidance commands: the first command is to keep the look angle constant after converging to the specific look angle of the seeker, and the second is to impact the target with terminal angle constraint and is implemented after satisfying the specific line of sight(LOS) angle. Because the proposed law considers the seeker's filed-of-view(FOV) and acceleration limits simultaneously and requires neither time-to-go estimation nor relative range information, it can be easily applied to passive homing missiles. The performance and characteristics of the proposed law are investigated through nonlinear simulations with various engagement conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.06a
• /
• pp.299-300
• /
• 2013

In this study, the time-domain simulations have been performed for analysing the ship behaviour during berthing process with comparing the two different mathematical models for low and normal advance speed of a ship and the results have been presented. For the first step of programming, the traditional PD (Proportional Derivative) controller has been used for the control of speed and rudder and a tanker ship has been used as a simulation model. This study provides comparative results on the time-domain simulation of berthing operation of a ship for developing an effective simulation programme.

• Journal of Navigation and Port Research
• /
• v.46 no.6
• /
• pp.554-561
• /
• 2022

Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.7
• /
• pp.69-75
• /
• 2004

An avoidance/guidance problem of an aircraft against moving obstacle is considered in two dimensional space. The aircraft is modelled as a point mass flying with constant speed. The lateral acceleration is assumed the control input. Artificial potential functions are applied to the terminal point and moving obstacles in order that repulsive forces and an attractive force are produced by the obstacles and the terminal point respectively. A real time guidance/avoidance law is proposed by using the potential forces and relative velocity. The guidance law for a logarithm potential function results the well-known proportional navigation law. The avoidance control command is inverse proportional to the time-to-go to the obstacle and turns the aircraft toward the negative direction of the line-of-sight change. The performance of the proposed guidance/avoidance law is verified with simulations.