I was wondering about this too and did some googling. https://iopscience.iop.org/article/10.1088/1742-6596/1510/1/012027/pdf https://iopscience.iop.org/article/

I was wondering about this too and did some googling. https://iopscience.iop.org/article/10.1088/1742-6596/1510/1/012027/pdf https://iopscience.iop.org/article/10.1088/1742-6596/1510/1/... indicates that it's probably above 900nm wavelength, as beyond that you get only minor interference from refracted solar radiation. It does say that higher in the atmosphere will always be better from an interference perspective (makes sense, as then there will be less atmosphere between the sensor and the stars), so that is why they market this specifically for use on aircraft. At 250k per unit it's not something you'll be able to mount on your car anytime soon.