GPS and running

I’ve started running again (while I hadn’t run for ages) and I’m using my Garmin Forerunner 301 as a personal trainer loadign it with selected training exercises - this month is cardio training - and although as a personal trainer it does a great job with heart & time monitoring it’s not so good when it comes to calculating speed based on GPS signals, check on the map below to see how inaccurate those are. Any one know how to enhance that ?






