Best GPS Sensor for iOS

Discussion related to external and internal GPS / GLONASS / Galileo / BeiDou sensors
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Fredman6
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Best GPS Sensor for iOS

Post by Fredman6 »

Hello All,

I have been using HLT for years now and want to invest in a GPS sensor for more accurate times. I looked at Harry's current list of iOS approved sensors (https://www.gps-laptimer.de/compatibility/ios) and the Dual 160 XGPS is listed at the top. Racelogic is also recommended but I see its price point is almost 2.5 times that of Dual 160. Lots of folks at my club use Garmin Glo 2 (but not HLT) and I see that's not recommended for iOS.

I researched the Dual 160 and it doesn't have too favorable of reviews on-line; issues from it being off position, to gaps in data to bad batteries that stop holding a charge after a few uses. Racelogic is a lot more money, but don't see many reviews on it, the few I found were favorable.

I want something of quality that will just work. What is the best iOS compatible GPS sensor to get?

Thanks for the advice.
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Tripper
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Re: Best GPS Sensor for iOS

Post by Tripper »

I'm also looking for a new GPS. I have used the Dual 160 (battery won't charge after a few uses, after about a year it just stopped working even when plugged in) and the Bad Elf (lightning connector) which is totally inaccurate.

See attached image: the smooth red line is a lap recorded by the Dual 160, the green line is a lap on the same track recorded using the Bad Elf.
bad elf.jpg
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So I can't help except to steer you away from those two. Hopefully somebody will chime in with something they're happy with.
Fredman6
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Re: Best GPS Sensor for iOS

Post by Fredman6 »

Thanks for the input. It looks like I should investigate the more expensive Racelogic device. I'm ok spending the extra money if it just works. Don't want to spend time at the track troubleshooting stuff.
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Harry
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Re: Best GPS Sensor for iOS

Post by Harry »

For a consumer level device, the red line is actually pretty amazing. I use my 160 for more than five years already, and it always worked fine. Looking into the BadElf plot - it is bad. However, it is probably worth checking the mounting position of your smartphone. The Lightning version does not over the flexibility of a BT connection, so one is more limited in placing it in a good position. But maybe you can move the smartphone further to the windscreen / front to make get better accuracy. Chip-wise, both should not be too different.

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Tripper
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Re: Best GPS Sensor for iOS

Post by Tripper »

I was always very happy with the 160's performance, but it won't stay on for more than a few seconds now even when it's plugged in.

The 160 worked perfectly in the glove box, in the centre console, and in the passenger footwell. The BadElf is plugged into my phone on the dashboard. I don't think that can be a worse position but in any case I can't really move it.

So I've gone with the Vbox Sport. First track day with it is on Monday, I'll let you know how it goes.
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Harry
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Re: Best GPS Sensor for iOS

Post by Harry »

Tripper wrote: Fri Nov 05, 2021 9:55 pm So I've gone with the Vbox Sport. First track day with it is on Monday, I'll let you know how it goes.
Please use an external antenna, it is making a huge difference!
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Re: Best GPS Sensor for iOS

Post by Tripper »

Two thumbs up for the Vbox sport. It worked flawlessly, no connection issues, and the battery lasted all day.

It's worth bearing in mind that at this early stage I would have spoken in glowing terms about the Dual 160 since it took a while for the reliability issues to emerge.

Attached is a screenshot of tracks on a corner of Silverstone: red line is from the Dual 160 in February, the green line is from the Vbox yesterday. This might be luck/favourable atmospheric conditions but the Vbox seems to be more accurate.
vbox.jpg
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Harry
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Re: Best GPS Sensor for iOS

Post by Harry »

The effect you see is the so called GPS drift:
GPS drift is most often caused by reflections or shadowing on an image. It can also be due to atmospheric conditions which alter throughout the day, being most pronounced in the early morning or late afternoon. Due to the sun’s low angle relative to the atmosphere, there is more atmospheric interference.
It changes slowly and produces a - for a lap almost constant - offset. Direction plus distance. In case you are lucky, it is small. Only GPSes using ground based augmentation systems (GBAS) are able to compensate this. This works by sampling positions for a well known position near the track. The difference is what needs to be compensated. Neither the 160 nor the VBOX are in this league. So it happens.

Actually both of your recordings are great in terms of relative position.

LapTimer has an experimental feature that snaps a lap's recording to the track definition. You can try it: make sure the track set is loaded; select the (red) lap in Lap List; follow Data Recordings / Fixes and tap the second icon in the bottom. Select "Remove GPS Drift". This will analyze what drift produces the best match between line recorded and POIs defined. It will compensate that drift.

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Fredman6
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Re: Best GPS Sensor for iOS

Post by Fredman6 »

Tripper wrote: Tue Nov 09, 2021 2:35 pm Two thumbs up for the Vbox sport. It worked flawlessly, no connection issues, and the battery lasted all day.

It's worth bearing in mind that at this early stage I would have spoken in glowing terms about the Dual 160 since it took a while for the reliability issues to emerge.

Attached is a screenshot of tracks on a corner of Silverstone: red line is from the Dual 160 in February, the green line is from the Vbox yesterday. This might be luck/favourable atmospheric conditions but the Vbox seems to be more accurate.

vbox.jpg
Thank you for the feedback. Will look into VBOX for next season.
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