159th_Viper Posted February 2, 2012 Posted February 2, 2012 Bottom-line: Approximately a 30 foot CEP if I recall. Novice or Veteran looking for an alternative MP career? Click me to commence your Journey of Pillage and Plunder! [sIGPIC][/sIGPIC] '....And when I get to Heaven, to St Peter I will tell.... One more Soldier reporting Sir, I've served my time in Hell......'
sobek Posted February 2, 2012 Posted February 2, 2012 Might the JDAM have a "GPS disabled" mode so that, if the constellation of GPS satellites was jammed or destroyed, it could still be used? The INS works as a "fail safe" for the GPS if the signal is lost, AFAIK. Good, fast, cheap. Choose any two. Come let's eat grandpa! Use punctuation, save lives!
Speed Posted February 2, 2012 Posted February 2, 2012 The INS works as a "fail safe" for the GPS if the signal is lost, AFAIK. MMmm... but GPS isn't going to give you attitude information, it's just going to give you position and velocity. That's not enough to guide a bomb, the bomb has to know what its attitude is so it can know which control surfaces it needs to move. The JDAM's INS has gotta be used to supply that information, right? Intelligent discourse can only begin with the honest admission of your own fallibility. Member of the Virtual Tactical Air Group: http://vtacticalairgroup.com/ Lua scripts and mods: MIssion Scripting Tools (Mist): http://forums.eagle.ru/showthread.php?t=98616 Slmod version 7.0 for DCS: World: http://forums.eagle.ru/showthread.php?t=80979 Now includes remote server administration tools for kicking, banning, loading missions, etc.
BlueRidgeDx Posted February 2, 2012 Posted February 2, 2012 You're right, Speed. JDAM GPS corrects for INU drift. WCMDs have no GPS correction, hence a higher CEP. Both weapons are indeed navigating to point in space defined by a set of coordinates, and an elevation. Both weapons derive their present position using the aircraft's EGI (or equivalent system). WCMDs can be dropped as a conventional CBU without INU guidance, but JDAM can't. By nature of its design, if a JDAM lost it's GPS signal during guidance, it would continue to guide via INU only. "They've got us surrounded again - those poor bastards!" - Lt. Col. Creighton Abrams
Speed Posted February 2, 2012 Posted February 2, 2012 WCMDs can be dropped as a conventional CBU without INU guidance, but JDAM can't. By nature of its design, if a JDAM lost it's GPS signal during guidance, it would continue to guide via INU only. My question is, if you don't trust GPS anymore or if it is lost entirely, could you tell the JDAM to disable its GPS receiver? Maybe it's classified, but it seems like a reasonable capability to have. Intelligent discourse can only begin with the honest admission of your own fallibility. Member of the Virtual Tactical Air Group: http://vtacticalairgroup.com/ Lua scripts and mods: MIssion Scripting Tools (Mist): http://forums.eagle.ru/showthread.php?t=98616 Slmod version 7.0 for DCS: World: http://forums.eagle.ru/showthread.php?t=80979 Now includes remote server administration tools for kicking, banning, loading missions, etc.
BlueRidgeDx Posted February 2, 2012 Posted February 2, 2012 (edited) I don't think the answer to that can be found in a public source. Edit: I lied. There are actually a few online sources that disclose the capability to deselect GPS updating. Here's one: http://www.fas.org/man/dod-101/sys/smart/jdam.htm Edited February 2, 2012 by BlueRidgeDx "They've got us surrounded again - those poor bastards!" - Lt. Col. Creighton Abrams
Waxi Posted February 2, 2012 Author Posted February 2, 2012 Just be careful with the wind...the mission editor displays wind direction TO, while the CDU displays wind FROM. If you enter the same values into the CDU that you entered into the ME, everything will be off by 180 degrees. I was entering the wind data into the CDU as given on the mission briefing screen. Do I have to invert the wind directions indicated at the briefing screen as well or can I enter them into the CDU as they are given?
BlueRidgeDx Posted February 2, 2012 Posted February 2, 2012 Reverse it. "They've got us surrounded again - those poor bastards!" - Lt. Col. Creighton Abrams
Waxi Posted February 2, 2012 Author Posted February 2, 2012 I performed several tests and it seems that independent of what I enter into the CDU WIND page, the bomblets on the parachutes always drift away significantly with the wind. Interestingly, the wind data entered into the mission editor is the same as shown at the briefing screen but is different from what the CDU shows in the mission. However, neither data (the plain and reversed wind data from the mission editor and the briefing screen nor the data shown by the CDU) brings the bomblets closer to the targets. I was successful in manually compensating for the wind by setting the SOI for a CCRP release off the (stationary) target against the direction of the wind. However, since I estimated the required offset empirically (i.e., by dropping a "test bomb" and observing where it opens), this seems not to be practical.
lubey Posted February 3, 2012 Posted February 3, 2012 Yeah I agree, I think the WCMDs and the CDU wind page only help guide the bomb/ predict the correct release point respectively in order to hit the SPI, they don't take into account the drift after the bomblets disperse... SPECS: Intel Core i5 760 @ 3.2 Ghz +turboboost enabled, 12 GB DDR3 1600 @ 1500 Mhz, ATI Radeon 5850, TrackIR 5, X52 Pro and Saitek pedals
159th_Viper Posted February 3, 2012 Posted February 3, 2012 Be sure to set your HOF lower to minimise drift. Novice or Veteran looking for an alternative MP career? Click me to commence your Journey of Pillage and Plunder! [sIGPIC][/sIGPIC] '....And when I get to Heaven, to St Peter I will tell.... One more Soldier reporting Sir, I've served my time in Hell......'
sobek Posted February 3, 2012 Posted February 3, 2012 The JDAM's INS has gotta be used to supply that information, right? Yes, i didn't mean to imply otherwise. I was just talking about the case of GPS failing. Good, fast, cheap. Choose any two. Come let's eat grandpa! Use punctuation, save lives!
Tailgate Posted February 3, 2012 Posted February 3, 2012 I never thought that CCRP would work on moving targets, but I loaded up some CBU-105's, tracked the tank column in TGP and set a SPI. Dropped them from 12k and it took out a large part of the column. In the original scenario I described, the tank column was only moving at 10 kts, so even from 12,000 ft they were still within the dispersal range during impact. To test it, I bumped up their speed to 20 kts, tracked a tank in the middle of the column, released from 12k and followed the bombs down. It impacted at the last point tracked prior to release which well behind the vehicles. So it appears that the CBU's are performing correctly in CCRP mode and do not magically track moving targets.
Ghanja Posted February 9, 2012 Posted February 9, 2012 Regarding the wind direction I asked the support about it and gave this example: Example: - wind direction in briefing and mission editor is 090 - so do I have to enter 270 in the CDU? The answer was: No, you don't. [sIGPIC][/sIGPIC] .:: My System ::. .:: My Paintings ::.
Depth Posted February 9, 2012 Posted February 9, 2012 Yeah I agree, I think the WCMDs and the CDU wind page only help guide the bomb/ predict the correct release point respectively in order to hit the SPI, they don't take into account the drift after the bomblets disperse... Wind corrections in the CDU are more useful for unguided bombs. [sIGPIC][/sIGPIC]
BlueRidgeDx Posted February 9, 2012 Posted February 9, 2012 Regarding the wind direction I asked the support about it and gave this example: Example: - wind direction in briefing and mission editor is 090 - so do I have to enter 270 in the CDU? The answer was: No, you don't. Unless the CDU is coded incorrectly, then yes, you do. The CDU winds are entered as a direction FROM, as are all winds in every facet of aviation. The Mission Editor winds are entered as a direction TO, unlike anything in aviation. If you want to use the ME winds in the CDU, you MUST switch them. "They've got us surrounded again - those poor bastards!" - Lt. Col. Creighton Abrams
Ghanja Posted February 10, 2012 Posted February 10, 2012 I know. Both, the ME and also the briefing give you "blowing TO" and the CDU needs to have "blowing FROM". So actually I do have to reverse my entry (as mentioned in my example). But now the support tells me, that I don't have to reverse and now you tell me I have to to reverse. I am totally confused now - is the CDU screwed up? [sIGPIC][/sIGPIC] .:: My System ::. .:: My Paintings ::.
PhoenixBvo Posted February 13, 2012 Posted February 13, 2012 I know. Both, the ME and also the briefing give you "blowing TO" and the CDU needs to have "blowing FROM". So actually I do have to reverse my entry (as mentioned in my example). But now the support tells me, that I don't have to reverse and now you tell me I have to to reverse. I am totally confused now - is the CDU screwed up? No need for confusion: What you write there is correct. The ME uses the reverse convention from the aviation point of view. Probably the guy programming it had more of a physics background where vector fields have arrows pointing in the direction of flow. Aviation uses the meteorology mindset, which probably inherited the "blowing FROM" convention from sailing, where people have always been interested in where the wind comes from. Who cares where it goes after it passes your ship? :D [sIGPIC][/sIGPIC] CPU i7 4970k @ 4.7 GHz RAM 16GB G.Skill TridentX 1600 ATX ASUS Z97-PRO DSU Samsung 850 PRO 256GB SSD for Win10, Plextor M6e 128GB SSD for DCS exclusively, RAID-1 HDDs GFX Aorus GTX 1080 Ti 11GB Xtreme Edition, ASUS ROG Swift PG279Q, 27" with G-Sync, Oculus Rift CV1 HID TM HOTAS Warthog + 10 cm extension, MFG Crosswind pedals, TrackIR 5, Obutto oZone My TM Warthog Profile + Chart, F-15C EM Diagram Generator
Ghanja Posted February 13, 2012 Posted February 13, 2012 So to close this one down: Wind direction in briefing 090 means I have to enter 270 in the CDU? [sIGPIC][/sIGPIC] .:: My System ::. .:: My Paintings ::.
Jona33 Posted February 13, 2012 Posted February 13, 2012 So to close this one down: Wind direction in briefing 090 means I have to enter 270 in the CDU? Yes. Always remember. I don't have a clue what I'm doing
Ghanja Posted February 13, 2012 Posted February 13, 2012 Thx and Amen ... :thumbup: [sIGPIC][/sIGPIC] .:: My System ::. .:: My Paintings ::.
WildBillKelsoe Posted August 6, 2013 Posted August 6, 2013 What is the most effective way of taking out a moving column of MBTs, such as in the first missions of the Devil's Cross campaign? Any suggestions are welcome. I was trying to lead aim CBU-97s with CCIP but the tanks were moving too fast and always got out of the area covered by the bomb. I guess this is due to the bomblets being retarded by parachutes and that I just have to increase the lead aim. What do you think? Another approach could be hitting one of the tanks with a Maverick, which in the sim always causes the whole column to stop and spread making it an easier target for the CBU-97s. However, this may not be a valid tactic in the real world. What do you think? take the most forward tank in the column as target, and zoom out to see the length of the column from that tank with TGP. Next, set a CCIP solution at 8,000 min alt and 10 sec TOF and pickle by leading with the length of the column worth. For example if the tank number 1 to tank number 10 magnifies to 24X on TGP, you set the release point to be parallel and equal to tank 1 + 24X magnification. Speed is important as above 20 kts, on a curved road, the pK is lowered as opposed to 20kts speed and a straight road. Pick the most straight road or engage the first tank to spread them and work your way from there into the clusters scattering. AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.
Hamblue Posted August 7, 2013 Posted August 7, 2013 You do realize the thread has been dead for a year and a half? :music_whistling: Asus Sabertooth P67 Motherboard 2600k CPU, 16 gig DDR3, 1600. Samsung 830, 256 gig hard drive, GTX780 Video Card, Warthog Hotas, Razer Mamba mouse. Saitek Combat Rudder Pedals. Trackir 5, Verizon FIOS 25Meg Up/Down
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