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Hi a simple question i hope someone can help me with. Does anyone know irl why the usaf and navy use both jdam and paveway kits for the dumb bombs. I know lgb is generelly for moving targets but surely there has to be a bigger reason now that both jdam and paveway series use both laser and gps.

In simplicity one is a laser unit and the is GPS I think could right out of whack with the answer though.

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That's complicated!

LGBs are better for moving targets, that's true, but there's other reasons one might choose one over the other. The big one is weather. JDAM is more useful in poor weather and smoke. The laser can be affected by moisture or particulates in the air, which might make the LGBs less accurate or even miss.

ORIGINAL: Lassekongo

Hi a simple question i hope someone can help me with. Does anyone know irl why the usaf and navy use both jdam and paveway kits for the dumb bombs. I know lgb is generelly for moving targets but surely there has to be a bigger reason now that both jdam and paveway series use both laser and gps.

In general Laser guided bombs are better at hitting an exact spot so for example if you need to drop a bomb down an air duct and into a bunker or something you would use laser guided. However laser guided bombs as mentioned before require minimal cloud cover (or flying below the clouds) and lower dust levels and can't see through smoke very well. GPS guided bombs are only as a ccuratw as GPS which is measured in 1-10m depending on conditions whereas a laser guided bomb is accurate within centimeters. GPS guided bombs are however operable in all conditions and have the not yet mentioned major advantage of allowing the launch platform to drop and then immediately turn and run unlike laser guided bombs which require designation until impact either keeping the launch platform loitering or ground forces uncomfortably close

I'm really not able to speak to their accuracy. JDAMs are, however, potentially subject to GPS jamming, which is another consideration that might influence the choice of LGB versus GPS guided weapons. That's an effect not captured in Command.

I think it's a case of using the right tool for the job.

Each combination of bomb, fuse, guidance kit and delivery platform will give you a different set of parameters. Glide range, penetration distance, blast radius, angle of attack, terminal velocity etc. Accuracy and guidance mechanism are important factors but there are others.

I think we'll have a mix of LJDAM & Paveway for some time to come.

I think the OP's question was more why doesn't the USN and USAF always use the bombs that contain both laser guidance sensors and INS/GPS sensors, for instance the GBU-49 GPS Paveway and the GBU-54 LJDAM, and not what the strengths of each type of guidance are, seeing that he ends his question with "now that both jdam and paveway series use both laser and gps"

The only reasonable qualified guess I can give is that:
1) the US armed forces already have very large stocks of especially Paveway II laser guidance kits and also standard JDAM inertial navigation/GPS-guidance kits that they have to use up
and
2) in the light of the OP's question a lesser, though not negligable, concern is cost.
It stands to reason that a guidance kit that only uses one type of sensor will be cheaper to produce than one who incorporates both a laser sensor and a inertial navigation system plus GPS-receiver (Nowadays also preferably a spoof-secure GPS-receiver, with GPS-spoofing becoming a larger and larger concern with the near-peer or even peer threats that now exists or will exist in a very short time - In other words, China).
and
3) If I am still up to date in my knowledge: For specifically the USN, the LJDAM and GPS Paveway for the Mk83 1000 lbs bomb is not even being produced (Are there even plans for those kits?) as of now and for the USAF the stocks of LJDAM and GPS Paveway kits for Mk84 2000 lbs bombs and BLU-109s are surely very to quite small since it was only recently they were brought into production.

The other factor that sometimes rules out JDAM is when the launching aircraft doesn't have precise targeting data or a reasonable way to get that from datalink or what have you. A FAC or troops on the ground with a designator or a second aircraft with a targeting pod can provide guidance for a "blind" aircraft just acting like a bomb truck just by making sure the launcher has the right code to program into the bomb before launch (which is relatively easy to do and in some cases can even be pre-briefed).

ORIGINAL: LargeDiameterBomb

It stands to reason that a guidance kit that only uses one type of sensor will be cheaper to produce than one who incorporates both a laser sensor and a inertial navigation system plus GPS-receiver

Simple Paveway kit (laser only) is about 20K USD. The cheapest JDAM kit (GPS only) is about 25K USD. The combined solutions like Paveway IV and LJDAM are 50K+ at best.