# Can MANPADS lead a target? **URL:** \ **Category:** Factual Questions\ **Created:** [March 16, 2022, 6:23pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201 "2022-03-16T18:23:56Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [March 16, 2022, 6:23pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/1 "2022-03-16T18:23:56Z")
Do Man-Portable Air Defence System (MANPADS) have the ability to lead their targets, like a hunter shooting at ducks? Or do they head straight for the target and chase it? ---
**Author:** ![griffin1977](https://avatars.discourse-cdn.com/v4/letter/g/977dab/32.png) [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Post date:** [March 16, 2022, 6:29pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/2 "2022-03-16T18:29:30Z")
That’s been pretty much the point of every automated aiming system since the targeting computers of WW2, so I’d be surprised if it didn’t. ---
**Author:** ![Omniscient](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omniscient/32/3290_2.png) [@Omniscient](https://boards.straightdope.com/u/Omniscient)\ **Post date:** [March 16, 2022, 6:31pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/3 "2022-03-16T18:31:10Z")
Stingers are fire-and-forget guided munitions. The rocket is steered towards the target in the air and it will track the target as it maneuvers. ---
**Author:** ![griffin1977](https://avatars.discourse-cdn.com/v4/letter/g/977dab/32.png) [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Post date:** [March 16, 2022, 6:34pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/4 "2022-03-16T18:34:25Z")
> [@Omniscient](#): > > The rocket is steered towards the target in the air and it will track the target as it maneuvers. Yeah but it will track towards where the target _will be_ based on dead-reconing, not where it is now, surely? ---
**Author:** ![Omniscient](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omniscient/32/3290_2.png) [@Omniscient](https://boards.straightdope.com/u/Omniscient)\ **Post date:** [March 16, 2022, 6:35pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/5 "2022-03-16T18:35:58Z")
It’s a feedback system. It constantly steers towards where the target is at any instant. The software always points directly at the target, there’s no value to leading a target with this type of munition. It’s explicitly NOT dead-reckoning. It doesn’t attempt to predict anything. Doing so would make it incredibly vulnerable to evasive tactics. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [March 16, 2022, 6:41pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/6 "2022-03-16T18:41:13Z")
The FIM-92 ‘Stinger’ missile in the modern C variant uses both infrared and ultraviolet signals to guide the vehicle to the target. It is guided using [proportional navigation](https://epubs.siam.org/doi/pdf/10.1137/130947301) to update the trajectory and anticipate the target’s location, so in a sense it is ‘leading’ the target albeit not in the way a skeet shooter just shoots ahead of the target in confidence that a clay disk will not perform any kind of evasive maneuvers. The previous FIM-43 ‘Redeye’ did not have this capability and essentially had to be fired from the aft aspect of the target to hone in on the exhaust signature; if detected it was relatively easy for a maneuverable target to evade just by rapidly turning and diving, masking the infrared emissions. Stranger ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [March 16, 2022, 6:44pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/7 "2022-03-16T18:44:55Z")
> [@Stranger\_On\_A\_Train](#): > > in a sense it is ‘leading’ the target albeit not in the way a skeet shooter just shoots ahead of the target This answers my question. I have a tendency to write dissertations before asking questions, and I wanted to be brief. Obviously, simply leading a target like a duck hunter won’t work. It sounds like Stingers do ‘lead’ the target in the sense I was wondering about. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [March 16, 2022, 6:51pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/8 "2022-03-16T18:51:52Z")
I wouldn’t say it’s like a skeet shooter leading his target, it’s more like a linebacker taking a downfield angle to catch the ball carrier near the sideline. He’s going to take the angle, but he’ll adjust depending on what the ball carrier does- if he slows down, turns, etc… then the linebacker will also adjust. Stingers are _guided_ missiles- they are able to come up with a target track and take the angle, so to speak. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [March 16, 2022, 6:52pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/9 "2022-03-16T18:52:54Z")
It is using a quasi-predictive algorithm to anticipate where the target will be, so that is in essence ‘leading’ the target with incremental trajectory corrections. Modern efforts actually focus on navigation algorithms that will actually try to predict what maneuvers an evading target may make and reducing possible error, e.g. [Kalman filtering](https://www.kalmanfilter.net/default.aspx). You can find many papers on this in the [_AIAA Journal of Guidance, Control, and Dynamics_](https://arc.aiaa.org/journal/jgcd) as well as many applied mathematics publications like the _Society for Industrial and Applied Mathematics_ (which is where the link above is from) but they’re highly mathematical and often quite abstract in nature; making this work reliably in a real-world system is very complicated. Stranger ---
**Author:** ![Omniscient](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omniscient/32/3290_2.png) [@Omniscient](https://boards.straightdope.com/u/Omniscient)\ **Post date:** [April 18, 2022, 10:39pm UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/10 "2022-04-18T22:39:07Z")
> [@Stranger\_On\_A\_Train](#): > > algorithms that will actually try to predict what maneuvers an evading target may make and reducing possible error, e.g. [Kalman filtering](https://www.kalmanfilter.net/default.aspx) I feel like that website using that Einstein quote demonstrates a sibling of Gaudere’s Law. ---
**Author:** ![Snarky\_Kong](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Snarky\_Kong](https://boards.straightdope.com/u/Snarky_Kong)\ **Post date:** [April 19, 2022, 5:22am UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/11 "2022-04-19T05:22:59Z")
Is there a rule about confidently incorrectly answering a question in a thread and then just dropping it when corrected? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [April 19, 2022, 6:06am UTC](https://boards.straightdope.com/t/can-manpads-lead-a-target/961201/12 "2022-04-19T06:06:16Z")
> [@Stranger\_On\_A\_Train](#): > > It is guided using [proportional navigation](https://epubs.siam.org/doi/pdf/10.1137/130947301) to update the trajectory and anticipate the target’s location I was going to ask a question but I see that your linked paper answers it. The question was this: Anyone that has piloted a plane or boat knows a certain principle: if another object has a constant _angular_ position (i.e., it stays in a fixed spot on your windscreen), then you are on a collision course with it, regardless of your relative velocity (assuming it stays constant). Do any missiles use that principle? And, well, the answer is yes, and called proportional navigation. One of the very first things the paper states is: > Proposition 1.1 (constant bearing principle [8]). In a plane, two vehicles moving with constant velocities are on a collision course if and only if their line-of-sight does not rotate. It’s definitely a form of leading the target, since it is equivalent to aiming toward the collision point, not aiming toward the current position of the target.