Mission Control Mission Control GPS Errors?

1983RH

Well-known member
Apr 5, 2021
15
28
Santa Rosa
I've had no issues for a number of rides recording them using the Mission Control App on 2022 Gen 3 Turbo Levo. Then got this where the GPS track got wonky (long straight line). The odd thing is it did not count the milage in the wayward straight segment. I rode with a new TL owner today who used the app for the first time, first ride, and it only recorded a straight line with no data? Anyone else have this happen, any ideas on how to prevent this?

Thanks!
Screen Shot 2021-04-19 at 2.32.09 PM.png
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,103
4,632
Weymouth
...use a decent gps logger!! The straight line is because the Levo lost contact with sufficient satellites. Many phone GPS systems suffer the same errors although some are better than others because they use a good quality GPS chip....which cost money!!

A decent GPS chip will link to up to 10 satellites and record a track point every tenth of a second............you will not get that sort of performance from a cheap phone..or TCU GPS chip.
 

1983RH

Well-known member
Apr 5, 2021
15
28
Santa Rosa
...use a decent gps logger!! The straight line is because the Levo lost contact with sufficient satellites. Many phone GPS systems suffer the same errors although some are better than others because they use a good quality GPS chip....which cost money!!

A decent GPS chip will link to up to 10 satellites and record a track point every tenth of a second............you will not get that sort of performance from a cheap phone..or TCU GPS chip.
Any recommendations for an iPhone 12? Is the logger software or hardware to interface with my phone?

thanks!
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,770
20,451
Brittany, France
Sometimes if you step away from the bike with your phone it drops the connection and then doesn't auto re-connect - even if you have "auto-connect turned on - I guess you'd call it a bug ! So if you do ever walk away from the bike, check Mission Control when you get near again.

It could also be something power saving on the phone which turned the GPS off.
 

MrSimmo

E*POWAH Elite
Apr 24, 2020
1,048
985
The Trail.
Any recommendations for an iPhone 12? Is the logger software or hardware to interface with my phone?

thanks!
The iPhone 12 has an excellent gps system in it with good features such as a barometric altimeter etc. I think DC Rainmaker and some others did a through test and found it nearly as good as the dedicated Garmin/Wahoo type devices. So if you follow that train of thought, I’d suggest a software solution:

There are loads and there are various threads on it on the forum but check out these apps as a start:

- Blevo
- Komoot
- Cyclemeter
- MapMyRide
- RideWithGPS
- Strava
- Apple’s own fitness app

Mikerb is spot on though, a dedicated device may be able to improve on GPS accuracy for the reasons he mentioned ?
 
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Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,103
4,632
Weymouth
For riding I just use Strava on my Phone ( Samsung a21S/Android). I have a tracker on my bike as a anti theft device. The track data recorded by the tracker is nowhere near as accurate as the phone/Strava track...............but then it is primarily used to alert me if the bike moved out of a security fence set up on the tracker........I just leave it in the bike all the time and occasionally take a look at its history....so I accept it is not brilliant at recording loads of track points. The phone/Strava does a decent job at least in this area which has no deep cut valleys.

I used a dedicated GPS device for windsurfing which costs a lot more than a mobile phone. Its ability to guarantee a fix onto several satellites at a time ( and showing/recording how many it is connected to at all times), its tracking point recording rate and ability to use dopler techniques to accurately record speed, makes it an approved device for windsurfing speed events. I have used the same device for orienteering and it is accurate to about 1 metre and works in mountainous and forested areas. You pay your money and take your choice!!
 

silverstone

Member
May 20, 2019
62
60
Switzerland
I have this failure also a lot of time.
Should be an easy fix for the MissionControl developper team, to implement an algorithm, which detects "false positive" gps positions and delete them!
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,103
4,632
Weymouth
Those straight line tracks are not due to "false positives". They are due to a period of time when no track points were recorded due to not having sufficient satellite contact. That is often due to firstly the GPS chip being used not tracking sufficient satellites and/or terrain that blocks contact such as deep steep sided valleys or tall structures. The gap between losing cross navigation reference and the next successful recording of a track point will be a straight line.
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,770
20,451
Brittany, France
I have this failure also a lot of time.
Should be an easy fix for the MissionControl developper team, to implement an algorithm, which detects "false positive" gps positions and delete them!
There is a thread for feedback to Specialized :

 

1983RH

Well-known member
Apr 5, 2021
15
28
Santa Rosa
Those straight line tracks are not due to "false positives". They are due to a period of time when no track points were recorded due to not having sufficient satellite contact. That is often due to firstly the GPS chip being used not tracking sufficient satellites and/or terrain that blocks contact such as deep steep sided valleys or tall structures. The gap between losing cross navigation reference and the next successful recording of a track point will be a straight line.
Thanks for the info. The weird thing about that track was I never went to the other end of it and when it did this I was at a turn around for an out and back at the top of a mountain with no overhead obstructions. But in any case, I am confident the issue is with the Mission Control App. I have a slew of other GPS apps on my phone that don't exhibit this behavior.
 

silverstone

Member
May 20, 2019
62
60
Switzerland
Those straight line tracks are not due to "false positives". They are due to a period of time when no track points were recorded due to not having sufficient satellite contact. That is often due to firstly the GPS chip being used not tracking sufficient satellites and/or terrain that blocks contact such as deep steep sided valleys or tall structures. The gap between losing cross navigation reference and the next successful recording of a track point will be a straight line.

No sorry, your not right! The straight line goes to a point I never was, and then directly back to my route.
And some times it goes away from my location more tha a few miles. It's not like it was not tracking for a long period of time, and then it goes straight to the point I am, as soon as it has a valid signal again. So in my opinion it IS a falso positive...
 

MrSimmo

E*POWAH Elite
Apr 24, 2020
1,048
985
The Trail.
No sorry, your not right! The straight line goes to a point I never was, and then directly back to my route.
And some times it goes away from my location more tha a few miles. It's not like it was not tracking for a long period of time, and then it goes straight to the point I am, as soon as it has a valid signal again. So in my opinion it IS a falso positive...

There's a setting which quite a few developers do not take advantage of in iOS (the software iPhones run) - it increases GPS accuracy at the expense of battery life - it essentially tells the GPS subsystem to check in more frequently using multiple GPS services. ViewRanger for iOS supports this feature, not sure anyone else does.
 

Rusty

E*POWAH BOSS
Jul 17, 2019
1,513
1,673
New Zealand
I have found that turning off 'Improved Accuracy' on a Samsung phone and using GPS only gives me much more accurate tracking.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,103
4,632
Weymouth
yes you can get anomalies due to both weak and bounced signals which is why good GPS chips grab several satellites ( my Locosys GPS grabs 10 at a time) and constantly monitor those with the strongest signal, only using those strongest signals. It typically requires 4 to produce a cross reference location. The next issue is the usual bottleneck in non dedicated GPS devices.........buffer size, processing power and storage.
 
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