A transporter erector launcher (TEL) is a missile vehicle with an integrated prime mover (tractor unit) that can carry, elevate to firing position and launch one or more missiles. Such vehicles exist for both surface-to-air missiles and surface-to-surface missiles. Early on, such missiles were launched from fixed sites and had to be loaded onto trucks for transport, making them more vulnerable to attack since once they were spotted by the enemy they could not easily be relocated, and if they were it often took hours or even days to prepare them for launch once they reached their new site.
The term can also refer to support structures used to transport a rocket launch vehicle horizontally from an assembly facility to a nearby fixed launch pad where it is raised vertical for launch. This system is used, for example, by SpaceX for its launch vehicles.
A transporter erector launcher and radar (TELAR) is the same as a TEL but also incorporates part or all of the radar system necessary for firing the surface-to-air missile(s). Such vehicles have the capability of being autonomous, greatly enhancing their effectiveness. With this type of system each vehicle can fight regardless of the state or presence of support vehicles. The TEL or TELAR may have a rotating turntable that it can use to aim the missiles. The vehicle may have to turn to aim the missiles or they may fire straight up.
Conversely, a transporter launcher and radar (TLAR) is the same as a TELAR without the erector capability, because the missile in question is transported in the launch-ready position. An example is the 9K330 Tor, which mounts a Vertical Launching System-style block of SAMs.
Usually a number of TELs and TELARs are linked to one command post vehicle (CP or CPV). They may use target information from Target acquisition, designation and guidance radar (TADAGR) or, simply, TAR.
A Russian S-300V TELAR in transit mode.
A Russian S-300P TEL ready for launch.
A French Pluton missile in transit mode.
Russian Topol-M MZKT-79221.
HQ-9 TA580/TAS5380 launcher.