Assuming your helicopter is going to be operating outdoors you would want to follow a procedure different from that engaged in by pictorial photographers. Accepted practice for remote sensing operations is to radiometricaly calibrate your camera system. This means to establish a standard illuminant and record the camera's channel-specific response curves.

Opto-electronic engineers will accomplish this task using an integrating sphere and bit-wise access to the digital response of the sensor. Once response is characterized, a transfer curve can be used to calibrate the total system response to an absolute radiometric state. This is generally accomplished by applying a RGGB transfer curve between the debayer and demosaic steps of post processing. If you have imagery in a known radiometric state you can then reconstitute it in any other color space or appearance you like.

This engineering rigor can be approximated using more readily available materials. The illumination on a bright, sunny day at noon at a moderate latitude is well known. If an image of a reliably uniform and spectrally balanced subject is captured under these conditions, a reasonable (accurate to around 3%) characterization can be made. To ensure the accuracy of your calibration, be sure to double check the spectral characteristics of your subject (for example, check it's metamerism properties) and also use varied exposure to investigate the toe and shoulder of your response curve.

Remember that in remote sensing applications we prefer imagery that is uniform to that which is pretty. Use rigorous calibration, be meticulous with your ground truth and good looking pictures will be a natural by-product.