1. A calibration system for an infrared imaging system including an infrared sensor having a sensor model for imaging a target having a target spectral signature, the infrared imaging system including an atmospheric model having atmospheric values, the calibration system comprising: a blackbody calibration source having a calibration source spectral signature; and a computer for receiving the sensor model, the target spectral signature, the calibration source spectral signature and the atmospheric values and performing at least one of the following operations: predicting a target spectral signature propagation at the infrared sensor; matching the target spectral signature propagation with the calibration source spectral signature propagation; and determining a blackbody calibration source temperature for radiometric calibration of the infrared sensor.