You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Well, this was interesting (to me at least)...
I always thought a dedicated gps unit would be more accurate than a phone. So, I did a test. Exact same ride...Garmin 520 sitting in optimum position (handlebar mount) versus a Google Nexus 5 running Strava in my back pocket (roadie jersey) with gps aerial in optimum position. But, the [url= http://www.gpsvisualizer.com/display/20170529223047-69105-map.html ]results[/url] show otherwise!
If you switch to Open Cycle Map TF in top right corner, it shows how both units drift for the trail. Admittedly, this is under heavy tree cover but I won't bother using my 520 in those conditions any more as the Garmin under-records by about a third compared to the phone. (I did a similar test on the road and results are much closer so don't think you've wasted your money of you have a 520 for your road rides).
Is this not because you need to set the precision higher on the Garmin? I would certainly expect a true GPS, and a Garmin one especially, to have a better signal?
Did you have both GPS & Glonass turned on for the edge520?
There is no precision setting [i]per se[/i] that I can find for the 520 but GPS and Glonass are both enabled
For a valid test, you should really keep the devices at least 1 metre apart. The GPS radios can interfere with each other, otherwise.
Garmin dedicated device, configured correctly, will be more accurate. The software will still be utterly pants, though.
Rachel
The GPS radios can interfere with each other, otherwise.
They are a receiver only so this is bollocks.
There is something wrong with your 520
There is something wrong with your 520
I'd be inclined to agree with you but the test on the road would seem to dispute this...
The software will still be utterly pants, though.
Just in case anything went wrong between the Garmin Connect > Strava API, [url= https://connect.garmin.com/modern/activity/1762453065 ]here is the original Garmin Connect file[/url]
Oh yeah, another thing...I've chosen the current incline as one of the display fields and, on road rides, it's reasonably accurate, though it does lag reality a little.
In the trees, it's useless. Having said that, the climbing trail I went up is laughably steep and I was so pitifully slow, I suspect the barometer wasn't able to cope.
Anything to do with the phone using assisted gps? Assuming they still do. I imagine the triangulation with the phone masts etc may help or I may be miles off!
I'd be inclined to agree with you but the test on the road would seem to dispute this...
Poor antenna. Works fine in open sky, not under tree cover.
Or have you got smart recording turned on?
Anything to do with the phone using assisted gps? Assuming they still do. I imagine the triangulation with the phone masts etc may help or I may be miles off!
If anything, if you were solely relying on "assisted-gps" triangulation, the phone would (always?) be worse...
Or have you got smart recording turned on?
Hmmm...
<wanders off to find Garmin and read the manual...>
Having said that, the climbing trail I went up is laughably steep and I was so pitifully slow,
Auto pause turned on or off?
They are a receiver only so this is bollocks.
I suggest you learn a bit about heterodyne discrimination and how the receiver creates a known-frequency signal that is mixed with that received to get output before declaring something you clearly don't know *everything* about as "bollocks".
Rachel
520 is set to 1 second interval recording, not smart.
[s]Also, there is no auto pause setting that I'm aware.[/s]
Arse, just realized the auto-pause is actually part of the activity profile settings so I'll have to check each profile in turn...or I may need a new activity profile called "Very slow mountain bike climbs"...
Actually, what is the point of auto pause if you use Strava? AFAIK, Strava strips out any 'not moving' parts from the overall time to determine the moving time (though not segment times, which is fair enough)
I was thinking that Auto pause may have contributed to some of the straight lines you see that suggests a loss of gps for the garmin
what is the point of auto pause
if you're stopped with it still recording, it can add a mile or few over half an hour as the determined position drifts around your actual position.
If you know you're going 100 miles in a day and you stop for lunch and it adds 3 miles to your distance, you're going to be an unhappy bunny when the odometer trips over 100 and you've still got that climb to do!
Naff all use if you're out for a smash around the woods for an hour or 3, though.
Why would you expect a dedicated GPS to be better than a cycle computer or a smart phone? They all receive the same signals, so same information, the rest is just mathematics and there is no reason why all three devices shouldn't have the same mathematics within them - its just software. So taking antenna performance out of it why wouldn't you expect them to all provide the same answer?
taking antenna performance out of it
Why would you do that? That can be one of the main advantages of a dedicated GPS unit.
I wouldn't expect that much difference. Your slow climb through the trees will affect how long any drop out will be - as well as track position. I'd suggest that the 520 might benefit from a reset? I've found that over time my Garmin starts to loose accuracy (I only have a watch though), a soft re-set always sorts it out (I think it wipes the satellite memory)
I'd go with the phone. My pal always beats me no matter how long I've been waiting for him.
I'd like to see a review further exploring this, comparing more devices side by side.
I bought a 520 at the start of the month and noticed quite a large difference between the results from that and those off different model phones all using Strava. This was annoying and contributed to me returning the unit (the main reason though was it losing three miles of routes between creating it on the computer and moving it to the unit?!?)
It might be that the Garmin was correct on facts and figures but on one ride (about 22 miles long) their distance was within 0.1 miles and 1 ft of elevation of each other, mine was 0.4 miles lower and claimed i'd gone 250 ft higher? On another of similar distance theirs again were within 0.1 miles and 4 ft of each other, where the Garmin was 0.9 miles lower but claimed i'd climbed 260 ft higher?! Calories are way off too.
When i've been out with another friend with a Garmin 1000 his distance was the same as the phone guy (suggesting the 520 had issues) but again the elevation was off but not by as much as I was getting.
I'm currently waiting on an Elemnt Bolt, hopefully the mapping won't be an issue on that and the results will be more consistent.
Anything to do with the phone using assisted gps? Assuming they still do. I imagine the triangulation with the phone masts etc may help or I may be miles off!
I'd also read up on what assisted GPS actually is too.
If anything, if you were solely relying on "assisted-gps" triangulation, the phone would (always?) be worse...
I'd also read up on what assisted GPS actually is too.
Don't know if the Garmin does A-GPS, but if it does, I'd recommend doing a full online sync prior to the ride (edit: if it's not been fully synced for a couple of days). It should certainly help getting a good lock at the start. Might not help with the rest of the ride.
My Garmin, Polar and Phone are all reasonably consistent with each other. Although different apps on the phone or the internet either smooth out or make up additional distance or elevation gain (distance is less of an issue, elevation gain can vary considerably).
Steep climbs through tree cover are the worst possible conditions for a GPS when riding. The trees affect the GPS signals badly so you aren't getting an accurate position. On the devices you've listed, your ascent is calculated not measured, so it will be inaccurate (and therefore incline wrong). Useful despricption here [url= http://gpsinformation.net/main/altitude.htm ]http://gpsinformation.net/main/altitude.htm[/url]
Only a device with a barometric altimeter will give (more) accurate ascent. An 820 or Fenix watch for example.
Personally I've never found a bike GPS to be stunningly accurate under trees, so I always run a speed sensor on my mtbs to compensate and ensure at least speed and distance are accurate. Preference is still for a dedicated bike unit over a phone as it's a ruggedised device designed to be on handlebars, not a fragile £800 piece of consumer electronics.
taking antenna performance out of it
Why would you do that? That can be one of the main advantages of a dedicated GPS unit.
Because a poor antenna doesn't affect accuracy or precision. The unit either receives the signal and information being transmitted or it doesn't. If it doesn't then you simply don't get a reading, but if it does you will get a reading and that reading 'should' be the same across all the units IF they are all using the same mathematics and software.
I guess i'm just surprised as to why there should be a difference across the units in terms of the GPS location or if it is just an assumption. After all we know the story about the first Gulf War when the military needed more GPS units and couldn't get them so they upped the accuracy of the civilian network to equal that of the military one so they could provide the military with civilian units. So the inference being that a couple of hundred quid civilian unit is just as precise as a few grand of 'military spec' unit (just assuming the military were getting ripped off as they seems to always be with these things). So the precision depends upon the information contained within the GPS signal and not the unit itself. All the unit itself is doing is giving you different fancy features, which is what I assumed you'd be paying for in a GPS unit.
[quote=allthegear ]They are a receiver only so this is bollocks.
I suggest you learn a bit about heterodyne discrimination and how the receiver creates a known-frequency signal that is mixed with that received to get output before declaring something you clearly don't know *everything* about as "bollocks".
Rachel
on a consumer grade GPS, I'll update my stance to this is unnecessary bollocks... 😉
After all we know the story about the first Gulf War when the military needed more GPS units and couldn't get them so they upped the accuracy of the civilian network to equal that of the military one so they could provide the military with civilian units. So the inference being that a couple of hundred quid civilian unit is just as precise as a few grand of 'military spec' unit (just assuming the military were getting ripped off as they seems to always be with these things).
close. but not quite...
Because a poor antenna doesn't affect accuracy or precision
of course it can.
I have done a fair few tests with Garmin Vs iPhone...
My results found
[b]Accurate times = Garmin[/b] (1Hz), they were consistent runs and consistent times
[b]Fast times = iPhone[/b] (1Hz), they were not consistent, more often it knocked 10 seconds of a 2 minute run, occasionally added 5-10 seconds.
I spent a few mornings chasing my friends times and realised something was fishy when he started the trail, I waited 10-20 seconds, caught him up half way down the trail and then compared times and he was quicker than me.
I have also used a dedicated BT GPS XGPS160 (10Hz), but don't have a conclusion yet as I have only used it twice on the bike.
I will also say you cannot use Google Sat View as a way of seeing if its accurately tracing the trail.
Different GPS units use different chipsets and software.
I have a few different units. One of which is a Trimble commercial unit I picked up cheap on Ebay. It is way more stable and accurate than the others, no idea why, it isn't a differential unit or anything else fancy.
What's also weird is that it shows a very high HDOP, which should mean the position is pants but it's not.
Because a poor antenna doesn't affect accuracy or precision. The unit either receives the signal and information being transmitted or it doesn't. If it doesn't then you simply don't get a reading, but if it does you will get a reading and that reading 'should' be the same across all the units IF they are all using the same mathematics and software.
It either receives valid information [i]from an individual satellite[/i] or it doesn't. If you've locked on to a satellite and I've locked on to twelve, who's going to have the more accurate location data?