# ned2aer

Transform local north-east-down coordinates to local spherical

## Syntax

``````[az,elev,slantRange] = ned2aer(xNorth,yEast,zDown)``````
``[___] = ned2aer(___,angleUnit)``

## 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

collapse all

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

collapse all

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`

Angle units, specified as `'degrees'` (the default) or `'radians'`.

## Output Arguments

collapse all

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`.

## Version History

Introduced in R2012b

expand all