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About nighthawk2174

  • Birthday 03/11/1999

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    BMS, DCS
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  1. The spparow's also home in on doppler, they track using a speedgate. This should provide good resistance against chaff considering how quickly they loose speed.
  2. Yeah this is what English bias commands are for, from the AIM-7E autopilot diagram I have the english bias commands are applied at the moment of wing unlock which occurs even before seeker lock on. It seems like that's not happening here super odd. Almost as if their reversed???
  3. Never heard of it having hprf, it’s a mprf radar. It does have a lprf mode.
  4. Note that the Jeff has HPRF which has better detection range.
  5. The issue here is that in MPRF when you feed the returns into the associated apparent range bins then feed that into the attached doppler bins a good portion of that clutter will fall into another doppler bin whereas the target will be in one range bin. This will reduce the amount of energy that the target return has to compete against to whatever happens to fall into the same doppler bin. The MLC is not all at the same doppler as the target and the larger the look angle and the larger the velocity of the missile the more that energy is distributed. Were in STT not search as well, currently it seems that the notch is 100kts'ish hopefully you can give the exact number. But In STT your tracking gates are going to be much much smaller then this. Typical values I see referenced are 15m/s in total width. And the missile should really only loose the tracking gate if the target is not competing with clutter. But that would mean that you could get a lot closer to the central MLC return (especially at close range and for high RCS say being side on or given your belly to the target) without loosing track. If not right on it if the noise is low such as in only very low look angles or low return clutter like calm seas. Also we can't ignore factors like integration time and PDI for S/N.
  6. Yeah seems this is part of the notch behavior discussed before: my thoughts on the matter are layed out in this thread.
  7. I'd seen some documents reference two different nose cons for the 7F one that is better for the sensor and one better for aero performance i'd just never seen the difference. Do we know which one was in more common use? edit: Didn't the 7M get another redesigned nose again from the 7F? From just one quick image grab it seems that it's closer in shape to the older but more aerodynamic nose cone:
  8. There will be at some point it will be able to go active on its own. Currently the only benefit is better chaff resistance.
  9. The AIM-120 has an INS so by default its going to know the targets location in 3D space. You could easily look for a split S based off of this information. We know from documentation that there is a method by which there are adjustments made to compensate for the split-S on the AIM-7. I highly doubt the amraam would not have something similar if not even better.
  10. According to razbam's galinette DCS was only returning a constant value for the RCS even when side on. I linked him to your post and I think he said he was going to talk to you. Are you sure this is implemented?
  11. Yeah i'm still a little fuzzy on this but don't rage bins come before the Doppler filters?
  12. Part of what's going on here too, aside from mprf stuff as i'm not quite up far enough in my reading to know the exact answer I know it can be done though. We can't ignore S/N either, i've seen missiles notched at less then two miles. Except that there's a ton of things that should make the target compete even against a large MLC. The STT nature of the track ensures that integration time is extremely high effectively infinite, monopulse itself also has S/N benefits, side on RCS will be huge as well, the employment of PDI will also help. The type of terrain would also be important: https://patents.google.com/patent/US4559537 method of tracking targets in MLC patented by Raytheon in 1985 right when AIM-120 development was in full swing. Also from earlier are you using 15deg for the beamwidth for the amraam? That's huge way beyond a reasonable value. MACE uses a value of ~3-4deg Edit: The video posted by Vatikus is exactly how you deal with mprf ambiguities i'm still working on understanding the exact mechanisms behind mprf but as shown in the vid it can be done easily. There's a reason MPRF is so widly used.
  13. PRF jitter has issues it reduces range what radars use now if PRF switching. You switch between a few distinct PRF's usually 3-4 and get the same effect without as many issues.
  14. You absolutly can in MPRF especially in a monopulse seeker with its extremely good range resolution, especially in mprf. And considering the amraam's lack of need for long range I don't doubt its pulse width isn't quite small fractions of a microsecond. Not to mention other techniques developed to break out closely spaced contacts. Which monopulse seekers are capable of determing and even partially solving for multiple contacts inside its resolution cell.
  15. So RCS increasing when side on is implemented now? Also I know that there are references even the AIM-7 docs to "anti-Split S logic". Exactly what this entails is not discused but its not hard to make a reasonable guess. Its almost certaintly just a damper put on the acceleration command if the targets angular position and velocity meet a certain set of criteria. As such the flight path would look like the red line below instead of green which is what it does now: You can solve for range ambiguity even in HPRF just use PRF switching. Sorta, HPRF seekers are highly ambigous in range so i'm not sure if the ku/ka band amraam seeker would even have an unamiguous range of even that far. Its hard to range gate with HPRF as due to the range ambiguities its hard to seperate clutter from the target when putting returns into the range bins. Exactly Ontop of all of this Monopulse systems are renound for massive S/N gains over even planar arrays. Which would help even more. And yes range to ground clutter and type should be factored in I don't know if it is currently.
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