BonsaiNut
iMTB Rockstah
Got a new dual frequency GPS watch for Christmas, and thought I would share some feedback - specifically on GPS accuracy.
Old watch: Garmin Forerunner 645 Music (single band GPS)
New watch: Garmin Forerunner 255 (dual band GPS)
A lot of my biking in NC consists of winding trails with sharp turns and switchbacks. GPS devices struggle with accuracy on these trails - particularly with bikes (and faster speeds). I could use my old watch and measure a bike ride, a run, and a hike on the same trail, and get a wide range of results - always under-reporting the distance:
Mountain biking: 8-10% under reported
Running: 5-7% under rep0rted
Hiking: 5% under reported
This contrasts to a straight trail, for example, where the watch would report the same starting point, the same ending point, and even if the middle points were somewhat inaccurate, the total distance reported was usually pretty consistent.
So when the time came for a new watch, I specifically bought one with a dual band GPS and was looking forward to testing them next to each other. Yesterday I rode a 13.0 mile trail that I ride regularly - with the 13.0 miles consistently reported via both the official trail map as well as my Cateye wheel sensor. Both watches were worn simultaneously. End result:
Dual band: 12.29 miles (-5.5% inaccurate)
Single band: 11.80 miles (-9.2% inaccurate)
Actual distance: 13.0 miles
So the dual band cut the inaccuracy by about 50%. Almost as important, the course mapping accuracy improved dramatically. Examples:
Out and back consistency (when you travel the same trail segment out and back, does the GPS accurately portray the segments overlying each other?)
Single band GPS:
Dual band GPS:
Cross-over errors. When mapping switchbacks and trail sections that run close to each other, is the GPS accurate enough to avoid showing cross-over errors? (trails inaccurately crossing over each other?)
Single band GPS:
Dual band GPS:
Finally, elevation accuracy improved significantly over trails that had short climbs and drops - the single band GPS reported the trail having 344 feet of elevation(!), the dual band GPS reported 978 feet of elevation. Google Earth corrected elevation mapping suggests 1,141 feet. (Hard to tell accurately, but trail is probably around 1,400).
Overall, I am pleased with the improvement, and am looking forward to testing both watches on runs and hikes.
Old watch: Garmin Forerunner 645 Music (single band GPS)
New watch: Garmin Forerunner 255 (dual band GPS)
A lot of my biking in NC consists of winding trails with sharp turns and switchbacks. GPS devices struggle with accuracy on these trails - particularly with bikes (and faster speeds). I could use my old watch and measure a bike ride, a run, and a hike on the same trail, and get a wide range of results - always under-reporting the distance:
Mountain biking: 8-10% under reported
Running: 5-7% under rep0rted
Hiking: 5% under reported
This contrasts to a straight trail, for example, where the watch would report the same starting point, the same ending point, and even if the middle points were somewhat inaccurate, the total distance reported was usually pretty consistent.
So when the time came for a new watch, I specifically bought one with a dual band GPS and was looking forward to testing them next to each other. Yesterday I rode a 13.0 mile trail that I ride regularly - with the 13.0 miles consistently reported via both the official trail map as well as my Cateye wheel sensor. Both watches were worn simultaneously. End result:
Dual band: 12.29 miles (-5.5% inaccurate)
Single band: 11.80 miles (-9.2% inaccurate)
Actual distance: 13.0 miles
So the dual band cut the inaccuracy by about 50%. Almost as important, the course mapping accuracy improved dramatically. Examples:
Out and back consistency (when you travel the same trail segment out and back, does the GPS accurately portray the segments overlying each other?)
Single band GPS:
Dual band GPS:
Cross-over errors. When mapping switchbacks and trail sections that run close to each other, is the GPS accurate enough to avoid showing cross-over errors? (trails inaccurately crossing over each other?)
Single band GPS:
Dual band GPS:
Finally, elevation accuracy improved significantly over trails that had short climbs and drops - the single band GPS reported the trail having 344 feet of elevation(!), the dual band GPS reported 978 feet of elevation. Google Earth corrected elevation mapping suggests 1,141 feet. (Hard to tell accurately, but trail is probably around 1,400).
Overall, I am pleased with the improvement, and am looking forward to testing both watches on runs and hikes.
