June 16, 201411 yr I suspect more coherence between platforms RCS. Heh, yes, okay. I get that, but what of the issue of the simplicity of the model? What is the point of an intensive overhaul of the RCS values (and don't forget that it isn't just ships, but also submarines, aircraft, weapons, etc, in play) if we cannot even differentiate between radar types, target aspect, materials and shaping, clutter, etc.? Forgive me for being blunt, but having worked on the Harpoon Classic database since its very inception (since the DB was first cracked open and made accessible for editing), there is SO MUCH more to this issue than a few data entry fields. Return on investment (of time and energy) becomes a HUGE point of order for me.
June 16, 201411 yr Ok, thanks for the look, but I since realized that the radar model will not help much with checking the RCS values which is what started this topic. There is actually an abundance of radar model and equation published out there, but practically no experimental RCS examples and just one empirical formula thanks to Mr. Skolnik. Also for radar equation I can just stick to your RCS workbook (thanks!), this is anyway the best match for the GE model. I have a different thought process. I have no better source than the H4.1 Smarter Radar model so that would be my point of reference to build HCRCS numbers. If H4.1 says I detect that Dergach at 52nm then I twist the dial on the HCRCS value until the HC radar model gets the detect at 52nm. Build enough data points and your broader "corrections" become more obvious. To me it looks somewhat like you are drifting in the breeze with no anchor from which to build your case. Your anchor might not be H4.1 radar. Find an anchor and build from it. The graphs and statistics are amazing and engaging but they aren't showing me much beyond dedication and effort (both key, but not getting you very far from what I can see). Brad goes farther, should your talent be aimed at building a better model? I can't answer that, the existing model is manageable and maybe it is better to get a foundation there or maybe the more detailed model we all want is just as worthy.
June 16, 201411 yr Ok, thanks for the look, but I since realized that the radar model will not help much with checking the RCS values which is what started this topic. There is actually an abundance of radar model and equation published out there, but practically no experimental RCS examples and just one empirical formula thanks to Mr. Skolnik. Also for radar equation I can just stick to your RCS workbook (thanks!), this is anyway the best match for the GE model. I have a different thought process. I have no better source than the H4.1 Smarter Radar model so that would be my point of reference to build HCRCS numbers. If H4.1 says I detect that Dergach at 52nm then I twist the dial on the HCRCS value until the HC radar model gets the detect at 52nm. Build enough data points and your broader "corrections" become more obvious. To me it looks somewhat like you are drifting in the breeze with no anchor from which to build your case. Your anchor might not be H4.1 radar. Find an anchor and build from it. The graphs and statistics are amazing and engaging but they aren't showing me much beyond dedication and effort (both key, but not getting you very far from what I can see). Brad goes farther, should your talent be aimed at building a better model? I can't answer that, the existing model is manageable and maybe it is better to get a foundation there or maybe the more detailed model we all want is just as worthy. Fire for effect.
June 23, 201411 yr Author Fun reading ... but what's the objective? Guess I was asking for this when I posted just a shape of an idea but I was eager to share and had no more time on my hand. Anyway the objectives are: My immediate objective is to ask in a grounded way whether the Dergach RCS is too low. It seems too stealthy at 170 (38.6nm detection range vs APS-145 in HC) when compared to either the Coast Guard study (gives 20-36nm for the much lower performance APS-134 vs 1m2) or the H4.1 data (63nm SS range for APS-145 vs very small targets). I could not find any hint pointing at stealthy design, however I have practically no source on this. Next is to build grounded case (to discuss) that the smaller ships are too stealthy (too low RCS on average) in HCDB. E.g. many have Dergach-ish performance. Last I wanted to share the spreadsheet formula for RCS value calculation, I was pleasantly surprised how well the Skolnik function can be made to match the HCDB RCS values with light parametering. I see potential that the formula can be used to improve HCDB, either just to find the odd entries which need checking, or, possibly to regenerate RCS values for certain types of ships, for example if there is merit in 1. or 2. I do not see this last as a major overhaul of the RCS values, the function matches the current values pretty good (see the below graph how good), it would only add consistency across ship sizes where no other data presents itself for a specific class to have out-of-ordinary RCS value. To me it looks somewhat like you are drifting in the breeze with no anchor from which to build your case. Your anchor might not be H4.1 radar. Find an anchor and build from it. The graphs and statistics are amazing and engaging but they aren't showing me much beyond dedication and effort (both key, but not getting you very far from what I can see). ... Well, yes indeed, I found that there is almost no RCS data published outside of wargames. But then there is the Coast Guard study, which anchors the case for the APS-134 for 1m2 and 100m2 RCS real world ship targets. The Coast Guard study is just one reference, but the good match of HCDB with Skolnik generated values tells that these are generally good RCS functions, there is no need to change the shape of them, only we need to anchor this curve to the Coast Guard reference points. This is where the spreadsheet formula can come handy, it can be made to reasonably match the HCDB curve and then it can be easily shifted up/down to the Coast Guard anchor point(s) by just changing a constant one place in the spreadsheet. As example below is the DD and DDG subtypes curve, HCDB-130924 and Skolnik, all I did for the blue curve was that I checked the larger deviations and set appropriate "Stealth levels" where the HCDB description or Wikipedia info confirmed a RCS conscious design, this is why even most "spikes" are matching. There are few deviations left, these would be interesting to discuss and these would be the first candidates to get corrected/adjusted. Additionally, it is interesting that the HCDB curve suffers a steep drop in general for DD ships below 110m, this adds to point 2 I'm making above. I would now continue with specific examples for the correction candidates, only out of time for today.
June 24, 201411 yr The matching between the Skolnik and the HCDB curves is very impressive, aside the 110 meters-less ships. It's clearly the way for some minor adjusts.
June 24, 201411 yr Yep, some adjustment required. In other words, par for the course. Consider it on a long list of things to do in the HCDB and other databases. I'm not doing it for giggles, though, folks. If you're not writing scenarios to share with the community, why bother? (Enrique, that would NOT be directed at you, obviously).
July 12, 201411 yr Author Apparently I jumped the gun, it was not ok to upload Brad's HCDB with the RCS modification and the file has been removed from the downloads section. Apologies. Please find attached the suggested RCS changes in excel instead. Grumble Have posted modified HCDB-130924 commondb.res under the downloads section. Generally recalibrated ship RCS values based on the Skolnik function designed as posted earlier in this thread. Small size ships got a general increase of RCS. Few modern ships got significant reduction, e.g.: Overview RCS - ship length graph, original vs. modified "Stealth levels" are guess work based DB text description, Wikipedia and other web information on ship designs. And that is only for a small portion of them I had time to read after, any suggestions are welcome! Changes are listed in the attached excel. HCDBshipRCSMOD.zip
July 13, 201411 yr Apparently I jumped the gun, it was not ok to upload Brad's HCDB with the RCS modification and the file has been removed from the downloads section. Apologies. Please find attached the suggested RCS changes in excel instead. When I get time to review the suggested changes - and I have no reason to believe at this point that they aren't great (based on Grumble's extremely useful work) - they will be incorporated into the official version of the HCDB.
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