modelling a monostatic radar

Hi Honglei

Thank you for your previous response. Let me start at the beginning, I have a project, in it I am trying to use the Phased array tool box to make a tradeoff study in order to help to make a decision to acquire a new system or not.

I am basically comparing two different monostatic radars.

My approach is as follows; 1. Build to radar models as shown by the basic monostatic demo. 2. But use custom radar antenna i.e: hant = phased.CustomAntennaElement to build a particular antenna characteristics eg azimuth beamwidth and elevation. 3. Try to implement your answer in order to have total coverage of different approach angles around the ATC radar. 4. Incorporate different sources of competing echoes in the simulation and maybe clutter. 5. Implement the different processing techniques that the different product brochures talk about and see effect on performance of the radar.

My questions are as follows; 1. If the radar is rotating through 360 degress at a given rotation rate and radiating through the scan area, one does not know what the approach angle of the target is. How does this affect your proposed solution above? 2. Does one specify the following to simulate a custom radar with a given azimuth beamwidth, 1.4 deg, and elevation 2 deg. i.e hant.AzimuthAngles = -0.7:0.7, hant.ElevationAngles = -1:1; I have used the polar plot command it seems ok bt wanted to confirm. 3. Most of the demos I looked at analyse a situation without radar rotation like you said. what will be the effect of accounting for contant rotation?

Regards KJ Zwane

Answer 1

[Honglei Chen]

Hi Keketso,

For question 1, the solution I provided is independent of the approaching direction of the input signal, if that's what you are asking. I'm not hundred percent sure what you men by "one does not know what the approach angle of the target is" because we are talking about simulation here. We could assume that we have no such information when we process the data, but to synthesize the signal, we do need that approaching angle. If I didn't understand your question correctly, please let me know.

For question 2, the information you gave here isn't complete so I just have some general comment. If you are simply specifying the range of both azimuth and elevation beamwidth, and make the response all one within the beamwidth, you do get some sort of beam patten. However, if that is what you do, in my opinion, it may not be the best option because you now have a very discontinuity at the edge of the beam. I think a better approach will be to simulate since patterns in both azimuth and elevation directions based on the azimuth and elevation beamwidth, and then define the entire patten as the product of the two. This way you have a smooth pattern and it is a good approximation for a horn antenna.

For question 3, it is true that Phased Array System Toolbox currently does not have a rotating antenna example, but the general principle still applies. From what I can see, there are several things you should be cautious of:

1. because the antenna is rotating, it is very likely that the target return is fluctuating. You should choose correct model for the target.
2. because the antenna is rotating, the target is also not constantly illuminated. Hence, you only get the target return within certain dwell during each rotation. This would affect how many and which pulses you can integrate.

I hope this helps and please let me know if you need any additional information.

Regards,

Honglei