A system for obtaining calibrated spectral measurements of a target, the system comprising: an aerial vehicle; at least one spectral imaging device configured to obtain spectral measurements of a target wherein the target is at least partially illuminated by one or more ambient light sources, such that a first set of target spectral measurements are obtained for a target; at least two photo sensors configured to obtain spectral measurements of the one or more ambient light sources, wherein the at least two photo sensors have peak responses approximate to a first set of discrete spectral frequency ranges and are configured to obtain a first set of ambient light spectral measurements of the one or more ambient light sources at individual ones of the first set of discrete spectral frequency ranges, wherein the at least two photo sensors comprise a first photo sensor having a peak response approximate to a first spectral frequency range of the first set of discrete spectral frequency ranges and being configured to obtain a first spectral measurement of the one or more ambient light sources over the first spectral frequency range and a second photo sensor having a peak response approximate to a second spectral frequency range of the first set of discrete spectral frequency ranges and being configured to obtain a second spectral measurement of the one or more ambient light sources over the second spectral frequency range; wherein the at least one spectral imaging device and the at least two photo sensors are carried by the aerial vehicle; and one or more processors configured to obtain time and position information, and attitude information for the at least one spectral imaging device and/or the at least two photo sensors, associated with the obtained measurements, wherein the time and position information, and the attitude information, is concurrently obtained with the spectral measurements of the target and the one or more ambient light sources; wherein the system is adapted to use the obtained spectral measurements of the one or more ambient light sources, the time and position information, and the attitude information, to calibrate the obtained spectral measurements of the target, such that the first set of target spectral measurements are calibrated based on the first set of ambient light spectral measurements, the time and position information, and the attitude information. an aerial vehicle; at least one spectral imaging device configured to obtain spectral measurements of a target wherein the target is at least partially illuminated by one or more ambient light sources, such that a first set of target spectral measurements are obtained for a target; at least two photo sensors configured to obtain spectral measurements of the one or more ambient light sources, wherein the at least two photo sensors have peak responses approximate to a first set of discrete spectral frequency ranges and are configured to obtain a first set of ambient light spectral measurements of the one or more ambient light sources at individual ones of the first set of discrete spectral frequency ranges, wherein the at least two photo sensors comprise a first photo sensor having a peak response approximate to a first spectral frequency range of the first set of discrete spectral frequency ranges and being configured to obtain a first spectral measurement of the one or more ambient light sources over the first spectral frequency range and a second photo sensor having a peak response approximate to a second spectral frequency range of the first set of discrete spectral frequency ranges and being configured to obtain a second spectral measurement of the one or more ambient light sources over the second spectral frequency range; wherein the at least one spectral imaging device and the at least two photo sensors are carried by the aerial vehicle; and one or more processors configured to obtain time and position information, and attitude information for the at least one spectral imaging device and/or the at least two photo sensors, associated with the obtained measurements, wherein the time and position information, and the attitude information, is concurrently obtained with the spectral measurements of the target and the one or more ambient light sources; wherein the system is adapted to use the obtained spectral measurements of the one or more ambient light sources, the time and position information, and the attitude information, to calibrate the obtained spectral measurements of the target, such that the first set of target spectral measurements are calibrated based on the first set of ambient light spectral measurements, the time and position information, and the attitude information.