Syncing video and GPS-data

[Hellis 0]

Been doing some experiments with GPS logging and videoing and i think i found a way to synchronize them quite well.
I cant find the thread right now but there was a thread somewhere about how you would find your exit on GPS data when doing wingsuit jumps.

I made a test video where i synchronized the video and GPS without using "obvious points" (sudden starts or stops, up or down movements).

I used my cellphones (SonyEricsson P1i) GPS and a free GPS-logging software. The phones GPS is a dongle that uses bluetooth to send the information to the phone.
And since i have a screen (compared to other GPSloggers) i can video the cellphone screen for a few seconds which shows me GPS-time.
This GPS-time is also the same data i get from the logger when i download it all to my computer.
So all i need to do is look at the video what GPS-time it is and sync the data with it.
I do think this method can be used with other phones and other GPS-recivers aswell as long as they are bluetooth GPS and the phones support Java software.

I uploaded the video for you guys to see, but keep in mind this is my first ever video.
I bought the editing software 2 days ago and do not have any mad skilzzz
I completly messed up the video, and by the time i realised it i didnt want to redo everything.
So my ~450 MB file ended up as a 20 MB file
Anyways enjoy!
http://www.vholdr.com/node/66468

The GPS-reciver is a RoyalTek RBT-2100LP http://www.semsons.com/robtgpsxrsii.html
20 channel GPS

The software i use is vlkGPS http://vlkgps.sourceforge.net/
This software supports up to 12 channels.
Its unlikely that you get singnal from more than 12 satellites anyway so it does not bother me.

And the phone is a prehistoric SE P1i as i mentioned, but since the software is Java *any* phone should do.

[Hellis 0]

Heres the thread i was thinking of.
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3678928

[LouDiamond 1]

What altitude did you do this at? Typically phone based GPS signals drop off around 10K +/- due to the loss of communication with the cell towers. The GPS data collected ,even while on the ground sometimes, tends to be grossly off location wise when derived by cell phone in some areas. In general, I would not put a lot of faith in the accuracy of cell phone derived GPS coordinates.

Using a dedicated GPS receiver is a better idea if the accuracy is important to you(which I am assuming it is and thats why you're using a GPS in the first place). Another way you can do this is by ensuring your camera's clock/time matches the time on your GPS receiver before going up( ie: use the GPS derived time). The GPS data will have time stamps that you can match to the cameras time. Likewise, most loggers have a function where you can start and stop the logging by pushing a button. Filming this action will also allow you to synch the two.

Klaus(Paralog) has put together a template to do all of this so that you real time GPS data is displayed on the video as the video plays (see attached pic). Check out the Paralog website to read the write ups on how to do it.

PS: Klaus also played around with blue tooth to a phone and the data was not the best and was more trouble than it was worth if I remember correctly.

Picture: CLICK ME

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[Hellis 0]

Well as the video shows, i drove the car on the ground.
EDIT: Oh.. i just noticed the vholdr webpage is down.

I know cellphone GPS can be off, but even though i got this GPS-reciver with the phone i dont think its of the same low quality as built in ones.
When i look at the reception of the GPS i usually get full reception on 8-10 satellites when im outside.
Indoor right now Sitting by my computer and having the GPS ~6 feet from a window i get data from 7 satellites.
satellites no. 8, 2, 4, 10, 13, 23 and 7 if you want to know
the reception is bad, but the phone can easily see where i am and notice if i move the GPS in the room.

This software does not rely any phonereception as far as i know. It does not need to use GPRS to download any maps.
This software is only reciving what the GPS sends.
See attached picture below.
http://www.hellis.me/IMG_9450.JPG
I will try tomorrow to remove the simcard and try use the GPS, if that works, that should mean operating in the air should work.

When the snow melts i will test the GPS in the air and get back with the results.

[Hellis 0]

The phone didnt start without Simcard, and i could not force it to disconnect from the network.

I think i have seen a application for the phone that allows bluetooth in flight mode, but i cant find it.