I hope this is the right place to ask a radar related question, otherwise I would be grateful for a pointer to the correct forum.
I want to compute the angular resolution of a radar system but so far I have found different formulas and I am not sure which one to choose. I am also wondering why there is a range dependency in some formulas while anothers I found just assumes the angular resolution to be proportional to the 3dB-Beamwidth, see last equation below.
Further it would be nice to know, where the following formulas are coming from and what their main underlying assumptions are.
I know this might be a lot to ask, but a brief explanation would be great since all of these formulas are some kind of "rules-of-thumb" as far as I understand.
One formula I found here:
To start with, let us assume that we can build an antenna as large as necessary to meet our azimuth resolution requirement. The rule of thumb governing antenna size is
dazimuth ≈ λR/L
where, dazimuth = resolvable distance in the azimuth direction, λ = wavelength of radar, R = range, L = length of the antenna.
Here is another formula, I found here
S_A >= 2Rsin(Θ/2)
Θ = antenna beamwidth (Theta)
SA = angular resolution as a distance between two targets
R = slant range aim - antenna [m]
Another document I only have as a hard copy computes the angular resolution as:
dazimuth ≈ kappa * BW
where, dazimuth = resolvable distance in the azimuth direction, kappa = is a real valued constant between 1 and 2, BW = is the 3dB-beamwidth.
Edit: I want to model the angular resolution of a uniform linear array with drone targets flying at approx. 100kmh at low altitude above ground.