Some questions about laser rangefinder

[sweinhart3]

Im working on chapter 1 of oil war campaign and the last 2 missions I flew recently mine burned out after 1.5 loads of armament. I use rangefinder once per enemy unit followed by either a vihker attack or guns/rockets. In total Ive been getting roughly 30 cycles (excluding beam riding cycles) between burnouts. I simply cannot get target ranging afterward and weapons are useless outside of gun site mode.

Edited February 4, 2010 by sweinhart3

[Bucic]

GOOD FIND!!! What page is this on?

 

For your second question, it's pretty easy and you were so close!

 

 

1. Laser OFF
   
2. Lock Target "TA"
   
3. Laser STNDBY
   
4. Shoot Vikhr
   

You get a laser rangefinder shoot normally every time you press the lock button so yes, you get a new rangefinder shoot on the second target.

So the above sorts out that you put laser on STNDBY only when you need it. What about the Laser Rest button? When should I use it? Reading this topic I recalled that I did a lot of Shkval searching and then I could launch anything. I had my Laser on STNDBY from take off. So it is obvious that I burned it.

[Frederf]

Nonsense. Laser on STNDBY for the whole flight is perfectly fine. It's what I do. The only reason to fiddle with it is you are super paranoid about EMCON or otherwise want to trigger optical "TA" tracks without using the rangefinder.

 

Whether or not your laser has burned is not obvious just because you couldn't launch a missile. There are a lot of other reasons why you couldn't. The best test is to see if you can get a range with the rangefinder. No numbers, no laser.

 

 

Laser Reset button (FM 6-20) is tied to the laser designator purpose (the 3rd purpose apart from rangefinding and Vikhr guidance grid projection). It's for manually ceasing laser designation instead of the auto-time out feature.

[Bucic]

But I quoted your own words :) Should I note that the first step was... obsolete?

[Frederf]

Second question:

I tried to find a way to by-pass the rangemeasuring.

 

- I searching for enemys with the shkval, laser is OFF.

- I found a enemy and adjust the target-box at the enemy

- I switched the laser to STANDBY and locked the target (TA)

-> Laser is active for -?- time to do the rangemeasuring, countdown will be displayed

- After the countdown I shoot the Vikhr.

-> Laser is active for time till impact plus 6 seconds.

- Directly after impact I unlock the old target, moving the target-box to the next taget and lock it (TA) within this 6 seconds the laser is still active.

 

Is there a rangemeasuring too for the second target????

 

I was replying to this question. The procedure I mentioned is how to accomplish a Vikhr shoot without rangefinding, not that this procedure is normal (at least for me).

[Bucic]

OK, but for terrain scanning Laser OFF is desirable. At least I use the Lock a lot hence the rangefinding happens often. I couldn't get the range either in the situation I described earlier.

 

Why I use Lock (ENTER) during terrain scanning:

1. Shkval cursor without laser range is terribly off compared to the ABRIS map. It jumps to the right place after range finding.

2. Sometimes after a lock on moving ground target Shkval keeps moving in the same direction the locked target was going and locking the ground is the only way I know to stop it.

 

Is there any solution to any of these two cases?

[zdXu]

1. Shkval cursor without laser range is terribly off compared to the ABRIS map. It jumps to the right place after range finding.

No active laser = no range measurement = Shkval terribly off IN RANGE (but not in heading). Logical. No workaround i know of.

(The other day i have read about someone hold the target-lock-button more than 3 seconds (or something like that) and then the HUD-range is displayed (and the exact range on the ABRIS-map is shown) also when you switch the laser afterwards in range-finding-mode-off. But i dont know further details).

 

Sometimes after a lock on moving ground target Shkval keeps moving in the same direction the locked target was going and locking the ground is the only way I know to stop it.

This is a desired feature of the Ka50-software, which calculate the path of moving objects even when they are behind obstacles.

If you want to get rid of a shkval-problem (and dont want to use it for another targeting/measurement) then shut off the shkval or switch it to shkval-standby-mode(?).

Edited April 25, 2010 by zdXu

[Frederf]

The answer to #1 is not to expect the ABRIS Shkval indication to be anything better than angular (line out to infinity) before ranging. The display can't possibly know the relative position of the Shkval line-of-sight endpoint until it has all Theta, Phi, and R values.

 

The ground stabilization point can't possibly be more than a vague mathematical guess without a distance if you think about it. I forget how the Shkval even attempts a ground (or "grid") stabilization without range information, but there's a lot of math approximations in it like aircraft is level, Earth is a flat plane, altitude is altitude above point. Stuff like that.

 

#2, angular rates mode (shows the upside-down U or "staple" character) is a feature and I think just a bump to the Shkval control hat should undo it. That or wait for the rates mode to time out which isn't terribly long.

 

OK, but for terrain scanning Laser OFF is desirable.

 

I don't understand this statement. What activity is "terrain scanning"? When I fly I turn laser to standby, fly the mission, turn laser off. I've never seen a benefit to laser off.

[Bucic]

No active laser = no range measurement = Shkval terribly off IN RANGE (but not in heading). Logical. No workaround i know of.

(The other day i have read about someone hold the target-lock-button more than 3 seconds (or something like that) and then the HUD-range is displayed (and the exact range on the ABRIS-map is shown) also when you switch the laser afterwards in range-finding-mode-off. But i dont know further details).

 

 

This is a desired feature of the Ka50-software, which calculate the path of moving objects even when they are behind obstacles.

If you want to get rid of a shkval-problem (and dont want to use it for another targeting/measurement) then shut off the shkval or switch it to shkval-standby-mode(?).

 

Will try the first one one day. The second part is not a solution, sorry. It's like restarting system to clear the clipboard.

 

 

 

The answer to #1 is not to expect the ABRIS Shkval indication to be anything better than angular (line out to infinity) before ranging. The display can't possibly know the relative position of the Shkval line-of-sight endpoint until it has all Theta, Phi, and R values.

 

The ground stabilization point can't possibly be more than a vague mathematical guess without a distance if you think about it. I forget how the Shkval even attempts a ground (or "grid") stabilization without range information, but there's a lot of math approximations in it like aircraft is level, Earth is a flat plane, altitude is altitude above point. Stuff like that.

 

I'm not that interested in under the hood stuff. Rather if there is a solution to the problem or not :)

 

 

#2, angular rates mode (shows the upside-down U or "staple" character) is a feature and I think just a bump to the Shkval control hat should undo it. That or wait for the rates mode to time out which isn't terribly long.

 

I don't consider waiting a solution because I remember fighting this "feature" for far too long and only locking with RF on let me get rid of it. When I'm in a workload crippled helicopter on a perfect attack position equipped with rather outdated non-Fire-and-Forget missiles there's no time to play arcade games on the Shkval. I need control.

 

 

I don't understand this statement. What activity is "terrain scanning"? When I fly I turn laser to standby, fly the mission, turn laser off. I've never seen a benefit to laser off.

With RF OFF you don't get even rough estimates on ABRIS on where's the Shkval pointing at. To get it you need to press LOCK. When RF is on STNDBY you waste a RF cycle every time you press LOCK.

 

Edit:

correction. You do when you slew it. But still there are situations where I may need a Shkval LOCK without wasting RF cycle.

 

RF - Laser Range Finder obviously ;)

[Frederf]

Let's see if I can clean up my terminology to be more exactly matching that used in the Flight Manual. It's rather confusing if we don't use exactly the same words for the exact same features. I'll put them in bold.

 

OK, but for terrain scanning Laser OFF is desirable. At least I use the Lock a lot hence the rangefinding happens often. I couldn't get the range either in the situation I described earlier.

 

I still don't really know what you mean by "terrain scanning." If pressing lock while Shkval pointed at a solid object and don't get a range then either the laser is inhibited (off) or it is broken.

 

The memory mode has really never been any bit of a problem with me. In fact it's extremely rare that I even enact it. The target has to do something strange like disappear behind a hill/building for it to happen. It doesn't run for very long (3 seconds max) and doesn't really take the cursor position too far away. Either way, it's a built-in, can't-help-it feature of the optical tracking routine.

 

Either way, I believe memory mode and tracking mode both require a press of the lock to slew the Shkval line of sight manually away from the target. This is to prevent accidentally canceling tracking or memory mode.

 

I have this feeling that you're not experiencing problems with memory mode (“П” cue) but rather with the ground stabilized mode (“ТГ” cue). GS mode is one of the modes where the cursor can go rather annoying haywire quick drastically and quickly if the updating calculations are from poor data assumptions. If the Shkval ground stabilized point solution starts to get hairy, you might be fastest to reset and start again. Not liking it doesn't really change the fact.

 

One should separate angular tracking (cue "TД") which is purely an optical image-processing from laser rangefinding which is a laser process. They are both commanded by the lock button but are quite distinct. You can get tracking without range and range without tracking.

 

I don't believe that the length of the press of the collective "lock" button does any different behavior of the Shkval/laser function outside of cannon use when not in tracking mode.

 

As for the ABRIS "Shkval Pole," you have to appreciate the under the hood stuff or accept the behavior at face value. Appreciate that the ABRIS display of the Shkval line of sight is in essence a complex math problem that is only as effective (and complete) as the information the PrPNK is given. It ain't supposed to give an accurate pole until it has accurate information. The Shkval "pole" is in angles-only mode initially and then in angle-and-length mode when given a range. The "fix" is to alter expectations.

 

When not even in ground stabilization mode, the system can hardly be expect to keep up with non-stabilized Shkval aiming display. The line would be all over the ABRIS screen (which was added long after the IT-23 was designed) anyway.

 

To get it you need to press LOCK. When RF is on STNDBY you waste a RF cycle every time you press LOCK.

 

Hardly a waste. Laser will work for a long, long time as long as it's not abused. Also you can get a tracking optical "lock" without the laser at all.

[SFJackBauer]

By testing inside the simulator I find you can get reasonably accurate tracks in ABRIS without using the laser. My guess would be the INU provides the calculation for it. However no number on Shkval, you need to guess the range using the map.

[Bucic]

Let's see if I can clean up my terminology to be more exactly matching that used in the Flight Manual. It's rather confusing if we don't use exactly the same words for the exact same features. I'll put them in bold.

 

Thank you. I'm sorry I didn't follow this guideline myself before. Loose terminology era ended with the release of DCS.

I still don't really know what you mean by "terrain scanning." If pressing lock while Shkval pointed at a solid object and don't get a range then either the laser is inhibited (off) or it is broken.

Let's lose the "terrain scanning". From now on I'll call it manually searching for targets so it will become self explanatory. Just searching for targets using Shkval.

 

The memory mode has really never been any bit of a problem with me. In fact it's extremely rare that I even enact it. The target has to do something strange like disappear behind a hill/building for it to happen. It doesn't run for very long (3 seconds max) and doesn't really take the cursor position too far away. Either way, it's a built-in, can't-help-it feature of the optical tracking routine.

I remember the tracking gate wandering to the side for much longer than 3 s so I guess I just disable the ground stabilization "ТГ" (BTW, for the first time I noticed that this are actually two letters - T and G, not some artistic symbol.

 

As for the can't-help-it feature of the memory mode “П” - noted, thanks.

 

I have this feeling that you're not experiencing problems with memory mode (“П” cue) but rather with the ground stabilized mode (“ТГ” cue). GS mode is one of the modes where the cursor can go rather annoying haywire quick drastically and quickly if the updating calculations are from poor data assumptions. If the Shkval ground stabilized point solution starts to get hairy, you might be fastest to reset and start again. Not liking it doesn't really change the fact.

Exactly like I said few lines before. Good guess based on my vague hints :)

 

I don't believe that the length of the press of the collective "lock" button does any different behavior of the Shkval/laser function outside of cannon use when not in tracking mode.

I vaguely recall that it did make a difference in some cannon/rockets-Laser rangefinder combined mode. I can't confirm it though.

 

As for the ABRIS "Shkval Pole," you have to appreciate the under the hood stuff or accept the behavior at face value. Appreciate that the ABRIS display of the Shkval line of sight is in essence a complex math problem that is only as effective (and complete) as the information the PrPNK is given. It ain't supposed to give an accurate pole until it has accurate information. The Shkval "pole" is in angles-only mode initially and then in angle-and-length mode when given a range. The "fix" is to alter expectations.

 

When not even in ground stabilization mode, the system can hardly be expect to keep up with non-stabilized Shkval aiming display. The line would be all over the ABRIS screen (which was added long after the IT-23 was designed) anyway.

It should be no problem for Ka-50 avionics to calculate where the Shkval LOS points on the terrain. I could calculate this on a piece of paper. This is valid for flat terrain, on higher negative values of Shkval elevation angle and I believe it can be confirmed in-game. What you're saying is valid for non-flat terrain, which is the case most of the time.

 

Hardly a waste. Laser will work for a long, long time as long as it's not abused. Also you can get a tracking optical "lock" without the laser at all.

I were manually searching for targets while hovering at low alt hence at low Shkval elevation and I were pressing the lock every 3 or so seconds. But lets leave such vague cases. Lets focus on my experiences from this year :)

 

Thank you for your help!

 

I see now that bolding any official terms should be obligatory on the DCS forums. Ctrl+B and Ctrl+I keyboard shortcuts work just like in most office suites . It makes reading so much easier. Even my own posts.

Edited April 26, 2010 by Bucic

[Frederf]

It's pretty easy for the Shkval (well the PrPNK) to determine the Shkval point of interest provided provided it has a valid range. Without a range value, it's nearly impossible. The best point imaginable without range data would be where the Shkval LOS intersects some imaginary flat plane at the baro altitude below the helicopter. I don't even know if the system responsible for the Shkval ground stabilization mode has access to altimeter data.

 

not some artistic symbol

 

Yeah, most of the cues are Cyrillic letters. It might be nice for the forum to add the common "TA" and ground stabilization cues as smilies so we could have clearer communications.

 

Personally my habits are starting to rely more on the HMS, DL, and NAVTGT points for closer initial Shkval positionings and less slew work. I sort of keep the number of my ground stabilization and lock button presses down but not to a huge extent. I use the rangefinder pretty freely but not excessively and it's rare when it lets me down. Almost always laser failure is associated with a mission with a rearm and I avoid those as best I can.

 

A pleasure working with you. DCS is great because no matter how much you know, there's still much to learn!

[Yurgon]

I did some reading up on the laser range finder and came across this thread which helped me a lot.

 

I believe there is one unanswered question I just happened to find the answer to.

 

I don't believe that the length of the press of the collective "lock" button does any different behavior of the Shkval/laser function outside of cannon use when not in tracking mode.

 

I vaguely recall that it did make a difference in some cannon/rockets-Laser rangefinder combined mode. I can't confirm it though.

My dcs-bs_flight_manual_eng.pdf that came with 1.0.2 contains the following paragraph in the section The I-251 “Shkval” Electro-Optical Targeting System (4-12):

 

If the “АС-ПМ” (Auto-Tracking – Gun sight) switch [P] on the Targeting Mode Control Panel is set to “АС” (Auto-Tracking) and the “ППУ” (Moving canon – automatic weapons mode) mode is selected, the laser range-finder is activated with the first depression of the “АВТ ЗАХВ” (Lock) button and remains active for three seconds. The laser range-finder also activates when Auto-Tracking mode is entered and will fire from three or eight seconds, depending on the range and closure rate to the target. If the “АС-ПМ” (Auto-Tracking – Gun sight) switch is set to “ПМ” (Gun sight), the laser is activated with every depression of the “АВТ ЗАХВ” (Lock) button and remains active until the button is released. After this, the “ПАУЗА” (Pause) cue is displayed on the HUD, as well as the time remaining until another laser firing is possible. Laser firing is prevented when in „PAUSE” mode and the „PAUSE” time is generally equal to the time of the last firing.