GPS Problems

Love the site and have subscribed as so impressed with route planning and ease of use. One area I’m having major issues with is the inaccuracy of the GPS location indicator when out on a rider. Using mobile phone to follow route it frequently indicates my “location” 100s of metres from my actual point on the route ( often planned route not visible on screen) . Have to keep Google maps/Cyclestreets running in background as their GPS locators are significantly more accurate ( although none 100% accurate all the time ) for directions at junctions etc. in case cycle-travel shows me in a field or on a motorway. Is this a common problem or is there something I can do to improve the accuracy.