Sales of GPS navigation units seeing triple-digit growth

Industry sold 2.2M units in 2006; could reach 3.3M in 2007

Experts cite lower prices, increased portability

GPS systems found in autos can cost 50%-80% more than new hand-helds

Yet offer similar features like turn-by-turn navigation

Experts say hand-held will outnumber built-in systems by 2-to-1

"A lot of no-name Chinese companies have entered the market. But top-tier manufacturers have also introduced lower prices to reach a larger demographic and pass on savings that come with bigger scales of economy." -- Ross Rubin, analyst, NPD Group