December 5, 2010: Israel has finally come to the conclusion that the U.S. use of GPS guidance in rockets, while more expensive, was more effective than the cheaper (but less accurate) Israeli developed rocket guidance system, and even cheaper unguided artillery shells. During the 2006 war with Hezbollah, the Israelis found that they did little damage to Hezbollah bunkers, even though over 120,000 unguided shells were fired at them. Meanwhile, they noted that the U.S. 227mm MLRS rockets, with GPS guidance, were excellent at taking out similar targets in Iraq and Afghanistan. So Israel has equipped its 160mm Accular rockets with GPS. These 110 kg (242 pound) rockets have a range of 40 kilometers, and enable one bunker to be destroyed with one rocket.
Instead of adopting GPS guidance, in the last five years, Israel developed cheaper, but less accurate, systems for their rockets. The main effort here was the Trajectory Correction System (TCS), which was installed in U.S. 227mm MLRS unguided rockets as well as Israeli 160mm rockets. TCS used rockets equipped with a guidance system and radio. The ground portion of TCS consists of a control unit that tracks the position of the rockets in flight, calculates where they will land, and sends orders to the guidance system (small vanes) in the rocket. This makes the rockets as accurate as unguided artillery shells. TCS is cheaper than GPS guided rockets. Israel bought 48 MLRS launchers in the 1990s, but has mostly used them to fire unguided rockets.
In some situations, Israel always recognized the superiority of GPS. For example, Israel developed LORA (Long Range Artillery Rocket), which is similar to the U.S. ATACMS. Each LORA missile weighs 1.23 tons and carries a half ton warhead. With a range of 300 kilometers, GPS guidance is used to land the warhead within 10 meters (31 feet) of the aim point. These missiles are expensive however (ATACMS, which is fired from a MLRS containers that normally carries six of the standard MLRS rockets, cost a million dollars each.) It's cheaper if you can use smart bombs. But if you don't have aircraft up there, or control of the air is contested, you can get a LORA missile on a target within ten minutes of the order being given.
Israel expects to replace a lot of air delivered missiles and bombs with its GPS guided rockets, and take out more targets with far fewer rockets and artillery shells.