Throughout the day satellite's come and go as they move throughout their orbit. You might have 7 satellites but if they are all located on the horizon or straight up they are useless. More than likely that is what he experienced. When surveying we have to plan the best time of day to accomplish the most amout of work. at "bad" times we try to work out in the open or just go to lunch. I'm not discounting that the govt was jacking them up, but considering all the different systems that rely on GPS data transmissions I would think it highly unlikely. The DOD also works off of satellites that we don't have access to.
You can plan to work during peak times here but it don't do you much good for fishing because the type of accuracy needed for surveying is not needed to locate brushpiles.
http://www.geosystems.co.nz/support/....html?item=366