Today Reuters reported : Sources close to the Investigators believe the truck bomb was detonated remotely, possibly by an infrared device to bypass jamming equipment in Hariri's motorcade, the source added.
That is the most plausible technical explanation I have heard in relation to the mode of triggering of the truck. As the Motorcade of Martyr Hariri was equipped with Radio Frequency Jamming Devices that spread over a wide spectrum of frequencies. Since Infrared is not a RF Signal, it is rather Energy (or as commonly known as heat) it can bypass all the RF jamming equipment the motorcade was equipped with.
For example, a person's body generate some sort of Infrared Energy in the surroundings, and the principle of alarm detection is based on detectors that detect this infrared energy emitted by the body or an external source and triggers an alarm.
a) Line of sight
b) The assassin will be equipped with a High power infrared transmitter, such as a laser link (which can have a distance in Kilometers); or even something similar to the Military laser used to paint targets making them easy for airplanes to hit
c) A receiver to be mounted on the truck
d) The receiver connected to a relay and hence to a triggering device..
Once the motorcade of Martyr Hariri passed next to the truck, the assassin fired or pushed on a button causing the transmitter to send an infrared energy that is picked up by the receiver, and hence detonation.
To make it simple for non technical persons, I do not know if you watched Arnold Swazinger's movie "Predator", well the idea of the movie is that the alien sees the infrared energy transmitted by the person to locate his presence.. Now there is a device that generates high power infrared energy that travels through kilometers... And this is the sort of thing Reuters was referring to.
To make it more simpler, take the TV or Stereo remote control (which works on the Infra Red technolgy, with the receiver built in the TV set), it has a range of several meters. Think of a similar device but with hundreds of meters range, so a similar device could have been the trigger.
That is something I never thought off.... So as Jamil Sayed said, the assassin is either an Einstein or a jackass, I think what best describes him as Mikari said (A jackass who thought he was Einstein)
