Ray (Autonomous Unmanned Vehicle (AUV) Workbench Documentation)

java.lang.Object
- mil.navy.nps.rra.Ray

public class Ray
extends Object

Ray implements the Recursive Ray Acoustics (rra) Algorithm derived by Professor Lawrence Ziomek to rapidly calculate a sound ray's 3D path through water, taking into account piecewise-local SSP, Surface and Bottom conditions.

Any wave front can be decomposed into a set of plane waves with the plane waves travelling in the direction of the normal to the wave front. The normal for each plane wave is defined by the normal to the wave front at the point where the front and the plane wave touch. The rra algorithm uses a difference-equation formulation of the ray theory solution to the linear acoustic wave equation. This provides a computationally rapid and theoretically general approach to simulate one ray on the surface of a wavefront as it propagates through the ocean. This makes rra an excellent choice to simulate underwater sonar under a very wide range of underwater environments.

Version:

$Revision: 1.7 $

Author:

LT Timothy M. Holliday USN

Contact: Don Brutzman (web.nps.navy.mil/~brutzman) brutzman@nps.navy.mil

Source Code:

~vrtp/mil/navy/nps/rra/Ray.java

http://web.nps.navy.mil/~brutzman/vrtp/mil/navy/nps/rra/Ray.java

History:

1 Nov 97 Timothy M. Holliday New
17 Mar 98 Timothy M. Holliday Added HTML comment convention
12 Apr 98 Timothy M. Holliday Parameterless Constructors
14 Apr 98 Timothy M. Holliday Simplified VRML Routines
10 Oct 98 Don Brutzman Javadoc updates for jdk1.2b4
25 April 99 Don Brutzman Javadoc updates for jdk1.2.1

Reference:

Holliday, Timothy, Real-Time 3D Sonar Modeling and Visualization, Master's Thesis, Naval Postgraduate School, Monterey California, June 1998. Available at vrtp/rra/HollidayRRAthesis.pdf. and web.nps.navy.mil/~brutzman/vrtp/rra/HollidayRRAthesis.pdf. Slideset available in Powerpoint and Acrobat .pdf formats.

See Also:

Beam, Lobe

Constructor Summary

Constructors
Constructor and Description

Ray()
Constructs a fixed size structure to trace a ray of acoustic energy through the ocean.

Constructors
Constructor and Description
`Ray()` Constructs a fixed size structure to trace a ray of acoustic energy through the ocean.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`double`	`getAbsorption()` Returns the current total relaxation absorbtion in dB.
`static boolean`	`getAppendLineFeed()` This is a static method that returns the current line appendage.
`double`	`getAzimuth()` Returns the azimuthal angle.
`Bottom`	`getBottom()` Returns the handle to the bottom object.
`int`	`getCount()` Returns the current number of points stored for the ray.
`double`	`getDeltaTime()` This method is returns the time step of the ray.
`int`	`getDuration()` This returns the ping duration.
`double`	`getElevation()` Returns the elevation angle.
`Vec3d`	`getNormal()` Returns the normal vector to the wavefront.
`Vec3d`	`getPosition()` Gets the position of the ray.
`double`	`getPositionX()` Returns the x-component of the position of the wavefront
`double`	`getPositionY()` Returns the y-component of the position of the wavefront
`double`	`getPositionZ()` Returns the z-component of the position of the wavefront.
`double`	`getReflectionPhase()` Returns the phase change of the wavefront
`SSP`	`getSsp()` Returns the handle to the sound speed profile object.
`Surface`	`getSurface()` Returns the handle to the surface object.
`double`	`getTime()` Returns the current simulation time.
`double`	`getTime(int index)` Returns a saved simulation time.
`Vec3d`	`getTrailingPosition()` Returns the position of the trailing edge of the wavefront.
`boolean`	`hasIntersectedBottom(Vec3d Pos)` Evaluates the 3-position of vectors whether they meet in interpolation current depth criteria.
`String`	`normalizedTime(int N, double endtime)` Returns the requested normalized time as a string.
`String`	`position(int N)` Returns the requested position as a String.
`void`	`Propagate(double timeStep)` This method causes the ray to propagate one timestep into the future.
`void`	`recordPoint()` This method forces a recording of the current ray position.
`boolean`	`reflected()` Returns whether or not the ray has been reflected in the most recent time step.
`void`	`reset()` This method resets all of the ray parameters after instantiation has occurred since reuse is more time efficient than garbage collection and reallocation.
`static void`	`setAppendLineFeed(boolean pAppendLineFeed)` This is a static method used to indicate whether a line feed is desired at the end of every line.
`void`	`setAzimuth(double phi)` Sets the azimuthal angle, which is the angle from the x-axis to the z-axis rotating about the y-axis.
`void`	`setBottom(Bottom pBottom)` Sets the handle to the bottom object.
`void`	`setDeltaTime(double deltaTime)` This method is used to change the time step of the ray after instanciation.
`void`	`setDuration(int duration)` This method sets the ping duration.
`void`	`setElevation(double beta)` Sets the elevation angle, which is the angle from the y-axis to the x-axis rotating about the z-axis.
`void`	`setPosition(double x, double y, double z)` Sets the position of the ray.
`void`	`setSsp(SSP pSsp)` Sets the handle to the sound speed profile object.
`void`	`setSurface(Surface pSurface)` Sets the handle to the surface object.
`double`	`totalCurvature()` Returns the total curvature of the ray path since the last recorded point.
`String`	`trailingPosition(int N)` Returns the requested trailing edge of the ray as a String.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Ray
```
public Ray()
```
    Constructs a fixed size structure to trace a ray of acoustic energy through the ocean. Use accessor methods to set initial values of member variables.
- Method Detail
  - reset
```
public void reset()
```
    This method resets all of the ray parameters after instantiation has occurred since reuse is more time efficient than garbage collection and reallocation.
  - getNormal
```
public Vec3d getNormal()
```
    Returns the normal vector to the wavefront.
    
    Returns:
    
    The normal vector to the wavefront.
  - setAzimuth
```
public void setAzimuth(double phi)
```
    Sets the azimuthal angle, which is the angle from the x-axis to the z-axis rotating about the y-axis.
    
    Parameters:
    
    phi - The azimuthal angle.
  - getAzimuth
```
public double getAzimuth()
```
    Returns the azimuthal angle.
    
    Returns:
    
    The azimuthal angle.
  - setElevation
```
public void setElevation(double beta)
```
    Sets the elevation angle, which is the angle from the y-axis to the x-axis rotating about the z-axis.
    
    Parameters:
    
    beta - The elevation angle.
  - getElevation
```
public double getElevation()
```
    Returns the elevation angle.
    
    Returns:
    
    The elevation angle.
  - setPosition
```
public void setPosition(double x,
                        double y,
                        double z)
```
    Sets the position of the ray.
    
    Parameters:
    
    x - The oordinate x.
    
    y - The coordinate y.
    
    z - The coordinate z.
  - getPosition
```
public Vec3d getPosition()
```
    Gets the position of the ray.
    
    Returns:
    
    The 3-element vectors.
  - setDeltaTime
```
public void setDeltaTime(double deltaTime)
```
    This method is used to change the time step of the ray after instanciation.
    
    Parameters:
    
    deltaTime - The time step of the ray.
  - getDeltaTime
```
public double getDeltaTime()
```
    This method is returns the time step of the ray.
    
    Returns:
    
    The time step of the ray.
  - setDuration
```
public void setDuration(int duration)
```
    This method sets the ping duration. Duration is currently 1 or 2. The integer refers to the number of deltaTime increments.
    
    Parameters:
    
    duration - The ping duration.
  - getDuration
```
public int getDuration()
```
    This returns the ping duration. Duration is currently 1 or 2. The integer refers to the number of deltaTime increments.
    
    Returns:
    
    the ping duration.
  - setBottom
```
public void setBottom(Bottom pBottom)
```
    Sets the handle to the bottom object.
    
    Parameters:
    
    pBottom - the Bottom object.
  - getBottom
```
public Bottom getBottom()
```
    Returns the handle to the bottom object.
    
    Returns:
    
    The Bottom object.
  - setSurface
```
public void setSurface(Surface pSurface)
```
    Sets the handle to the surface object.
    
    Parameters:
    
    pSurface - the Surface object.
  - getSurface
```
public Surface getSurface()
```
    Returns the handle to the surface object.
    
    Returns:
    
    The Surface object.
  - setSsp
```
public void setSsp(SSP pSsp)
```
    Sets the handle to the sound speed profile object.
    
    Parameters:
    
    pSsp - The SSP(Sound Speed Profile) object.
  - getSsp
```
public SSP getSsp()
```
    Returns the handle to the sound speed profile object.
    
    Returns:
    
    The SSP(Sound Speed Profile) object.
  - getReflectionPhase
```
public double getReflectionPhase()
```
    Returns the phase change of the wavefront
    
    Returns:
    
    The phase change of the wavefront.
  - getPositionX
```
public double getPositionX()
```
    Returns the x-component of the position of the wavefront
    
    Returns:
    
    The x-component of the position of the wavefront.
  - getPositionY
```
public double getPositionY()
```
    Returns the y-component of the position of the wavefront
    
    Returns:
    
    The y-component of the position of the wavefront.
  - getPositionZ
```
public double getPositionZ()
```
    Returns the z-component of the position of the wavefront.
    
    Returns:
    
    The z-component of the position of the wavefront.
  - getTrailingPosition
```
public Vec3d getTrailingPosition()
```
    Returns the position of the trailing edge of the wavefront.
    
    Returns:
    
    the position of the trailing edge of the wavefront.
  - getTime
```
public double getTime()
```
    Returns the current simulation time.
    
    Returns:
    
    The current simulation time.
  - getTime
```
public double getTime(int index)
```
    Returns a saved simulation time.
    
    Parameters:
    
    index - The array of index.
    
    Returns:
    
    The simulation time.
  - Propagate
```
public void Propagate(double timeStep)
```
    This method causes the ray to propagate one timestep into the future.
    
    Parameters:
    
    timeStep - The time step of the ray.
  - getCount
```
public int getCount()
```
    Returns the current number of points stored for the ray.
    
    Returns:
    
    The current number of points stored for the ray.
  - getAbsorption
```
public double getAbsorption()
```
    Returns the current total relaxation absorbtion in dB.
    
    Returns:
    
    The current total relaxation absorbtion in dB.
  - reflected
```
public boolean reflected()
```
    Returns whether or not the ray has been reflected in the most recent time step.
    
    Returns:
    
    'true' if ray has been reflected; 'false' otherwise.
  - recordPoint
```
public void recordPoint()
```
    This method forces a recording of the current ray position. It also forces the total curvature of the ray since the last recorded point to 0.0.
  - totalCurvature
```
public double totalCurvature()
```
    Returns the total curvature of the ray path since the last recorded point. The curvature of a small segment of curve can be approximated by the curvature of a circle which is the change in angular position around the circle divided by the pathlength change. K = deltaTheta/deltaPathLength. Thus total curvature is the sum of the curvatures of the small segments along a ray trajectory.
    
    Returns:
    
    The sum of the curvatures of the small segments along a ray trajectory.
  - position
```
public String position(int N)
```
    Returns the requested position as a String.
    
    Parameters:
    
    N - The index for array.
    
    Returns:
    
    String of the requested position.
  - trailingPosition
```
public String trailingPosition(int N)
```
    Returns the requested trailing edge of the ray as a String.
    
    Parameters:
    
    N - The index for array.
    
    Returns:
    
    String of the requested trailing edge of the ray.
  - normalizedTime
```
public String normalizedTime(int N,
                             double endtime)
```
    Returns the requested normalized time as a string.
    
    Parameters:
    
    N - The index for array.
    
    endtime - The time of after the time step.
    
    Returns:
    
    String of the normalized time.
  - setAppendLineFeed
```
public static void setAppendLineFeed(boolean pAppendLineFeed)
```
    This is a static method used to indicate whether a line feed is desired at the end of every line.
    
    Parameters:
    
    pAppendLineFeed - 'true' indicates a linefeed is desired and 'false' indicates that a space is desired"
  - getAppendLineFeed
```
public static boolean getAppendLineFeed()
```
    This is a static method that returns the current line appendage.
    
    Returns:
    
    'true' indicates a linefeed is desired and 'false' indicates that a space s desired"
  - hasIntersectedBottom
```
public boolean hasIntersectedBottom(Vec3d Pos)
```
    Evaluates the 3-position of vectors whether they meet in interpolation current depth criteria.
    
    Parameters:
    
    Pos - The 3-position of vectors.
    
    Returns:
    
    'true' if vectors are in criteria; 'false' otherwise.

1 Nov 97	Timothy M. Holliday	New
17 Mar 98	Timothy M. Holliday	Added HTML comment convention
12 Apr 98	Timothy M. Holliday	Parameterless Constructors
14 Apr 98	Timothy M. Holliday	Simplified VRML Routines
10 Oct 98	Don Brutzman	Javadoc updates for jdk1.2b4
25 April 99	Don Brutzman	Javadoc updates for jdk1.2.1

Class Ray

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Ray

Method Detail

reset

getNormal

setAzimuth

getAzimuth

setElevation

getElevation

setPosition

getPosition

setDeltaTime

getDeltaTime

setDuration

getDuration

setBottom

getBottom

setSurface

getSurface

setSsp

getSsp

getReflectionPhase

getPositionX

getPositionY

getPositionZ

getTrailingPosition

getTime

getTime

Propagate

getCount

getAbsorption

reflected

recordPoint

totalCurvature

position

trailingPosition

normalizedTime

setAppendLineFeed

getAppendLineFeed

hasIntersectedBottom