50 Calibre Guided Bullets

[DBT]

It needs quite rapid adjustments in trajectory. Considering the velocity of the projectile and the target is about a thousand yards, travel time is probably around one second.

 

[barbos]

It needs quite rapid adjustments in trajectory. Considering the velocity of the projectile and the target is about a thousand yards, travel time is probably around one second.

Second is an eternity for high speed camera and a computer.
Even ordinary 60 fps camera is probably good enough.

 

[DBT]

It needs quite rapid adjustments in trajectory. Considering the velocity of the projectile and the target is about a thousand yards, travel time is probably around one second.

Second is an eternity for high speed camera and a computer.
Even ordinary 60 fps camera is probably good enough.

Sure, but there must be a mechanical systems response such as 'firing the thrusters' on the projectile, left, right, up, down, in order to adjust trajectory.

 

[barbos]

Second is an eternity for high speed camera and a computer.
Even ordinary 60 fps camera is probably good enough.

Sure, but there must be a mechanical systems response such as 'firing the thrusters' on the projectile, left, right, up, down, in order to adjust trajectory.

Thrusters? there are no thrusters, more likely some kind of piezoelectric fins. and I doubt there is that many adjustments. from the video it looks like it is corrected at the end of the trajectory, near target.
maybe 3-4 cycles of adjustments, no big deal.

 

[bilby]

Obviously they just clip the bullet to the green line you can see on the video.

 

[DBT]

Sure, but there must be a mechanical systems response such as 'firing the thrusters' on the projectile, left, right, up, down, in order to adjust trajectory.

Thrusters? there are no thrusters, more likely some kind of piezoelectric fins. and I doubt there is that many adjustments. from the video it looks like it is corrected at the end of the trajectory, near target.
maybe 3-4 cycles of adjustments, no big deal.

By 'thrusters' I meant the means by which adjustments to trajectory are made. In this case the means by which the fins are moved with such rapid response time as to alter trajectory in microseconds.

Obviously it is being done successfully, so it is an impressive technical achievement.

 

[barbos]

Thrusters? there are no thrusters, more likely some kind of piezoelectric fins. and I doubt there is that many adjustments. from the video it looks like it is corrected at the end of the trajectory, near target.
maybe 3-4 cycles of adjustments, no big deal.

By 'thrusters' I meant the means by which adjustments to trajectory are made. In this case the means by which the fins are moved with such rapid response time as to alter trajectory in microseconds.

Obviously it is being done successfully, so it is an impressive technical achievement.

Where do you get microseconds?
at best it's tens of milliseconds. And do you know how many adjustments DVD player head does in a second?

 

[hurtinbuckaroo]

Well, regardless of whether or not it is smooth, it does not spin. it's basically a dart.

So it's fired from a standard rifle, which I would expect to impart spin. How does it avoid being spun, or counteract the spin?

 

[barbos]

Well, regardless of whether or not it is smooth, it does not spin. it's basically a dart.

So it's fired from a standard rifle, which I would expect to impart spin. How does it avoid being spun, or counteract the spin?

Don't know, maybe it's compound bullet of some sort.
But maybe it's rotating, I mean they show ordinary bullet illustration.

Rotating bullet with fins will not work of course.

 

[NobleSavage]

So it's fired from a standard rifle, which I would expect to impart spin. How does it avoid being spun, or counteract the spin?

Don't know, maybe it's compound bullet of some sort.
But maybe it's rotating, I mean they show ordinary bullet illustration.

Rotating bullet with fins will not work of course.

What if you had a smooth bore and corkscrew like fins?

 

[bigfield]

My guess is that the projectile is segmented: while the widest cylindrical segment spins, the rest of the projectie does not roll at all. This allows the bullet to be fired from a rifled barrel.

Two other cylindrical segments with high friction patches rotate to swing the projectile like a cricket ball, in whichever direction is required.

 

[Loren Pechtel]

So they are mini ballistic missiles...no rifling needed.

A better comparison is the Copperhead artillery round. We saw it in operation in Battle Los Angeles (although the guns were off-screen. The shells they were guiding in on the mothership were Copperheads.)

- - - Updated - - -

I was curious how the bullet knew what the target was so I read a few DARPA descriptions of the system. They, of course, didn't say exactly how it worked but the best I could figure is that it is essentially like the JDAM precision guided gravity bombs or the Hellfire missiles that were so effective. It looks like the target needs to be illuminated with a laser and the bullet directs itself to the laser spot. So someone needs to hold the laser on the target so the bullet will adjust itself to correct for wind, target movement, aiming error, etc.

Nitpick: It's not going to do anything about aiming error. If you're off target you're off target. The laser spot simply ensures the round actually goes where you point it, it does nothing to help you point it.

 

[skepticalbip]

I was curious how the bullet knew what the target was so I read a few DARPA descriptions of the system. They, of course, didn't say exactly how it worked but the best I could figure is that it is essentially like the JDAM precision guided gravity bombs or the Hellfire missiles that were so effective. It looks like the target needs to be illuminated with a laser and the bullet directs itself to the laser spot. So someone needs to hold the laser on the target so the bullet will adjust itself to correct for wind, target movement, aiming error, etc.

Nitpick: It's not going to do anything about aiming error. If you're off target you're off target. The laser spot simply ensures the round actually goes where you point it, it does nothing to help you point it.

Not according to DARPA. That was one of the tests they showed. They intentionally aimed off-target and the bullet corrected in flight to hit the target. It is one of the things I was curious about how the bullet knows what the target is in the system. Does it take two? As in a sniper team there is the spotter and the shooter. With this new system would the spotter illuminate the target with the laser?

ETA:

http://www.darpa.mil/NewsEvents/Releases/2014/07/10a.aspx

DARPA’s Extreme Accuracy Tasked Ordnance (EXACTO) program recently conducted the first successful live-fire tests demonstrating in-flight guidance of .50-caliber bullets. This video shows EXACTO rounds maneuvering in flight to hit targets that are offset from where the sniper rifle is aimed. EXACTO’s specially designed ammunition and real-time optical guidance system help track and direct projectiles to their targets by compensating for weather, wind, target movement and other factors that could impede successful hits.

 

[Loren Pechtel]

Nitpick: It's not going to do anything about aiming error. If you're off target you're off target. The laser spot simply ensures the round actually goes where you point it, it does nothing to help you point it.

Not according to DARPA. That was one of the tests they showed. They intentionally aimed off-target and the bullet corrected in flight to hit the target. It is one of the things I was curious about how the bullet knows what the target is in the system. Does it take two? As in a sniper team there is the spotter and the shooter. With this new system would the spotter illuminate the target with the laser?

ETA:

http://www.darpa.mil/NewsEvents/Releases/2014/07/10a.aspx

DARPA’s Extreme Accuracy Tasked Ordnance (EXACTO) program recently conducted the first successful live-fire tests demonstrating in-flight guidance of .50-caliber bullets. This video shows EXACTO rounds maneuvering in flight to hit targets that are offset from where the sniper rifle is aimed. EXACTO’s specially designed ammunition and real-time optical guidance system help track and direct projectiles to their targets by compensating for weather, wind, target movement and other factors that could impede successful hits.

This makes no sense unless the shooter and the guider are two different people--and in that case I would call where the guide beam is pointed to be the target, not where the rifle is aimed.

 

[DBT]

By 'thrusters' I meant the means by which adjustments to trajectory are made. In this case the means by which the fins are moved with such rapid response time as to alter trajectory in microseconds.

Obviously it is being done successfully, so it is an impressive technical achievement.

Where do you get microseconds?
at best it's tens of milliseconds. And do you know how many adjustments DVD player head does in a second?

A DVD player does not require trajectory adjustments for a projectile traveling at something like 2800fps with a travel time that's probably less than a second, and the final adjustment may be three quarters of the way to the target. That is why it's quite a technical achievement, albeit being applied to questionable ethical purposes.

 

[barbos]

Where do you get microseconds?
at best it's tens of milliseconds. And do you know how many adjustments DVD player head does in a second?

A DVD player does not require trajectory adjustments for a projectile traveling at something like 2800fps with a travel time that's probably less than a second, and the final adjustment may be three quarters of the way to the target. That is why it's quite a technical achievement, albeit being applied to questionable ethical purposes.

Traveling speed is irrelevant. it's how many times per second you need to make an adjustment. So DVD player or hard drive do you much more often than this bullet.
And in the case of the bullet I would not be surprised if it does just one adjustment, so there is no loop, at distance of 100 meters from the target you measure how much off you are and then execute one adjustment and that's it. And piezoelectric actuators can work in megahertz range, not that it's needed here.
So this is not big deal. What appears to be a big deal here is apparent claim that this thing can be shot from completely ordinary rifle.
Bullets are not that fast when it comes to that kind of things.

 

[DBT]

A DVD player does not require trajectory adjustments for a projectile traveling at something like 2800fps with a travel time that's probably less than a second, and the final adjustment may be three quarters of the way to the target. That is why it's quite a technical achievement, albeit being applied to questionable ethical purposes.

Traveling speed is irrelevant. it's how many times per second you need to make an adjustment. So DVD player or hard drive do you much more often than this bullet.
And in the case of the bullet I would not be surprised if it does just one adjustment, so there is no loop, at distance of 100 meters from the target you measure how much off you are and then execute one adjustment and that's it. And piezoelectric actuators can work in megahertz range, not that it's needed here.
So this is not big deal. What appears to be a big deal here is apparent claim that this thing can be shot from completely ordinary rifle.
Bullets are not that fast when it comes to that kind of things.

Centre fire rounds are around the 3000fps mark, which is not slow. How much adjustment the projectile needs to make depends on what the target is doing, wind factor, target movement. Even if the target is stationary, wind is a factor, that alone may cause a miss at long range. A moving target makes it far harder shot, the speed that the target is moving, how it is moving, erratic, straight line, etc, are all significant factors for long range shooting.

 

[barbos]

Traveling speed is irrelevant. it's how many times per second you need to make an adjustment. So DVD player or hard drive do you much more often than this bullet.
And in the case of the bullet I would not be surprised if it does just one adjustment, so there is no loop, at distance of 100 meters from the target you measure how much off you are and then execute one adjustment and that's it. And piezoelectric actuators can work in megahertz range, not that it's needed here.
So this is not big deal. What appears to be a big deal here is apparent claim that this thing can be shot from completely ordinary rifle.
Bullets are not that fast when it comes to that kind of things.

Centre fire rounds are around the 3000fps mark, which is not slow.

"Fast" is relative, in this particular case it's slow.

How much adjustment the projectile needs to make depends on what the target is doing, wind factor, target movement. Even if the target is stationary, wind is a factor, that alone may cause a miss at long range. A moving target makes it far harder shot, the speed that the target is moving, how it is moving, erratic, straight line, etc, are all significant factors for long range shooting.

at 100 meters wind is not a factor.
and moving of the target is not a factor in itself here. It's movement change, and at 100 meters it's not a factor either.
Think of it as shooting from 100 meters, if you are an excellent sniper (and computers are) you can shoot anything with a dumb bullet just fine.

 

[DBT]

But this system is no meant for a 100 metres. More likely for shots well beyond 500 metres You could use a musket and open sights for 100 metre shots at man sized targets.

 

[barbos]

But this system is no meant for a 100 metres. More likely for shots well beyond 500 metres You could use a musket and open sights for 100 metre shots at man sized targets.

it shoots 2 km, but it adjusts when it is pretty close to the target, before that it's just flies freely.