Nav system in map mode beeps and changes addresses

[bellevuecolt]

When my nav system is in Map mode it frequently starts beeping and the the screen shows a red circle with crosshairs in the center. Sometimes the screen changes street and town addresses. At other times the screen shows the circle and crosshairs without an address and a dotted line going left and downward from the crosshairs to the lower left edge of the screen along with a distance in miles that constantly changes. My dealer has replaced the head unit 2x and after each change the unit starts malfunctioning again with a couple of days. The malfunctioning increases in frequency with the passage of time.
Today I was stopped for a red light when the beeping started and I happened to noticed that the speedometer did not read zero. Instead it showed a top view of my car and the front and rear sensor areas all in gray.