A scenario: I'm flying east in a plane on the left side of the plane which means I'm looking to the north from my seat. I look down and see land but no major highway. On my GPSr, I see my position as being south of, say, Interstate 80. Given my postion on the GPSr, I should be looking down and seeing the highway. I can't see the highway even looking as straight down as I can.
I've chalked this up to the fact the few satellites I'm receiving are all on my side of the plane and their angle pointing down at me would position me south of my real position. However, the GPS experts I have asked say that even those few satellites I'm receiving signals should accurately indicate where I am regardless of the fact that I'm seven miles up in the air and traveling over 500 miles per hour.
I have a Garmen emap. Has anyone else had similar experiences? Could there be a parallax issue with less expensive/smaller GPSr's?
Hal