radialspeed

Relative radial speed

Syntax

Rspeed = radialspeed(Pos,V)

Rspeed = radialspeed(Pos,V,RefPos)

Rspeed = radialspeed(Pos,V,RefPos,RefV)

Description

Rspeed = radialspeed(Pos,V) returns the radial speed of the given platforms relative to a reference platform. The platforms have positions Pos and velocities V. The reference platform is stationary and is located at the origin.

Rspeed = radialspeed(Pos,V,RefPos) specifies the position of the reference platform.

Rspeed = radialspeed(Pos,V,RefPos,RefV) specifies the velocity of the reference platform.

Examples

Radial Speed of Target Relative to Stationary Platform

Calculate the radial speed of a target relative to a stationary platform. Assume the target is located at (20,20,0) meters in Cartesian coordinates and is moving with velocity (10,10,0) meters per second. The reference platform is located at (1,1,0).

rspeed = radialspeed([20; 20; 0],[10; 10; 0],[1; 1; 0])

rspeed = 
-14.1421

Negative radial speed indicates that the target is receding from the platform.

Input Arguments

Pos — Positions of platforms

matrix

Positions of platforms, specified as a 3-by-N matrix. Each column specifies a position in the form [x; y; z], in meters.

Example: [20; 20; 0]

Data Types: double

V — Velocities of platforms

matrix

Velocities of platforms, specified as a 3-by-N matrix. Each column specifies a velocity in the form [x; y; z], in meters per second.

Example: [10; 10; 0]

Data Types: double

RefPos — Position of reference platform

[0; 0; 0] (default) | vector

Position of reference platform, specified as a 3-by-1 vector. The vector has the form [x; y; z], in meters.

Example: [1; 1; 0]

Data Types: double

RefV — Velocity of reference platform

[0; 0; 0] (default) | vector

Velocity of reference platform, specified as a 3-by-1 vector. The vector has the form [x; y; z], in meters per second.

Example: [1; -1; 0]

Data Types: double

Output Arguments

Rspeed — Radial speed

vector

Radial speed in meters per second, returned as an N-by-1 vector. Each number in the vector represents the radial speed of the corresponding platform. Positive numbers indicate that the platform is approaching the reference platform. Negative numbers indicate that the platform is moving away from the reference platform.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

Does not support variable-size inputs.

Version History

Introduced in R2011a