What i have seen of drones, are that they are kept aflight by electrical motors, unless we are talking the ones that are actual airframes with missiles under the wings, which are not ‘drones’, but ‘remotely piloted vehicles’.
Electrical motors do not put out much of a heat signature, considering that the motors are cooled by the very propellers they power.
The ‘rpv’s’ actually use turboprops or small jet engines, either of which DO create a heat signature.
The ‘chapparal’ system was a tracked/wheled vehicle with four Sidewinders mounted. Another heat-tracking missile is the Stinger shoulder fired missile, which also was mounted on wheeled vehicles, and as an R&D project, mounted on the turret of tanks, and lastly, mounted on the turret of the PHALANX CIWS system, mounted on either wheeled/tracked vehicles.
I believe the AIM-9X and similar missiles have imaging IR seekers that are far better suited for track low-heat and stealth targets.