ned2aer

Transform local north-east-down coordinates to local spherical

Description

example

[az,elev,slantRange] = ned2aer(xNorth,yEast,zDown) transforms the local north-east-down (NED) Cartesian coordinates specified by xNorth, yEast, and zDown to the local azimuth-elevation-range (AER) spherical coordinates specified by az, elev, and slantRange. Both coordinate systems use the same local origin. Each input argument must match the others in size or be scalar.

[___] = ned2aer(___,angleUnit) specifies the units for azimuth and elevation. Specify angleUnit as 'degrees' (the default) or 'radians'.

Examples

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Find the AER coordinates of a landmark with respect to an aircraft, using the NED coordinates of the landmark with respect to the same aircraft.

First, specify the NED coordinates of the landmark. For this example, specify the coordinate values in kilometers.

xNorth = -9.1013;
yEast = 4.1617;
zDown = 4.2812;

Then, calculate the AER coordinates of the landmark. The azimuth and elevation are specified in degrees. The units for the slant range match the units specified by the NED coordinates. Thus, the slant range is specified in kilometers.

[az,elev,slantRange] = ned2aer(xNorth,yEast,zDown)
az = 155.4271
elev = -23.1609
slantRange = 10.8849

Reverse the transformation using the aer2ned function.

[xNorth,yEast,zDown] = aer2ned(az,elev,slantRange)
xNorth = -9.1013
yEast = 4.1617
zDown = 4.2812

Input Arguments

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NED x-coordinates of one or more points in the local NED system, specified as a scalar, vector, matrix, or N-D array.

Data Types: single | double

NED y-coordinates of one or more points in the local NED system, specified as a scalar, vector, matrix, or N-D array.

Data Types: single | double

NED z-coordinates of one or more points in the local NED system, specified as a scalar, vector, matrix, or N-D array.

Data Types: single | double

Units of angles, specified as 'degrees' (the default) or 'radians'.

Data Types: char | string

Output Arguments

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Azimuth angles of one or more points in the local AER system, returned as a scalar, vector, matrix, or N-D array. Azimuths are measured clockwise from north. Values are specified in degrees within the half-open interval [0 360). To use values in radians, specify the angleUnit argument as 'radians'.

Elevation angles of one or more points in the local AER system, returned as a scalar, vector, matrix, or N-D array. Elevations are calculated with respect to the xNorth-yEast plane that contains the local origin. If the local origin is on the surface of the spheroid, then the xNorth-yEast plane is tangent to the spheroid.

Values are specified in degrees within the closed interval [-90 90]. Positive elevations correspond to negative zDown values, and negative elevations correspond to positive zDown values. An elevation of 0 indicates that the point lies in the xNorth-yEast plane. To use values in radians, specify the angleUnit argument as 'radians'.

Distances from the local origin, returned as a scalar, vector, matrix, or N-D array. Each distance is calculated along a straight, 3-D, Cartesian line. Values are returned in the units specified by xNorth, yEast, and zDown.

Introduced in R2012b