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  • moon_light
    Rank 5 Registered User
    • May 2012
    • 1033

    Originally posted by stealthflanker View Post
    Should be correct. although i wonder why it has different arrangement to the one in the possible source material, David Adamy's EW-101 book. This is the equation look like in the book.
    I don't understand their final formula, what is Rt and R? how did they get rid of RCS, ERP in their final formula?

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    Following their result, seft protect jamming is extremely effective?, any aircraft can get the fight to visual range with a jamming pod?
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    Do you think F-16 with ALQ-184 is adequate to get the tracking range of Zaslon-AM or IRBIS-E to visual range?
    Last edited by moon_light; 20th February 2019, 05:47.

    Comment

    • stealthflanker
      Rank 5 Registered User
      • Sep 2015
      • 1026

      Originally posted by moon_light View Post
      I don't understand their final formula, what is Rt and R? how did they get rid of RCS, ERP in their final formula?
      They should be the range to target from the radar and R one is range of jammer to radar. and it is NOT the final equation. The last term is the instruction that to get the result in the unit of distance, you have to use the base 20 anti logarithm to convert the result of previous equation from Decibel value back to the unit of distance (miles, NMI, km etc)


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      Following their result, seft protect jamming is extremely effective?, any aircraft can get the fight to visual range with a jamming pod?
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      Do you think F-16 with ALQ-184 is adequate to get the tracking range of Zaslon-AM or IRBIS-E to visual range?
      an important note is that concept of "burn through" range does not apply to self protection jammer as it use different technique to get their job done. Burn through range only applicable to noise jamming situation. The equation may provide answer BUT that does not indicate the radar cant do anything on the presence of self protection jammer.

      To quantify the effect of the self protection jamming, one have to know the radar's ECCM's capability and availability of certain counter-countermeasure mode. Say ALQ-184 may have repeater mode and "double" RGPO & VGPO modes. If Irbis or Zaslon have say, "VGPO-RGPO Reset" or can quickly re-acquire target after the jammer "cuts down" the acquisition process. Then it can quickly reestablish track on the F-16 and engage.

      Comment

      • moon_light
        Rank 5 Registered User
        • May 2012
        • 1033

        Originally posted by stealthflanker View Post
        an important note is that concept of "burn through" range does not apply to self protection jammer as it use different technique to get their job done. Burn through range only applicable to noise jamming situation. The equation may provide answer BUT that does not indicate the radar cant do anything on the presence of self protection jammer.
        To quantify the effect of the self protection jamming, one have to know the radar's ECCM's capability and availability of certain counter-countermeasure mode. Say ALQ-184 may have repeater mode and "double" RGPO & VGPO modes. If Irbis or Zaslon have say, "VGPO-RGPO Reset" or can quickly re-acquire target after the jammer "cuts down" the acquisition process. Then it can quickly reestablish track on the F-16 and engage.
        What if the ECM pod uses noise jamming? i remember that mode is available on ALQ-184 and ALQ-131 pod?
        What if there is a MALD-J nearby and it use noise jamming to protect F-16? what is the option to break through the noise jamming?
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        • stealthflanker
          Rank 5 Registered User
          • Sep 2015
          • 1026

          Originally posted by moon_light View Post
          What if the ECM pod uses noise jamming? i remember that mode is available on ALQ-184 and ALQ-131 pod?
          What if there is a MALD-J nearby and it use noise jamming to protect F-16? what is the option to break through the noise jamming?
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          Then it can be burned through as standoff jamming. Except this time the jammer is co-located.

          The Multiple number of noise jamming can be countered through processing. like say generation of jammer strobes, with hope that some targets is not covered.

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          Other countermeasures are available in this list :

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          Otherwise is to engage the jammer, which is why we have trend of increasing munitions quantity in today's ground based SAM's

          Comment

          • moon_light
            Rank 5 Registered User
            • May 2012
            • 1033

            Originally posted by stealthflanker View Post
            Then it can be burned through as standoff jamming.
            I got it, but what distance do you expect/estimate IRBIS-E/ZASLON to burn through MALD-J jamming, if the target being protected is an F-16?, is the noise jamming enough to get it to visual range?

            Comment

            • garryA
              Rank 5 Registered User
              • Dec 2015
              • 1120

              ^ i tried and get 7.5 km

              Comment

              • stealthflanker
                Rank 5 Registered User
                • Sep 2015
                • 1026

                To do estimate one must use the good value for the radar. For the Standoff jamming case. We need to know the Sidelobe level of the Irbis and Zaslon. This information however is kinda hard to find but estimates are available. a Good generic rule of thumb to estimate sidelobe level of an array antenna is to divide 1 with number of elements, this rule of thumb however assume uniform illumination. The elements itself can be easily estimated with the AESA radar calculator's "TR Module number" spreadsheet. All need to be done is to input the antenna vertical and horizontal diameter to antenna area finder. and From there one can work out the estimate frequency band for the radar, which in here we take as 9300 MHz, as can be seen here :

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                Then we can estimate the number of radiating elements of the Irbis and Zaslon with following result :

                Irbis-E : 1960
                Zaslon : 3267

                From there we then can estimate average sidelobe level as follows :

                Irbis : 10*LOG(1/1960) = -32.9 dB
                Zaslon : 10*LOG(1/3267) = -35.14 dB

                The emitted power would be :
                Irbis-E : 20 Kilowatt or 20000 Watt or about 73 dBm
                Zaslon : 10 Kilowatt or 10000 Watt or about 70 dBm

                The antenna gain can be estimated from the number of elements or findings in open source.
                Zaslon : 37 dB

                For Irbis tho, some other estimate have to be made. We only know its diameter. then we need to calculate beamwidth. Easily be done through number of elements :
                We assume uniform illumination, thus the beamwidth coefficient would be 0.886. The antenna beamwidth is then calculated to be :

                BWirbis=0.886*(100/SQRT(1960))
                BWirbis= 2 Degrees

                Then using K barton's approximation, we can calculate the antenna gain as following 10*LOG(30000/(2*2)) = 38.7 dB.

                Armed with those values. We can then estimate burn through range. With following result.

                Irbis-E
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                Zaslon :
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                You can download the spreadsheet i made for above calculation here :

                http://www.mediafire.com/file/cp58n9...ff+Jammer.xlsx
                Last edited by stealthflanker; 20th February 2019, 19:10.

                Comment

                • panzerfeist1
                  Rank 6 Registered User
                  • Feb 2018
                  • 413

                  stealthflanker

                  just 2 things I need to know before downloading your excel sheet. What is the typical radar pulse repetition frequency and pulse width used by radar? Is there a way to determine these based on other factors(in layman terms)? Either way can you give me an average estimated range for radar pulse repetition frequency and pulse width for modern aircrafts?

                  Lets also say theoretically https://ieeexplore.ieee.org/document/6217012 I have this ultra high resolution to distinguish someone's face from 400kms away. Does resolution effect the RCS of a target? For example I have a very high resolution SAR to see a 1m2 target from 400kms away on radar would ultra-high resolution give me the ability to see a smaller RCS target than this?
                  Last edited by panzerfeist1; 21st February 2019, 05:15.
                  I thought the fall of western civilization was a tragedy, now I realize it's a comedy.

                  Comment

                  • garryA
                    Rank 5 Registered User
                    • Dec 2015
                    • 1120

                    Originally posted by stealthflanker View Post
                    You can download the spreadsheet i made for above calculation here :
                    http://www.mediafire.com/file/cp58n9...ff+Jammer.xlsx
                    I made one for self protection. Download here: https://ufile.io/s72e3
                    5 Megawatt radar
                    10 Watt jammer
                    Target RCS: 0.01 m2
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                    Last edited by garryA; 21st February 2019, 04:37.

                    Comment

                    • stealthflanker
                      Rank 5 Registered User
                      • Sep 2015
                      • 1026

                      Originally posted by panzerfeist1 View Post
                      stealthflanker

                      just 2 things I need to know before downloading your excel sheet. What is the typical radar pulse repetition frequency and pulse width used by radar? Is there a way to determine these based on other factors(in layman terms)? Either way can you give me an average estimated range for radar pulse repetition frequency and pulse width for modern aircrafts?
                      That depends on operating mode. Selecting what's necessary is actually a complex process involving many factors. The best one can do in layman's term is to find data for other radar and apply it.

                      The data however can be easily found in good forum such as Secret Project's avionics section. Or you can find it on books about radar. I also hosted a table containing modes of typical fighter radar which you can see typical PRF and pulsewidth used.

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                      • panzerfeist1
                        Rank 6 Registered User
                        • Feb 2018
                        • 413

                        Thank you, sorry I edited the 2nd question. You do not have to answer it if you want.
                        I thought the fall of western civilization was a tragedy, now I realize it's a comedy.

                        Comment

                        • panzerfeist1
                          Rank 6 Registered User
                          • Feb 2018
                          • 413

                          I swear this will be my last time asking a question regarding the AESA calculator. I do not know if its a user error on my part or this sheet does not calculate RCS distance when narrowing or widening beams.

                          https://www.webcitation.org/6Qpsm5PU...eek_010807.pdf
                          The F-22s radar range is only [officially] described as being more than 100 mi. However, its thought to be closer to 125150 mi., which is much further than the standard F-15s 56 mi. radar range. New, active electronically scanned radar technology - optimized for digital output - is expected to soon push next-generation radar [the AN/APG77v1] ranges, in narrow beams, out to 250 mi.
                          The APG-77v1 with newer
                          GaAs
                          modules provides a range of 250 mi (400 km) or more; this is believed to be possible due to the use of more narrow beams
                          and can cue radar emissions to be confined to a
                          narrow beam
                          (down to 2 by 2 in azimuth and elevation) to increase stealth.




                          Even the Nebo-M with 360 degrees for a 1m2 target shows 480km but narrow the beam to 90 degrees that distance increases to 510kms.
                          Is it too much trouble to ask you if there is a possibility you could update an excel sheet calculating the RCS distance by either widening or narrowing azimuth radar beams(Or I just do not have the know how or its a screw up on my part)? For example I put 2000 T/R modules with 10 watts for modules, than put 1m2 for the target RCS, without changing the other properties(assuming this is the an/apg-77v1 calculations). So for horizontal beam I put 120 degrees, and vertical I put 12 degrees, 90% lock on I got 217kms. than narrowed the beam for both 2 by 2 degrees I got 179kms while the sources I have regarding the SU-35 and F-22 tell me if I narrow my beams I spot the same target more far away. Is there another calculation to do this in which you have for your sources, if so is it possible to update an excel sheet(while keeping it simple and stupid for users like me) by the use of narrowing beams and seeing targets more far away?
                          Last edited by panzerfeist1; 21st February 2019, 20:03.
                          I thought the fall of western civilization was a tragedy, now I realize it's a comedy.

                          Comment

                          • stealthflanker
                            Rank 5 Registered User
                            • Sep 2015
                            • 1026

                            Originally posted by panzerfeist1 View Post
                            I swear this will be my last time asking a question regarding the AESA calculator. I do not know if its a user error on my part or this sheet does not calculate RCS distance when narrowing or widening beams.
                            You can specify the scan sector easily in the sheet.

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                            Reducing scan sector however may help extending the range. But one must also consider the increasing amount of integration loss which will wash the range advantages.

                            Your sources also does not specify many things considered in the calculator. E.g they don't specify their detection probability. and dwell time (how long the beam stays in the search sector) So you can't really "re-create" the same condition mentioned in your source with the calculator.
                            Last edited by stealthflanker; 22nd February 2019, 09:43.

                            Comment

                            • RALL
                              Rank 5 Registered User
                              • Aug 2017
                              • 215

                              Originally posted by garryA View Post
                              I made one for self protection. Download here: https://ufile.io/s72e3
                              5 Megawatt radar
                              10 Watt jammer
                              Target RCS: 0.01 m2
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                              Target rcs from who?

                              From airplane which is jammed or Rcs from own airplane?

                              Comment

                              • stealthflanker
                                Rank 5 Registered User
                                • Sep 2015
                                • 1026

                                Originally posted by panzerfeist1 View Post

                                Lets also say theoretically https://ieeexplore.ieee.org/document/6217012 I have this ultra high resolution to distinguish someone's face from 400kms away. Does resolution effect the RCS of a target? For example I have a very high resolution SAR to see a 1m2 target from 400kms away on radar would ultra-high resolution give me the ability to see a smaller RCS target than this?

                                Resolution helps you identify the target by distinguishing various parts of it and allow you to build imagery out of it. and no it does not affect target RCS.



                                Target rcs from who?

                                From airplane which is jammed or Rcs from own airplane?
                                It's clearly the target aircraft that do the jamming.
                                The equation for self protection jamming presented in the book assumes that the jammer can always be in the mainlobe of the victim radar e.g you're being locked. With this the jammer will always have the advantage of injecting its techniques which will not be/seldom noise but RGPO etc.

                                Target RCS have little meaning for self protection as it will always be lower in terms of magnitude of power compared to what being emitted by the jammer.


                                -----------------------------
                                Future works for AESA radar calculator :
                                -more refined path propagation
                                -signal processor, time to introduce what is pulse doppler or MTI.
                                -Clutter (Sea, Land, Rain)
                                -Auto PRF select (user no longer have to specify PRF, the sheet will generate it instead based on target velocity or some general requirement like 95% visibility etc) It will instead prompt user to select "High, medium or low" PRF

                                Evaluation of clutter and signal processor is rather bit complex and specific as it may require user to actually specify some variables like target speed. The radar equation for those can also be no longer closed term, but rather have to be analyzed iteratively. It will be somewhat like this in appearance :

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                                This is a simplified model i use to estimate detect ability of target in sea clutter for an anti ship missile. The simplified equation is used and as seen the target is detectable in sea state 0-4 (i skipped sea state 1 as the base data i use for the clutter model is inaccurate) With doppler or MTI processing.

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                                Above is the example of rain clutter evaluation , as seen i need to specify detection range first.

                                The way of implementation i envisaged atm is to actually use the detection range from the calculation and later "evaluate" it using the user supplied "Processor improvement factor" to see if the radar can detect the target at specified range. If it cannot detect it then the sheet will look into similar signal strength to range table as i provided in the first image, then give range value where the signal strength exceeded the required threshold which in this sheet i would assume to be the same as one in thermal noise environment.


                                Attached Files

                                Comment

                                • panzerfeist1
                                  Rank 6 Registered User
                                  • Feb 2018
                                  • 413

                                  stealthflanker

                                  Hate to be a bother but is there a possibility to make an excel sheet that tells you what RCS size there is in close or farther ranges? Example there is a 1m2 target at 400kms however if I lower that target to .0001m2 what range would it be or lets say I track a .01m2 target at 400kms away than what distance will I see a .0001m2 target at? Is this feasible to do? And if so do you have plans to make such a project and if not can you dumb down the equation regarding this task? Thanks if you do or if you know any other user that can do this.
                                  I thought the fall of western civilization was a tragedy, now I realize it's a comedy.

                                  Comment

                                  • stealthflanker
                                    Rank 5 Registered User
                                    • Sep 2015
                                    • 1026

                                    Originally posted by panzerfeist1 View Post
                                    stealthflanker

                                    Hate to be a bother but is there a possibility to make an excel sheet that tells you what RCS size there is in close or farther ranges? Example there is a 1m2 target at 400kms however if I lower that target to .0001m2 what range would it be or lets say I track a .01m2 target at 400kms away than what distance will I see a .0001m2 target at? Is this feasible to do? And if so do you have plans to make such a project and if not can you dumb down the equation regarding this task? Thanks if you do or if you know any other user that can do this.
                                    It's very hard to understand what you mean but i think i know. For attempt to obtain value of RCS based on detection range, one can simply run the 4th root rules in reverse for that.

                                    Target RCS= (Reference RCS/Reference Detection range^4)*Target Detection Range ^4

                                    Following is the example :

                                    We have a radar with following capability :
                                    Detection range for 3 sqm target : 250 km

                                    A contact is detected at 50 km, what is the RCS of the target ?

                                    Then we run it :

                                    Target RCS= (3/250^4)*50^4
                                    Target RCS= 0.0048 sqm.


                                    Comment

                                    • RALL
                                      Rank 5 Registered User
                                      • Aug 2017
                                      • 215

                                      Originally posted by panzerfeist1 View Post
                                      stealthflanker

                                      Hate to be a bother but is there a possibility to make an excel sheet that tells you what RCS size there is in close or farther ranges? Example there is a 1m2 target at 400kms however if I lower that target to .0001m2 what range would it be or lets say I track a .01m2 target at 400kms away than what distance will I see a .0001m2 target at? Is this feasible to do? And if so do you have plans to make such a project and if not can you dumb down the equation regarding this task? Thanks if you do or if you know any other user that can do this.
                                      I have it, it is like stealthflanker tells.

                                      Its simple, but i think it is what you are looking.

                                      How do you want i send you the file?...inside this post do not let me upload xlsx extension
                                      Last edited by RALL; 20th May 2019, 20:12.

                                      Comment

                                      • stealthflanker
                                        Rank 5 Registered User
                                        • Sep 2015
                                        • 1026

                                        just put it on google drive or some other filehosting service.

                                        Comment

                                        • panzerfeist1
                                          Rank 6 Registered User
                                          • Feb 2018
                                          • 413

                                          Rall you are a great help but I will take stealth flankers calculation response. Thank you guys for being great resources.
                                          I thought the fall of western civilization was a tragedy, now I realize it's a comedy.

                                          Comment

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