Some more info from new French books on the Jaguar and Mirage:
The initial Martel had three homing heads. The homing head had to be chosen according to the type of target being engaged. Martel sorties were highly planned and intelligence intesive.
As the Mirage IIIE lacked ELS, a poor mans ELS was developed using a wideband receiver mounted in the front of a modified fuel tank. This device obtained long range passive contacts and the pilot was to follow indications. Once in range of the Martel seeker, this was turned on and let to scan. There was an indication inthe cabin showing the missile line of view. The pilot followed this path until getting a green light from the missile indicating a solid lock. Of course, there was no range indication, although it could be calculated using the info of the homing tank and the RWR based on signal intensity.
ARMAT was a private development using and improved, wideband ESD seeker. The French government and Air Force weren`t quite worried about exporting MArtel/ARMAT and the export missile, while having the wideband receiver, seems to have had degraded capabilities.
French missiles were upgraded in the late 1980s using the ARMAT technology to a wideband homing head. With the retirement of the Mirage IIIE, Jaguar became the sole platform. Jaguar EW equipment was quite poor, so Martel missions requiered a lot of work asn shown during its sole use in combat by the AdA agaisnt Lybia.
It was retired in the late 1990s due to age, costs and suspected reliability.