Poor GPS performance

R

Rifleman

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Feb 16, 2016
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Location
Nottingham
Country
United Kingdom
Dash Cam
mini0806, mini0801,Viofo A119
I have posted comments about poor performance of the A119 GPS unit in another topic. I was hoping for a reply from Viofo but sadly they have ignored the issue so far 🙁.

Is anyone else having GPS issues ?

If it might be a GPS receiver problem and not something that can be fixed in firmware I need to know very soon so that I can return the A119 for a refund as in my opinion the GPS receiver is not fit for purpose.

Here's my original fault report:-

"The GPS logger is very unstable, quick to get first fix but far too many drop outs while driving. For instance on one 30min journey the GPS data was only visible on the recorded footage for approx. 15 mins with multiple gaps. The track shown in Dashcam viewer is wildly erratic, in the same journey the track only matched with the actual route taken for about 2 minutes, rest of the time is was offset by anything up to 200-300m when working, just straight lines between two points in places because of drop out.

I compared this with footage from the rear view mini801 with GPS ( the A119 replaced this, it was front camera but moved it to rear ) over the same period. The mini801 GPS was much slower to get initial lock BUT once locked it stayed locked throughout the journey. Viewing footage from this in Registrator Viewer showed the GPS data to be rock solid, matched up perfectly with the actual route to with just a few meters.

Can something be done in the firmware to correct this very poor GPS performance or is it more likely to be the GPS receiver that's at fault ?"

By the way, I've swapped the A119 with the mini801. 801 is now returned to the front windscreen with GPS working fine. A119 is now mounted on back ( vertical ) window on non-GPS mount. This mount is a much looser fit than the GPS mount and I'm experiencing a fair bit of vibration between the camera and the mount. I am looking at ways of stopping this movement with wedges, sticky pads etc. , has anyone else experienced this ?
 
I have sent PM to you, we will do further checking for this issue.
 
I just noticed today that my non GPS mount (pre production) is a little loose. I figured it was from the Texas heat, and I was planning on applying a thin layer of adhesive felt to the mount itself, not the camera. The kind I have is actually made by Toyota to fix squeaks and rattles in car interiors. It's only about 1mm thick, not the 5mm stuff you get at an arts n crafts store.

I had to do something similar on both of a118 cameras which use a similar mount, and Street guardian provides a similar thing to stick on their sg9665 mount (sorry if I got the model wrong - the one that uses the same chassis as the a118) to prevent the rattling that happens as the mount stretches a tiny bit after being mounted for a few weeks or months. Maybe @viofo could stay including something similar for the non gps mount... Hopefully it would adhere to the honeycomb looking surface of the mount ok.
 
After getting a response from Viofo on this I re-hashed my camera set up and performed another test journey.
I re-mounted the A119 and the mini801 side by side on the windshield and set off.

On inspection of the recorded footage I was surprised to see that the GPS track from the A119 was much more stable and accurate than my previous test.

There are slight differences in the recorded GPS tracks between the A119 and the mini801 but far less significance than the previous test. Overall the accuracy of the mini801 GPS looks slightly more accurate, the route plotted on the map in Dashcam Viewer was nearer the actual road rather than being offset from it. There also seems to be a tiny bit of lag on the A119 plot ( track overshoots bends when turning sharp corners ) but not really enough to bother about.

Some of the inaccuracy can be put down to Dashcam Viewer. I compared the same clip from the 801 in Dashcam Viewer and Registrator and Registrator was definitely the most accurate it terms of the plotted track synchronising with the road on the map and again it introduced a small amount of overshoot on sharp bends.

My conclusion is that the A119 GPS unit seems to have settled down now and it's performance is now quite acceptable.

I have two theories on why my initial test gave such poor results:-
1) Temperature. Original test was over a period of a week when the outdoor temperature was 30-32degC, new test was carried out when temperature was 18degC. The test car does not have air-con.
2) Could have been a problem with the GPS pin contacts. I removed and replaced the A119 a number of times between the two tests. Maybe they didn't seat correctly on the first test.

I have sent some recorded footage to Viofo for them to inspect and I'll keep a close eye on the GPS performance. I'll report back if there are any further issues.
Sorry if I spooked anyone with the initial reports...
 
jokiin said:
were your initial tests also with the 0801 in place?
Click to expand...
Original test was done with the A119 mounted on the front windshield, mini801 mounted on the back window. I compared the output of the two GPS units over the same journeys at the same time. That's why I was so shocked at how inaccurate the A119 appeared to be using the mini801 in direct comparison...

It's also the reason I re-jigged the second test so that both cameras were side by side.
 
Side by side the performance can suffer as the other camera can impact the GPS reception, accuracy can be reported differently also due to software interpretation variations as each uses a different format

May not be related at all but something to keep in mind
 
brewsky said: ↑
My A119 will not retain my Time stamp. It always reverts to a time 4 hours ahead of my time. I have set the time manually and also on the screen that allows you to adjust the time from GMT. When I exit the menu, it always reverts back to 4 hours ahead. Bug?
Also, GPS is very slow to update. I can accelerate from 0 to 45 in 15 seconds, yet the speed indicator takes about 30 seconds or longer to "catch up" with my actual speed. When I stopped the car for 60 seconds to get out and get the mail, the GPS speed never went lower than 15km/hr, even when the car was stopped.
Click to expand...

Posted this in the bug report thread but thought I'd repeat it here as it's a continuation of previous GPS problems...

I've just reviewed the latest footage from my A119 and can confirm the GPS slow update mentioned by brewsky.
For example, approaching traffic lights at a steady 25mph the speed shown in the recorded footage is 40kph. Lights change to red and car comes to a stop. The displayed kph reduces steadily by 1 or 2 kph per 1 second of recorded footage so display does not show zero until 28s after coming to a stop. The last 3digits of each of the displayed GPS coordinates during this period can be seen to vary erratically
Similarly there is a lag when accelerating away from the lights, there is a long delay for the displayed speed to catch up with actual speed. Only when a constant speed is reached and maintained for quite a while does the displayed speed catch up and show the correct speed.

To my mind this a serious defect in the A119s GPS, it could be critical if the footage is used for evidence in the event of an accident.

@viofo Can anything be done about this ?
 
Can you check if the GPS speed showing correctly on the DASHCAM viewer player?
The firmware read the GPS data from movie file, can not update the data on time.

For the 0801, the GPS data is stored separately, while palyback the files it can load the GPS file as subtitles, I thought this make the difference.
 
Thanks for the swift reply Viofo. I'll check that out this evening and get back to you.
 
@viofo Hi Viofo.

It seems that Dashcam Viewer lags behind the actual speed seen in the video footage and the Speed displayed by the A119 bottom left in the video lags further behind Dashcam Viewer.
So when you see the car comes to a stop Dashcam Viewer takes a few seconds to reduce to Zero speed but the speed shown in the video takes even longer to reduce to zero.
Likewise when accelerating from a stop Dashcam Viewer lags the actual speed and again the speed in the video lags behind Dashcam Viewer.
The faster the decleration/acceleration the longer the A119 speed takes to catch up with reality.

I keep losing the video footage from which I'm reporting this problems because the card keeps formatting when I replace it back in the camera so in future the first thing I will do when I view the footage is to copy the SD card contents to the computer's HD. In the meantime I've look back at some old footage which I did keep and I've uploaded a clip to dropbox. Take a look at around 19:02:25 onward and you will see the car come to a stop and the speed lag in Dashcam viewer and the A119. In this example it's a fairly short lag compared with others I have seen but it gives you an idea of what I'm experiencing...

https://www.dropbox.com/s/zu2tkwxkii0w9p6/2016_0727_190024_012.MP4?dl=0
 
Received my A119 today.
Loaded the latest beta firmware.
Installed Transcend 64GB 633x SD Card.
Went for a short test drive.
Initial observations.

1. The GPS data is very accurate. Also speed information, as viewed in Dashcam Viewer. No lag when accelerating or stopping.
2. I notice little to no difference between the 1440 and 1080 video resolution.
3. The file sizes for the 1440 and 1080 are very close to being the same. The bit rates for both are 96 kbp, and the data rates are also very close.
4. I have a LOT of dashboard glare from a GPS and Radar Detector on the dash, and I'm in dire need of a CPL Filter.

Overall, very pleased.
I used a temporary installation using Velcro, until the Vico Power Plus and some Fuse Taps arrive. There was obviously quite a bit of vibration, even with that the videos were stunning.

RodeoGeorge
 
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