Maverick questions, TDC without TGP

[PicklePicklePickle]

Hello,

 

I gave up on using the TGP with the mavericks, since they seem to work fine without it. Carrying 6 is pretty useful. I set A-G, push back on TMS to lock the TDC to the flight path indicator, slew near target, TMS forward and then use the ground stabilized maverick to lock and fire.

 

However, I have 2 questions:

 

Is there a way to do a rapid follow-up maverick without having to re-do the entire process above? I find my self firing and then relocking the TDC to the flight path, and starting again. Some of these targets are near each other so if I could just have the next maverick aiming at the TDC, that would be much better...the TDC appears to stay on the spot on the ground after I fire, which brings me to my next question....

 

I have some confusion on what the TDC represents. Even without the TGP equipped on the plane, I can slew the TDC and then ground stabilize it...however when I SOI the maverick there is the HUD circle(separate from TDC) which is aiming at a slightly different place representing the Maverick seeker head....so what exactly is the TDC? Is it a sensor on the F-16 without the TGP? It seems to be aiming at a different place than the maverick.

 

I'm wondering if the TDC shouldn't be there without the TGP loaded, and this is just the current state of early access...

 

Thanks in advance!

Edited March 14, 2021 by PicklePicklePickle

[Machalot]

You need to perform the Boresight procedure to align the Mavericks with the TGP.

 

[PicklePicklePickle]

Thanks, but i'm aware about that procedure if I have the TGP on the plane.  I'm talking about the case where I don't have a TGP on the plane, just the mavericks. The TDC still points to a different location and there is no TGP.

 

[bart]

9 minutes ago, PicklePicklePickle said:

Thanks, but i'm aware about that procedure if I have the TGP on the plane.  I'm talking about the case where I don't have a TGP on the plane, just the mavericks. The TDC still points to a different location and there is no TGP.

 

 

OP raises a good point here. I too would like to see folks input on this issue.

 

It doesn't make sense to have to boresight a Maverick to the TDC cue on the HUD, and even if we had to is there an accurate procedure of doing this without using any kind of optics as we have with the TGP? Surely the Mav should follow the TDC cue accurately?

Edited March 14, 2021 by bart

[Machalot]

6 hours ago, PicklePicklePickle said:

Thanks, but i'm aware about that procedure if I have the TGP on the plane.  I'm talking about the case where I don't have a TGP on the plane, just the mavericks. The TDC still points to a different location and there is no TGP.

 

Ah, sorry, I skimmed the end of your post and missed that. 

[Furiz]

14 hours ago, bart said:

 

OP raises a good point here. I too would like to see folks input on this issue.

 

It doesn't make sense to have to boresight a Maverick to the TDC cue on the HUD

 

 

It does make sense to boresight the Mav, how else will the system on the plane know where Mav is looking? Cue on the HUD is just a projection of what the system of the plane thinks where the Mav is looking.

It needs to be calibrated, same as you need Align your Nav so you can see contacts on the HSD, if you don't align your Nav the system doesn't know where you are therefore it can't show proper contact positions.

[Bunny Clark]

Sounds like you're using the Mav in the VIS delivery mode. 

 

In the VIS mode, you initially steer the seeker using the TD Box on the HUD. This will begin caged to the flight path marker, but can be slewed off of it with the Cursor. TMS Up will ground stabilize the TD Box and automatically move SOI to the WPN Page. Then you slew the Mav seeker onto the target, TMS Up again to lock, and fire. I also highly recommend using the FOV button on the stick to toggle the Mav to NAR FOV, the missile will track much better that way.

 

The HUD TD Box represents the system designated target. It's a calibrated target location that's correlated with the INS/GPS system and precise range information from either TGP Laser Ranging, or FCR Ranging when the TD location is within LOS for those sensors (and in the case of the TGP, when the laser is armed).  This target designation ability is a baseline Viper function and independent of the TGP. A system very much like it can be used to designate targets for most weapons and slew the TGP onto a target seen through the HUD. This system is called DTOS, and isn't implemented yet.

 

The circle that appears once you start slewing the Mav seeker is the Mav seeker position (this will be approximate if you have not boresighted the Mav seeker, so its location relative to the TD Box may look weird). Moving the Mav crosshairs does not update the designated target point, that will remain at the TD Box location. This can be an important distinction, as the In Range cue on the WPN Page is based on the TD Box location, not the Mav seeker head location, so if they're significantly different your displayed range information will be incorrect. 

 

This delivery mode seems to be a WIP right now and not functioning entirely correctly. I believe when a missile is launched, the next missile in the sequence should snap to the current TD Box location, which would allow for rapid follow-on attack of an adjacent target just like you're asking for. But right now the next missile seems to  be sitting at boresight and not ground stabilized, despite the presence of a stabilized TD Box. That does not doesn't seem correct. You should also be able to cue up two Mavs with targets before even firing by using the MSL Step button on the stick. When you do that you should see two circles on the HUD marked "1" and "2" which indicate the seeker locations of both missiles. This doesn't work at all right now. 

[bart]

^^ Good post Bunny ^^

 

Thanks for the explanation, makes a lot more sense now. Hopefully will help OP out too.

[PicklePicklePickle]

10 hours ago, Bunny Clark said:

The HUD TD Box represents the system designated target. It's a calibrated target location that's correlated with the INS/GPS system and precise range information from either TGP Laser Ranging, or FCR Ranging when the TD location is within LOS for those sensors (and in the case of the TGP, when the laser is armed).  This target designation ability is a baseline Viper function and independent of the TGP. 

Amazing information! This is exactly what my question was, thank you. Ok, so the Viper without TGP does the TDC and ground stabilitization with no optical sensors, that is impressive. Without the TGP(no laser, no optical sensors), the ranging must be from the radar as you have said, much like the A-G gun STRF mode....very cool. I'm amazed that a GPS/INS is so precise that it can keep ground track even while the aircraft flies around.

 

I do agree it didn't make sense that once firing, the next maverick would not just slew to the TDC...i don't know what the real aircraft does but it seems logical.

 

I have to also admit, I don't understand why the maverick boresighting is not automated in the real aircraft. If you have the TGP loaded, it should be easy for software to aim the laser and have the system boresight each mavericks very precisely.  If the system can keep a ground track so effectively without a TGP, with a TGP it should be easy to automate it. But there seems to be wide evidence from real pilots that the manual procedure is how it works, and it seems to be done across multiple aircraft types like the A-10....

 

Anyway, thanks again!

[Machalot]

2 minutes ago, PicklePicklePickle said:

I'm amazed that a GPS/INS is so precise that it can keep ground track even while the aircraft flies around.

While this may be surprising at a gut level, it is literally the minimum requirement for an INS to function.  An Inertial Navigation System tracks the aircraft's position relative to an inertially fixed reference frame.  So it's trivial to calculate the line of sight to any inertially fixed point, or any point whose location is known.  (The Earth is not inertially fixed, but there is a relatively simple explicit formula for the inertial position and motion of all points of the Earth.)

 

If an INS can't do this, it's not an INS.

[Bunny Clark]

34 minutes ago, PicklePicklePickle said:

I have to also admit, I don't understand why the maverick boresighting is not automated in the real aircraft. If you have the TGP loaded, it should be easy for software to aim the laser and have the system boresight each mavericks very precisely.

Correlating the HUD and Radar is a fairly easy thing to do, both systems are fixed on the aircraft and aren't commonly removed. Once they're calibrated correctly they'll stay that way for a long time. The TGP is tightly mounted on a precision pylon and calibrated automatically on the ground, though this process does need to be repeated every time the pod is reinstalled on the aircraft. The problem is with the Maverick missile itself. It's not a sensor that's attached and stays attached, it's a weapon that is loaded per mission and needs to be able to fire. It can't be bolted super tightly to the airframe or it won't be able to launch when needed. The Maverick is slid onto a launch rail and held in place with a shear pin that breaks when the missile motor fires. So, there is necessarily some slop in the mounting, and no two missiles will line up exactly the same way on the rail. This means that the aircraft doesn't have a perfect idea where the missile seeker head is looking. It is certainly quite close without boresigting, but not perfect. I usually don't bother boresighting if I'm planning on using the VIS delivery mode, it's really only necessary for doing an Auto handoff in PRE mode with the TGP. 

 

The AGM-65D can't see lasers, so I'm not sure how firing the laser would help with boresighting. It's a fairly easy process to do while you're cruising to the mission area. Just remember when you're bored flying 15 minutes from your airbase to the mission location, it's time to spin up the Mavs and boresight them. 

[bart]

Great advice and info again, thanks Bunny.

[PicklePicklePickle]

This is really excellent information, thanks Bunny and Machalot!