Airport International have recently published an article describing how Tarsier can be used during snow operations.
Here are a couple of extracts:
snow banks will be present on the runway edges, potentially limiting a system’s line of sight
The elevated location of the sensors [Tarsier sensors] means they see clear over snow banks
The above is clearly a criticism of the FODetect system from Xsight, which has sensors located on the runway shoulders, adjacent to the runway lights.
It’s a valid criticism, but it’s not just snow banks that can cause a problem for FODetect. With the fragile sensors located alongside runway lights they are also prone to accidental damage from aircraft and ground vehicles. And of course when a sensor is damaged you don’t just lose detection coverage, you also have a potential FOD problem i.e. the damaged sensor itself will become FOD (FOD that you can no longer detect!). It’s the greatest risk associated with such a system, and given the lack of sales by Xsight it appears to be a risk the airports are not willing to take.