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If you happen to have a VR headset and are looking to play around with the toys described in the article, I recommend VTOL VR. It has pretty low system requirem

by oehpr 5y ago

If you happen to have a VR headset and are looking to play around with the toys described in the article, I recommend VTOL VR. It has pretty low system requirements, and takes advantage of VR to create a virtual hotas (It is much more effective than you would expect). The physics simulation is, to my understanding, very good. And everything described in this article is present in the game to be played around with. VTOL VR taught me about "Radar Notching". The article briefly mentions how radar can actively detect the doppler shift of targets. If you think about it, the doppler shift of the ground would be neutral, right? Or roughly the speed of the aircraft. So lets say you've been locked on by a fighter at high altitude and they've fired a radar seeker at you. Your backdrop is the ground, it can pick you out because you're moving so fast. So what you do is bank your aircraft to fly at a 90 degree angle to the oncoming missile. Now your doppler shift is the same as the ground and you blend in, the radar filters out the ground because of it's expected speed, which is now the relative speed you are moving. You get "notched out", and the missile will lose track.

t0mas88 5y ago
Radar is also very good at distance measurement so I guess this won't work for a real life rocket fired at a fighter jet. Because it's so easy to defeat this trick in the software.
- oehpr 5y ago
  I'm to understand that tricks like this are much less effective against more modern A2A missiles, so you might be right.
- sandworm101 5y ago
  A missile will generally not care about distance. What matters is direction/angle. Distance is irrelevant. Just keep pointing at the target and eventually you will get there, assuming you are faster. So the direction to the strongest reflection, or greatest doppler shift, or combination of both, will suffice to get the missile to the target even without range data.
  - wyager 5y ago
    > Just keep pointing at the target and eventually you will get there Surely they can't use this poor of an optimization strategy? If the target is moving perpendicular to you, you want to point slightly ahead of the target so you intercept them as quickly as possible.
    - klodolph 5y ago
      Yes, even old ordnance like the Sidewinder, which entered service in the mid-1950s, would aim ahead of the target.
    - jameshart 5y ago
      ‘Pointing at’ in this case means maintaining a constant bearing to target, with decreasing range. If anything it’s easier for a moving guidance system to achieve that than to point at the target.
      - giva 5y ago
        Link for clarification: https://en.wikipedia.org/wiki/Constant_bearing%2C_decreasing_range https://en.wikipedia.org/wiki/Constant_bearing%2C_decreasing...
        sandworm101 5y ago
        Except that, in the case of a missile, you cannot assume decreasing range. We assume that the missile knows to aim ahead of the target, but determining which way is ahead and which behind is tricky. If it is chasing a hotspot, a single point, getting that wrong means worsening your approach. A strait/boresight approach might not be ideal but it avoids the question over which offset is ahead and which behind the target.
        thrill 5y ago
        Continuously pointing directly at the target tends to result in the missile being unable to generate the needed turn rate at the conclusion of the intercept. If the missile has a large warhead, that might not matter so much, but air-to-air missiles tend to be small.
- angry_octet 5y ago
  Notching definitely works, it is used routinely in air combat. It is more effective at greater range because it's hard to maintain the same distance to a radar that is closing on you. The principal use is to break missile lock. It's less useful for disguising position, especially against opponents with AEW&C and data link. Breaking lock means reducing the doppler return to below the range gate threshold, and changing bearing to escape the Kalman filter that is predicting your position based on prior kinematics.
sandworm101 5y ago
But which radar to you beam against? The radar in the missile or the radar in the launching aircraft? Beam against one and you are not beaming against the other. You are probably dead so long as one of the two has you.
- nradov 5y ago
  During the initial fly out the missile will usually either be flying toward a set navigation point, or receiving data link guidance from the launching aircraft, or cueing off radar signals reflected by the target from the launching aircraft's radar (passive homing). You want to keep the missile's own radar switched off until fairly late in the engagement because it has limited battery power, narrow field of view, and will alert the target's radar warning receiver. With modern data links it's now possible in principle to provide target tracking updates from a different sensor (like IRST) or even a completely different aircraft. If done correctly the target won't even realize a missile is on the way until it's too late to evade.
  - angry_octet 5y ago
    It's sadly different to Top Gun, when lock on would involve switching to a different PRF and/or revisit rate. Now, if they don't turn away after you've launched it could be because their missile is already on the way... At closer range there is still the UV flare of the missile solid rocket burn, but detecting it depends on weather and aspect.
    - sandworm101 5y ago
      Or they could be cranking and that turn away is evidence that they have already launched against you.
      - angry_octet 5y ago
        If they crank it's because they have a shot off and they think you have a low Pk. Or they're bluffing and they have brass ovaries. It's nerve wracking just thinking about it.
platz 5y ago
Any thoughts on how VTOL VR compares to Falcon 4. Barring obvious upgrades like graphics, would you say it's strictly better, or does Falcon 4 still have some advantages?
- oehpr 5y ago
  Falcon 4 looks to be competing with DCS. Personally I've played neither. What VTOL VR does is use the VR environment to make an interactive cockpit. Rather than you memorizing a huge list of bindings, you just interact with the cockpit the way the pilots would. That memorization aspect is why I never really got into falcon 4 or DCS. And as a first mil sim flight game, if you have a headset, that's my recommendation.
  - jhomedall 5y ago
    Both DCS and Falcon BMS (actively maintained fork of Falcon 4) have fully clickable cockpits. You can also use keyboard shortcuts, of course. Falcon BMS example: https://www.youtube.com/watch?v=_mU2d3PbD78 https://www.youtube.com/watch?v=_mU2d3PbD78

by oehpr 5y ago

t0mas88 5y ago

Radar is also very good at distance measurement so I guess this won't work for a real life rocket fired at a fighter jet. Because it's so easy to defeat this trick in the software.

oehpr 5y ago
I'm to understand that tricks like this are much less effective against more modern A2A missiles, so you might be right.
sandworm101 5y ago
A missile will generally not care about distance. What matters is direction/angle. Distance is irrelevant. Just keep pointing at the target and eventually you will get there, assuming you are faster. So the direction to the strongest reflection, or greatest doppler shift, or combination of both, will suffice to get the missile to the target even without range data.
- wyager 5y ago
  > Just keep pointing at the target and eventually you will get there Surely they can't use this poor of an optimization strategy? If the target is moving perpendicular to you, you want to point slightly ahead of the target so you intercept them as quickly as possible.
  - klodolph 5y ago
    Yes, even old ordnance like the Sidewinder, which entered service in the mid-1950s, would aim ahead of the target.
  - jameshart 5y ago
    ‘Pointing at’ in this case means maintaining a constant bearing to target, with decreasing range. If anything it’s easier for a moving guidance system to achieve that than to point at the target.
    - giva 5y ago
      Link for clarification: https://en.wikipedia.org/wiki/Constant_bearing%2C_decreasing_range https://en.wikipedia.org/wiki/Constant_bearing%2C_decreasing...
      - sandworm101 5y ago
        Except that, in the case of a missile, you cannot assume decreasing range. We assume that the missile knows to aim ahead of the target, but determining which way is ahead and which behind is tricky. If it is chasing a hotspot, a single point, getting that wrong means worsening your approach. A strait/boresight approach might not be ideal but it avoids the question over which offset is ahead and which behind the target.
        thrill 5y ago
        Continuously pointing directly at the target tends to result in the missile being unable to generate the needed turn rate at the conclusion of the intercept. If the missile has a large warhead, that might not matter so much, but air-to-air missiles tend to be small.
angry_octet 5y ago
Notching definitely works, it is used routinely in air combat. It is more effective at greater range because it's hard to maintain the same distance to a radar that is closing on you. The principal use is to break missile lock. It's less useful for disguising position, especially against opponents with AEW&C and data link. Breaking lock means reducing the doppler return to below the range gate threshold, and changing bearing to escape the Kalman filter that is predicting your position based on prior kinematics.

sandworm101 5y ago

But which radar to you beam against? The radar in the missile or the radar in the launching aircraft? Beam against one and you are not beaming against the other. You are probably dead so long as one of the two has you.

nradov 5y ago
During the initial fly out the missile will usually either be flying toward a set navigation point, or receiving data link guidance from the launching aircraft, or cueing off radar signals reflected by the target from the launching aircraft's radar (passive homing). You want to keep the missile's own radar switched off until fairly late in the engagement because it has limited battery power, narrow field of view, and will alert the target's radar warning receiver. With modern data links it's now possible in principle to provide target tracking updates from a different sensor (like IRST) or even a completely different aircraft. If done correctly the target won't even realize a missile is on the way until it's too late to evade.
- angry_octet 5y ago
  It's sadly different to Top Gun, when lock on would involve switching to a different PRF and/or revisit rate. Now, if they don't turn away after you've launched it could be because their missile is already on the way... At closer range there is still the UV flare of the missile solid rocket burn, but detecting it depends on weather and aspect.
  - sandworm101 5y ago
    Or they could be cranking and that turn away is evidence that they have already launched against you.
    - angry_octet 5y ago
      If they crank it's because they have a shot off and they think you have a low Pk. Or they're bluffing and they have brass ovaries. It's nerve wracking just thinking about it.

platz 5y ago

Any thoughts on how VTOL VR compares to Falcon 4. Barring obvious upgrades like graphics, would you say it's strictly better, or does Falcon 4 still have some advantages?

oehpr 5y ago
Falcon 4 looks to be competing with DCS. Personally I've played neither. What VTOL VR does is use the VR environment to make an interactive cockpit. Rather than you memorizing a huge list of bindings, you just interact with the cockpit the way the pilots would. That memorization aspect is why I never really got into falcon 4 or DCS. And as a first mil sim flight game, if you have a headset, that's my recommendation.
- jhomedall 5y ago
  Both DCS and Falcon BMS (actively maintained fork of Falcon 4) have fully clickable cockpits. You can also use keyboard shortcuts, of course. Falcon BMS example: https://www.youtube.com/watch?v=_mU2d3PbD78 https://www.youtube.com/watch?v=_mU2d3PbD78