Racoon76 Posted June 21, 2020 Share Posted June 21, 2020 (edited) Hello, In fact i fired a 802AKG, when i receive the image my target was not in the AKG field of view. Of course i missedd my target. Back at the aerodrome, I noticed a 5 NM shift between my position and the coordinates of my INS position after 300 NM of navigation. This offset explains why the PP that I filled was also shifted by 5NM. So 2 questions: Is the INS position can drift ? What is the effect on the INS position when i switch the HNS to INS+GPS ? I assume that the GPS position is compared to the INS position and i guess if I select INS + GPS the INS position is corrected by using the GPS position (like in the real aircraft). Could you clarify this point please . Regards Edited June 21, 2020 by Racoon76 Link to comment Share on other sites More sharing options...
AeriaGloria Posted June 21, 2020 Share Posted June 21, 2020 Yea mine has been drifting a bit in HNS mode lately as well Black Shark Den Squadron Member: We are open to new recruits, click here to check us out or apply to join! https://blacksharkden.com Link to comment Share on other sites More sharing options...
Racoon76 Posted June 21, 2020 Author Share Posted June 21, 2020 OK. But i don't understand why I had so much drift. May be i did a mistake when i set my DST00, but a DST00 input error generally produces much larger offsets. So is INS+GPS set on the HNS can prevent this type of drift? Link to comment Share on other sites More sharing options...
paco2002 Posted June 21, 2020 Share Posted June 21, 2020 OK. But i don't understand why I had so much drift. May be i did a mistake when i set my DST00, but a DST00 input error generally produces much larger offsets. So is INS+GPS set on the HNS can prevent this type of drift? Yes, always use INS+GPS Link to comment Share on other sites More sharing options...
Tiger-II Posted June 21, 2020 Share Posted June 21, 2020 Hello, In fact i fired a 802AKG, when i receive the image my target was not in the AKG field of view. Of course i missedd my target. Back at the aerodrome, I noticed a 5 NM shift between my position and the coordinates of my INS position after 300 NM of navigation. This offset explains why the PP that I filled was also shifted by 5NM. So 2 questions: Is the INS position can drift ? What is the effect on the INS position when i switch the HNS to INS+GPS ? I assume that the GPS position is compared to the INS position and i guess if I select INS + GPS the INS position is corrected by using the GPS position (like in the real aircraft). Could you clarify this point please . Regards Correct. Motorola 68000 | 1 Mb | Debug port "When performing a forced landing, fly the aircraft as far into the crash as possible." - Bob Hoover. The JF-17 is not better than the F-16; it's different. It's how you fly that counts. "An average aircraft with a skilled pilot, will out-perform the superior aircraft with an average pilot." Link to comment Share on other sites More sharing options...
Tiger-II Posted June 21, 2020 Share Posted June 21, 2020 OK. But i don't understand why I had so much drift. May be i did a mistake when i set my DST00, but a DST00 input error generally produces much larger offsets. So is INS+GPS set on the HNS can prevent this type of drift? I'm not sure why it drifts so quickly. Without GPS (or in fact, and position correction), ALL INS systems will drift. This is unavoidable. The drift rate seems quite high, but FAST ALIGN is intended to get you flying quickly (e.g. intercept approaching enemy aircraft). If you want the best alignment, use GC. It will perform a 4 minute alignment, and should have the highest system accuracy. Also, are you flying on a map OTHER than Caucus? I've found that PG map can cause all manner of INS and attitude problems, but these should be fixed in the latest update. A couple of updates ago I had major position error in PG despite precision alignment. Should be fixed now. Motorola 68000 | 1 Mb | Debug port "When performing a forced landing, fly the aircraft as far into the crash as possible." - Bob Hoover. The JF-17 is not better than the F-16; it's different. It's how you fly that counts. "An average aircraft with a skilled pilot, will out-perform the superior aircraft with an average pilot." Link to comment Share on other sites More sharing options...
J20Stronk Posted June 21, 2020 Share Posted June 21, 2020 I'm not sure why it drifts so quickly. Without GPS (or in fact, and position correction), ALL INS systems will drift. This is unavoidable. The drift rate seems quite high, but FAST ALIGN is intended to get you flying quickly (e.g. intercept approaching enemy aircraft). If you want the best alignment, use GC. It will perform a 4 minute alignment, and should have the highest system accuracy. Also, are you flying on a map OTHER than Caucus? I've found that PG map can cause all manner of INS and attitude problems, but these should be fixed in the latest update. A couple of updates ago I had major position error in PG despite precision alignment. Should be fixed now. Thing is though, even with GC alignment and HNS on, drift will begin to occur even as you taxi out to the runway. I've tested by spawning a jet already on the runway and swithing to the airport WPT. Doing gentle left end right turns on the tarmac is enough to misalign the INS, I even managed to get a couple hundred meters of drift by doing nothing except swerving the plane around on the runway. HNS didn't help restore the drift, so that is definitelynot working correctly. and switching to AG gave the actual correct position of the WPT which is incorrect (it should give me the "drifted" position instead) The Navigation systems are broken, it drifts WAY too quickly with even the gentlest of maneuver and HNS doesn't help restore the drift or at least slow it down. This issues havebeen reported before but have never been fixed. Link to comment Share on other sites More sharing options...
Tiger-II Posted June 21, 2020 Share Posted June 21, 2020 Old-school strap-down systems drift at around 0.6 NM/hr without updates, and I assume the Jeff is using RLG which drift far less (typically 0.1 NM/hr or less). GPS input should keep it accurate pretty much all the time. I think the TVV being above the horizon line after alignment is a symptom of a wider problem. I'd expect them to be aligned. Motorola 68000 | 1 Mb | Debug port "When performing a forced landing, fly the aircraft as far into the crash as possible." - Bob Hoover. The JF-17 is not better than the F-16; it's different. It's how you fly that counts. "An average aircraft with a skilled pilot, will out-perform the superior aircraft with an average pilot." Link to comment Share on other sites More sharing options...
Racoon76 Posted June 21, 2020 Author Share Posted June 21, 2020 The drift is 15°/h max on an East/West heading due to the rotation of the earth (360/24 = 15). We cannot therefore take into account a drift in NM but in degrees because it will necessarily depend on our lattitude. Besides, since the PG map is further south, the angular drift will necessarily be greater than Caucasus. Link to comment Share on other sites More sharing options...
Hoffster Posted June 21, 2020 Share Posted June 21, 2020 https://forums.eagle.ru/showthread.php?t=275428 post #3 Link to comment Share on other sites More sharing options...
Tiger-II Posted June 21, 2020 Share Posted June 21, 2020 https://forums.eagle.ru/showthread.php?t=275428 post #3 Very cool! Motorola 68000 | 1 Mb | Debug port "When performing a forced landing, fly the aircraft as far into the crash as possible." - Bob Hoover. The JF-17 is not better than the F-16; it's different. It's how you fly that counts. "An average aircraft with a skilled pilot, will out-perform the superior aircraft with an average pilot." Link to comment Share on other sites More sharing options...
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