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Radar system modelling WRAP

Dear community,

I would like to create a new radar model in WRAP (v 2025). The radar is equipped with an Active Electronically Scanned Array (AESA) with given Field of Regard (FOR) in azimuth and elevation.

From the Altair WRAP 2025.0 User Guide Chapter 11.1 I found: "It is possible to define if the radar shall be directed to the calculation point or if the antenna direction
shall be fixed. The antenna may alternatively be set to scan mode in the horizontal and vertical plane."

So I am asking your help on the following:

What is the easiest way to create a new radar system, equipped with an AESA?
How can I model the scanning operation? I am not interested in the surveillance time but just the antenna beam will point in all the angles of the FOR.
Is there any tutorial showing how to create a new radar system? I have already considered the project Radar.wpr (WRAP Example Guide - Chapter 11)

Thanks in advance for your help and attention,

Regards

Luca

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Accepted answers

Zeina

Hi @LManica ,

" The scanning antenna seems to be related with the jammer not with the radar. In fact, when executing the Radio-optical visibility test nothing changes whatever the values I inserted in the scanning antenna menu. "

→ No, the Antenna settings I shared above are the Radar antenna. The list of jammers you see on the left is only to activate/disctivate the consideration of the jammers in the computations (right click on the jammer > click Set Jammer to set it on if you want).

So actually you should compare the RCS computations for the case where you activate the scanning in a given sector (Horizontal/vertical) and the case where the option is disactivated, in which case it scans 360 degrees. Here are the results comparing the case where I activates a horizontal scan from 0 to 180deg to that where the default is kept:

Note that in both cases I had the Jammers Off.

For the ROV computations, you can get multiple target height results by running the computation for different verticale heights, with each time the same given horizontal sector.

I am checking if we have a full model I can share with you. Meanwhile I hope the above is helpful.

Best,

Zeina

All comments

Zeina

Hi @LManica ,

I'm checking the details and will get back to you shortly with an example.

Zeina

You first add a radar station and integrate in your project, and then you can assign the corresponding scanning parameters you wish to implement. (see point 2.). To add a station you can use the LR station available in the WRAPdb Demo database.
The scanning can be activated from the Radar Coverage Tool parameters. To do so first Select the Radar Station from the Station list in the project, then go to Tools > Radio Coverage (or from the tool bar button). Go to the Transmission loss tab, find the Antenna section and activate the Use Scanning Antenna option and open the Settings below:

You can then control the horizontal and vertical scanning angles of the radar station during the coverage computations. You can also set the range of the scanning. This will allow you to set the FOR of the radar.

I recommend you test this with the Radar.wpr project for a start.

Best,

Zeina

You first add a radar station and integrate in your project, and then you can assign the corresponding scanning parameters you wish to implement. (see point 2.). To add a station you can use the LR station available in the WRAPdb Demo database.
The scanning can be activated from the Radar Coverage Tool parameters. To do so first Select the Radar Station from the Station list in the project, then go to Tools > Radio Coverage (or from the tool bar button). Go to the Transmission loss tab, find the Antenna section and activate the Use Scanning Antenna option and open the Settings below:

You can then control the horizontal and vertical scanning angles of the radar station during the coverage computations. You can also set the range of the scanning. This will allow you to set the FOR of the radar.

I recommend you test this with the Radar.wpr project for a start.

Best,

Zeina

LManica

Dear @Zeina, I am not 100 [%] sure your answer is correct.

The scanning antenna seems to be related with the jammer not with the radar. In fact, when executing the Radio-optical visibility test nothing changes whatever the values I inserted in the scanning antenna menu.

I was able to partially solve my problem in this way:

Edit Station > Radar > Radar Search Sectors - see picture 1 in the attached file
When executing the Radar coverage analysis - ROV in the calculation area menu select Search Sector(s) (picture 2b) instead of Around Station (picture 2a)
You can see the different results in Figure 3a and 3b

I am not still able to consider elevation scan so every suggestion is highly appreciated.

Thanks!

Zeina

"duplicate"

Zeina

Hi @LManica ,

Note that in both cases I had the Jammers Off.

For the ROV computations, you can get multiple target height results by running the computation for different verticale heights, with each time the same given horizontal sector.

I am checking if we have a full model I can share with you. Meanwhile I hope the above is helpful.

Best,

Zeina

LManica

Thanks @Zeina for your explanation. Very appreciated. My fault I was setting the beam scanning while running the ROV simulation.

Zeina

@LManica , you are welcome.

An extra clarification that might help understand better the difference between setting the sector search and the scanning antenna is that when you set a sector search, you are actually limiting your computation range to the sector limits. Whereas setting a scanning antenna, will limit the antenna range of the radar, but does not limit the sector in which the numerical computation is performed. The final effect might look similar, in the sense that you are seeing results in a given range only, but the principal is different. I hope this makes it clearer.

LManica

@Zeina thanks. Apologize me, but I am still missing one point about elevation scanning. Consider the following geometry (I hope I did not make any math mistake):

My radar antenna is pointing in \theta_p and it has a FOR. Given a target height, the radar detection range depends by:

Blind range
Maximal unambiguous range
FOR and pointing angle

In particular, is WARP able to automatically model point 3? I tried the following test (Radar.WPR):

and the final results is:

If the math is correct, I am expecting a reduction of the range since the radar is not able to "see" so far because FOR limitation. For the case I tried, the radar shall see "nothing" at this height (again I hope the math is correct), since h = 500 [m] (target altitude) - 122 [m] (radar altitude) - 24 (antenna height) [m] = 354 [m] and r_min = h/(tan(60)) = 204 [m] r_max = h/(tan(45)) = 354 [m]. But maybe I am missing some details or I am not modelling my use case appropriately. Can you please provide more details?

Additionally, (just my point of view) the Scanning Antenna Parameter menu is somehow misleading, because the scanning angle shall be referred to the radar antenna pointing angle not as the absolute value as it is (the antenna is pointing 306.274 [deg] azimuth and 0 [deg] in elevation])

Thanks for your precious help and support.

Regards

Zeina

Hi @LManica,

Let's try to clarify the main goal first. You mention the FOR of your radar, but for what target RCS do you want to compute it? What is the equation you are trying to model exactly? In the schematic you shared, there is only geometric values, nevertheless, the FOR is not only geometric. The Field of Range or the Detection Range of a radar depends on multiple factors, one of which is the RCS of the target, the minimum detectable single strength, etc. Once you have these clarified, the following will help you identify what to do with the tool to exactly model what you need. To give you an idea of the free space range computation for instance, it follows this formula:

you can check the different mathematical terms from the guide section 11.3.

Now regarding the analysis of the results you are viewing in the Transmission Loss computations you ran, this corresponds to the different RCS values a target should have at 500m agl, based on its radial location with respect to the radar position, to be detected by the radar. If you've kept the default scale of the color plot, then the red corresponds to 10m2, the yellow to 100m2, 1000m2:

In other words, the farther you go away from the radar, at 500m agl, the bigger a target should be to be detected. As we would expect.

Now, back to the FOR you mention, you should first check for which RCS you want to check it. Once you have that set, you can change the display of the results and set the threshold you need as below. Let's say 100m2. In this case your results will look like this:

and now this can be called a range detection of the radar for a target at 500m agl having an RCS of 100m2.

One last tip, in the Transmission loss tab parameters, you can ask for advice for which propagation model to run, in this case P.526 is recommended (click on Select next to the propagation model, then Advice).

Going back to the effect of the scanning range of the antenna, if you want to push this analysis further, you can compare, for the same scenario, the result you'd obtain with a different scanning angular range. For instance here, I changed the vertical scan from 45-60 to 0-60, I have now a larger detection range, as expected:

Best,

Zeina

LManica

Hi @Zeina ,

thanks for your answer, but I am still missing a point. If my antenna beam (better the EM wave transmitted by the radar antenna) cannot reach a target for some geometrical reasons, the radar cannot detect a target whatever its RCS. In fact, in a more precise radar equation, Gt and Gr (the gain of the transmitting and receiving antenna) have a dependance from theta (elevation) and phi (azimuth) angle. So, if the antenna gain is 0 for some angles (and as a first approximation we can think so outside the main beam) for those angles no target can be detect.

This is consistent when I set the beam to be scanned in azimuth scanning from 0 to 180 [deg].

I agree with you that changing the beam scanning in elevation will increase the detection range but the tool (again maybe I did something wrong with the math) is not plotting what I am expecting.

Going back to the case in which the scan in elevation is (45; 60) [deg] and the target agl is 500 [m], the radar should detect a target (supposing the RCS is big enough) only if it is located in the range (204, 354) [m], because the radar antenna is not pointing outside this range (Gt and Gr = 0 for theta < 45 [deg], theta > 60 [deg]). So since I set the minimum distance of my radar (Edit Station menu) to 1000 [m], I should see nothing.

On the other hand, if the scan in elevation is set to (0, 60) [deg], the maximal "geometrical" range increases to +infinity, and the detection now depends by the RCS of the target. In this case what you showed seems to be correct.

Zeina

Hi @LManica ,

Let's meet and discuss all the points, it would be more efficient. Can you create a support ticket referencing this exchange?

Best,

Zeina

LManica

Done. Thanks!