Shahab-3B
The Shahab-3B differs from the basic production variant. It has improvements to its guidance system and warhead, a few small changes on the missile body, and a new re-entry vehicle whose terminal guidance system and rocket-nozzle steering method are completely different from the Shahab-3A's spin-stabilized re-entry vehicle.
The new re-entry vehicle uses a triconic aeroshell geometry (or 'baby bottle' design) which improves the overall lift to drag ratio for the re-entry vehicle. This allows greater range maneuverability which can result in better precision. The triconic design also reduces the overall size of the warhead from an estimated 1 metric ton (2,200 lb) to 700 kg (1,500 lb).
The rocket-nozzle control system allows the missile to change its trajectory several times during re-entry and even terminal phase, effectively preventing interceptor guidance via trajectory prediction by early warning radar - a method nearly all long range ABM systems use. As a high-speed ballistic missile and pre-mission fueling capability, the Shahab-3 has an extremely short launch/impact time ratio. This means that the INS/gyroscope guidance would also remain relatively accurate until impact (important, given the fact that the gyroscopes tend to lose accuracy with longer flights). The CEP is estimated to be at 30–50 metres (98–160 ft) or less. However, the accuracy of the missile is largely speculative and cannot be confidently predicted for wartime situations.
These improvements would greatly increase the Shahab-3B's survivability against ABM systems such as Israel's Arrow 2 missile as well as being used for precision attacks against high value targets such as command, control and communications centres.
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Shahab 3 engine
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