reckon function query

Hi i am looking to try calculate the latitude and longitude of a point on the ground with respect to an aircraft which has a lat lon but obviously at a specific height, a azmiuth and elevation look angle and also range to the point on ground ( all known ) .

[latout, lonout] = reckon(lat, lon, rng, az)

e.g from help section

dist = nm2deg(600) % convert nm distance to degrees

dist = 9.9933

pt1 = reckon(51.5,0,dist,315) % northwest is 315 degrees

pt1 = 57.8999 -13.3507

The reckon function seems to do near enough exactly what i want but does not take in account elevation angle ( i.e assumes both points are on the ground)

Is there any function similar that i can achieve being able to add in an elevation angle to the calculation, or change the reckon function in anyway?

Any help much appreciated

Answer 1

[arushi]

Hi Fraser,

To calculate the latitude and longitude of a point on the ground from an aircraft given its latitude, longitude, altitude, azimuth, elevation angle, and range to the point on the ground, you need to take into account the elevation angle to project the range onto the ground plane. The reckon function in MATLAB does not directly account for the elevation angle, but you can modify your approach to include this factor.

Here's a step-by-step method to achieve this:

1. Calculate the ground range: The ground range is the horizontal distance from the aircraft to the point on the ground. This can be derived using the elevation angle and the slant range (which is the direct line-of-sight distance to the point).
2. Use the reckon function: Once you have the ground range, you can use the reckon function to calculate the new latitude and longitude.

Hope this helps.