Nav position fix?

I know this is a very basic question but how do you do a 'Navigation position fix'? I have looked in the manual to no avail (if it is there I can't find it).

Thanks.

Hey Latitude,

I don't have time to explain right now, so this is straight out of the extended English manual, page 13-34:

"CORRECTION Mode The correction mode is used to correct coordinate calculation error that are caused by inaccurate sensor information and computation. The following correction sub-modes are implemented:

 Fly-over correction

 Correction by locking a reference point with the I-251V

Fly-over and I-251V corrections are done in reference to up to four INU reference points. Each reference point is set in the mission editor and the coordinates are then input into the PNK. Correction is possible after pressing the “ОР” (Fix point – Update point) button on the PVI-800.

A fly-over correction is accomplished when the helicopter is over one of the four pre-programmed INU reference points, and when near the reference point, pressing the “ОР” (Fix point – Update point) button again on the PVI-800. Then, with the “И-251В - ПРОЛ” (I-251V Shkval – Fly over) switch in the “ПРОЛ” (Fly over) position, press the button with the number corresponding to the reference point on the PVI-800‟s keyboard. The number is then displayed on the PVI display. At the moment of reference point fly-over, press the “ЦУ” (Uncage Shkval –designate target) button on the cyclic and the current computed coordinates are updated with the correct coordinates of the reference point. The light on the “ОР” (Fix point – Update point) button will go off on the PVI-800 and the reference point number indication will extinguish. Correction mode using a lock by the I-251V is accomplished when within visual range of a reference point after setting the “И-251В - ПРОЛ” (I-251V Shkval – Fly over) switch to the “И-251В” position. When approaching a reference point, press the “ОР” (Fix point – Update point) button again and then enter the INU reference number on the PVI-800 keypad. Turn on the I-251V and slew the sensor‟s line of sight to the selected reference point. The “ИЗЛ – ОТКЛ” (Laser standby – Off) switch on the targeting mode control panel should be set to the “ИЗЛ” (Laser standby) position. Using the IT-23 TV indicator, place the tracking gate on the reference point and minimize its tracking gate to be smaller than the size of the reference point. Initiate an automatic track lock by pressing the “АВТ ЗАХВ” (Auto Lock) button on the collective. After the “ТА” (Tele-automatic lock) symbol is displayed, press the “ЦУ” (Uncage Shkval –designate target) button again on the cyclic. When this is done, the values of the range and the aiming angle (azimuth and elevation) of the reference point are loaded. With this data now known, the coordinates of the reference point are estimated and used to correct the helicopter‟s ownship coordinates. Press the “СБРОС” (Targeting mode reset) button on the targeting mode control panel to disable this mode."

Thanks miguez. It will take me sometime to digest this!

I also have problems with this, not the same problems as the original poster as I understand which buttons to press, however how do you identify WHERE to perform the fix, The ECRAN tells you thet you are near a fix point but as far as I can see the briefing notes in the included missions fail to show a picture of the bridge/lake/powerstation to let you know what feature to perform the fix over.

How do you decide where to fix in the included missions?

Cheers

Tom

Hi Tom,

I don't know about the included missions. When you build a mission, though, and add INU Fix Points, they show up in your ABRIS with the id "IFX**", or something similar, I can't recall exactely from memory, but the ** would be the number of the fix, starting with 01 and growing by one for every additional fix point.

If you have some time, build a test mission and add a couple of these to try it out. They can be added through the same section in the mission editor where you add navigational waypoints or weapons, it's the last button on the right, with four or five horizontal lines of decreasing length.

Fix points should be placed by a landmark for them to be used.

You will probly never need a INU fix point as the majorty of players arnt willing to fly far enough to need one. I have flowen over 150 klominters and had no problems with navagation error's.

Hey CAT,

I don't think ED built INU drift into BS, so technically, we'd never need it :). It is probably there for the realism factor.

yeah, I think it is a not yet implimented feature.

TBH, I'm hopeful they will put it in, as, well...geeky realism makes me fidgit less..

...and besides, INU is the primary nav tool of the AH64a (I believe?), so should make life pretty intereting with INU drift and no GPS backup once that bad-boy lands.

TBH, I'm hopeful they will put it in, as, well...geeky realism makes me fidgit less..

Amen, brother, amen :)

Hey CAT,

 

I don't think ED built INU drift into BS, so technically, we'd never need it :). It is probably there for the realism factor.

Actually you are wrong yes you do need to perform a Nav fix in the campaign it is necessary in those missions that are created with a low number of GPS sattelittes. Mission 2 in the Georgia campaign requires it.:smilewink:

But what about the differences between editor's and ABRIS' maps? Do not them render INU fix little acurate?

Actually you are wrong yes you do need to perform a Nav fix in the campaign it is necessary in those missions that are created with a low number of GPS sattelittes. Mission 2 in the Georgia campaign requires it.:smilewink:

Hey SUBS,

Thanks, and good point! Although, being prompted to do so does not mean an INU drift is simulated. Does anyone know for sure?

Yes it does drift checkout the review by BeachAV8R on SIMHQ he had to do an update in a mission and he mentions it was off.

Read this

http://www.simhq.com/_air11/air_347a.html

And then watch this video yes it does drift.

http://www.simhq.tv/downloads/_air_combat/black_shark/dcs_video2.zip

:smilewink:

Actually you are wrong yes you do need to perform a Nav fix in the campaign it is necessary in those missions that are created with a low number of GPS sattelittes. Mission 2 in the Georgia campaign requires it.:smilewink:

Interesting, however this brings up my earlier question. How do you determine what is the correct location to do the update? Unless the briefing screens show a picture of a particular terrain feature the only clue you get is a large blue dot on the ABRIS, which may or may not be in the correct position anyway (due to degraded GPS).

Cheers

Tom

Yes it does drift checkout the review by BeachAV8R on SIMHQ he had to do an update in a mission and he mentions it was off.

 

Read this

http://www.simhq.com/_air11/air_347a.html

And then watch this video yes it does drift.

http://www.simhq.tv/downloads/_air_combat/black_shark/dcs_video2.zip

:smilewink:

It was possibly enabled in the Beta, but I'm pretty sure INU drift is not currently in the game.

Infact, I'm pretty sure I've seen a post by evilbol or wags on this one.

You can still do INU corrections proceduraly, but the INU is 100% accurate al the time AFAIK so they are not necessary.

tried doing a search but couldn't find the post ... I remeber it was on the wish list for the patch....

Interesting, however this brings up my earlier question. How do you determine what is the correct location to do the update? Unless the briefing screens show a picture of a particular terrain feature the only clue you get is a large blue dot on the ABRIS, which may or may not be in the correct position anyway (due to degraded GPS).

 

Cheers

Tom

So , Generally IRL, INU fixes are done on known landmarks, and are pre-planned and well briefed to the pilot.

One famous example of INU updates on-the-fly was a long range night time apache attack that was guided in by Blackhawks or Pavelows (can't quite remember details), as they have a GPS

...when the attack group reached the IP, the Pavelows gave the apache pilots the lat/long from the GPS, and dropped a flare on the ground for the apache targetting system to use as a fix point.

This enabled the apaches to have accurate nav data to plan the attack as a group which otherwise would have been off by 10's of metrs in a random directon for each AH64a.

I forget whre I read this story, may have been in Ed Macy's book...

To answer your question though, the INU Fix point should be loaded into the ABRIS pre-flight, as well as beeing briefed (ie. check the map before flying to see what landmark the fix point is on!)..that way you can still fix even if the GPS is on the fritz.

Because there seems to be a co-ordinate problem between where you put the fix point in the ME, and where it appears on the ABRIS, I guess that's why they pulled the feature (for now)...again AFAIK.

If you check the above video it shows why he had to do the update due to the GPS going off his location because of a lack of sattelites and INS drift. You'll also see that the best location for an update is a bridge or some other landmark. IMO INS drift is probably still modeled but I'm unsure about the GPS inaccuracy that beach experiences in that video. Of course the INS update point must be in the briefing which unfortunately for the campaign missions is not in the breifing.:doh:

Does anyone know if they fixed the INU points. In 1.0 when placing a INU point on a bridge or other location in the ME then fly the mission and the INU point is way off (up to 50 meters) due to the difrint maps of the ME and game.

I don't know I need to check that one myself haven't done any updates myself I just ignore it when EKRAN tells me and fly VFR anyway.:D

One famous example of INU updates on-the-fly was a long range night time apache attack that was guided in by Blackhawks or Pavelows (can't quite remember details), as they have a GPS

...when the attack group reached the IP, the Pavelows gave the apache pilots the lat/long from the GPS, and dropped a flare on the ground for the apache targetting system to use as a fix point.

This enabled the apaches to have accurate nav data to plan the attack as a group which otherwise would have been off by 10's of metrs in a random directon for each AH64a.

 

I forget whre I read this story, may have been in Ed Macy's book..

This was the first Apache attack during Desert Storm back in 1991, when Apaches from the 101st Airborne Division performed a deep attack against Iraqi early warning radar sites. They were led to their IPs (initial points) by two USAF Pave Low helicopters. Pre-"block 51" Apaches did have an inertial unit, but it can't do navigation without the doppler navigation system. Over the terrain and distances covered (each Apache replaced a rocket pod with an external fuel tank), the doppler navigation system was expected to build up errors that were considered unsatisfactory for the mission. Note that GPS units were only just beginning to be installed on Apaches, so these Apaches did not have built-in GPS, although they may have had a few units that they could put on the dash.

At any rate, the Pave Lows certainly had superior navigation equipment, so the Apaches relied on them to lead them to the initial points for the attack, some 40 miles from the target areas. At the IPs, the Pave Low crews dropped chemlights, and the Apache crews updated their doppler navigation systems as they overflew the chemlights.

Note: When I said "block 51" I was referring to the "-51" software for the fire control computer (FCC). The -51 software includes a 5-channel GPS as well as ring laser gyro inertial unit for navigation. This is called the Embedded GPS Inertial (EGI) system. Unfortunately for us, ED has already stated that the version of the AH-64A that they hope to simulate is the "block 49a" version, meaning -49a FCC software, which does not include the EGI, although most AH-64As had an "add-on" GPS installed that didn't talk to any other system (like installing GPS in your car). It's also interesting to note that the AH-64A has no pretty map like the ABRIS provides in the Ka-50. The only visual representation you have in the AH-64A is the map you brought with you. Of course, plans change, so maybe we'll get lucky and get the -51 version if (when?) ED makes an AH-64A for DCS.

Well, I can positively say now that there is no INU drift (or it is neligible) after more than one hour an half of flight and one INU fixing. Same coordinates before and after.

Damn, AlphaOne Six, you are a goldmine! Always interesting to read your posts.

In my experience, there is no INU drift in the current sim and updating seems to make no difference. It is 100% accurate no matter how far you fly or what you do. I still perform updates just to increase the immersion, and I hope that INU drift is implemented in a patch.

INU drift still isn't implemented in DCS, yes/no?

It seems it is not yet implemented.