elevation
Local vertical elevation angle, range, and azimuth
elevation will be removed in a future release. Use geodetic2aer instead.
The reference point comes second in the geodetic2aer argument list,
and the outputs are ordered differently. The replacement pattern is:
[azimuthangle, elevationangle, slantrange] = geodetic2aer(lat2, lon2, alt2, lat1,
lon1, alt1, spheroid, ...)
Unlike elevation, geodetic2aer requires a spheroid
input, and it must be an oblateSpheroid, referenceEllipsoid, or referenceSphere object, not a 2-by-1 ellipsoid vector.
You can use the following steps to convert an ellipsoid vector,
ellipsoid, to an oblateSpheroid object,
spheroid:
spheroid = oblateSpheroid;spheroid.SemimajorAxis = ellipsoid(1);spheroid.Eccentricity = ellipsoid(2);
When elevation is called with only 6 inputs, the GRS 80 reference ellipsoid, in
meters, is used by default. To replace this usage, use
referenceEllipsoid('GRS80','meters') as the spheroid input for
geodetic2aer.
If an angleunits input is included, it must follow the
spheroid input in the call to geodetic2aer, rather
than preceding it.
You can specify the lengthunits parameter when calling
elevation, but geodetic2aer has no such input.
Instead, set the LengthUnit property of the input spheroid to the desired
value. In this case a referenceEllipsoid or
referenceSphere object must be used (not an
oblateSpheroid object).
Syntax
[elevationangle,slantrange,azimuthangle]
= ...
elevation(lat1,lon1,alt1,lat2,lon2,alt2)
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
angleunits)
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
angleunits,distanceunits)
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
angleunits,ellipsoid)
Description
[elevationangle,slantrange,azimuthangle]
= ...
computes the elevation angle, slant range, and azimuth angle of point 2 (with geodetic
coordinates
elevation(lat1,lon1,alt1,lat2,lon2,alt2)lat2, lon2, and alt2) as
viewed from point 1 (with geodetic coordinates lat1,
lon1, and alt1). The coordinates
alt1 and alt2 are ellipsoidal heights. The elevation
angle is the angle of the line of sight above the local horizontal at point 1. The slant range
is the three-dimensional Cartesian distance between point 1 and point 2. The azimuth is the
angle from north to the projection of the line of sight on the local horizontal. Angles are in
units of degrees; altitudes and distances are in meters. The figure of the earth is the
default ellipsoid (GRS 80).
Inputs can be vectors of points, or arrays of any shape, but must match in size, with the following exception: Elevation, range, and azimuth from a single point to a set of points can be computed very efficiently by providing scalar coordinate inputs for point 1 and vectors or arrays for point 2.
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
where
angleunits)angleunits specifies the units of the input and output angles. If you
omit angleunits, 'degrees' is assumed.
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
where
angleunits,distanceunits)distanceunits specifies the altitude and slant-range units. If you
omit distanceunits, 'meters' is the default. Any units
value recognized by unitsratio may be used.
[...] = elevation(lat1,lon1,alt1,lat2,lon2,alt2,...
uses
angleunits,ellipsoid)ellipsoid to specify the ellipsoid. ellipsoid is a
referenceSphere, referenceEllipsoid, or oblateSpheroid object, or a vector of the form [semimajor_axis
eccentricity]. If ellipsoid is supplied, the altitudes must be
in the same units as the semimajor axis, and the slant range will be returned in these units.
If ellipsoid is omitted, the default is a unit sphere. Distances are in
meters unless otherwise specified.
Note
The line-of-sight azimuth angles returned by elevation will generally
differ slightly from the corresponding outputs of azimuth and
distance, except for great circle azimuths on a spherical earth.
Examples
Find the elevation angle of a point 90 degrees from an observer assuming that the observer and the target are both 1000 km above the Earth.
lat1 = 0; lon1 = 0; alt1 = 1000*1000; lat2 = 0; lon2 = 90; alt2 = 1000*1000; elevang = elevation(lat1,lon1,alt1,lat2,lon2,alt2) elevang = -45
Visually check the result using the los2 line of sight function.
Construct a data grid of zeros to represent the Earth's surface. The
los2 function with no output arguments creates a figure displaying
the geometry.
Z = zeros(180,360); refvec = [1 90 -180]; los2(Z,refvec,lat1,lon1,lat2,lon2,alt1,alt1);
