Ublox Dead Reckoning GPS - Page 4

spaceskater · 02-02-2006, 06:39 PM

So anyone roadtested it yet? Mine will arive tomorrow...!! but i still need the rest of the circut stuff...
Jcdillin any updates? did you road test it? I'm just exited! not trying to be annoying...!

nl4jy · 02-03-2006, 09:15 AM

Quote: Originally Posted by spaceskater

So anyone roadtested it yet? Mine will arive tomorrow...!! but i still need the rest of the circut stuff...
Jcdillin any updates? did you road test it? I'm just exited! not trying to be annoying...!

Well, Laidback did his own and it works perfectly for him... JC is the only one that's doing the boards for others. Patience is the key... Look at me, I waited nearly a whole year already for this to become a reality.

aoLhaTer · 02-10-2006, 12:48 PM

I GOT IT INSTALLED, WOOT

Finally decided to install the GPS and rip up my car once again to get to the speed signal. Gave it a small road test and it performed admirably. Couldnt find any tunnels or parking garages to lose complete signal but I drove in areas I knew I lost signal with my old GPS.
Besides the dead reckoning on this reciever its normal functioning GPS seems to do awesome as well. My old GPS (Garmin 15L) would pick up about 5-7 sats where I am and now the Ublox picks up 7-10

Now I just wish they made one of their 8hz models with DR

jcdillin · 02-10-2006, 12:57 PM

awesome to hear, mine is going in saturday after I get back from the dealership for service. Figure i'll wait for the warranty service before I start splicing into ecu wires.

aoLhaTer · 02-10-2006, 01:18 PM

Sounds like a sound idea

I suppose I was lucky and had a speed signal available behind my stock head unit since it has speed controlled volume. Still meant I had to completely disassemble the dash and then disassemble the rest of the car to run the single wire.

I ended up soldering directly to the board instead of using that connector btw jc

Interestingly I found that when using iGuidance and the signal was lost using the Ublox GPS, the program would crash. It happened twice and they were both in areas I would usually lose signal. My only hypothesis is that iGuidance doesnt know how to handle the situation when signal is lost but directional data is still being sent so it crashes.
I tried with CoPilot after that and it did not crash and ocassionally the sat meter would go to red but I would still be moving on the map

jcdillin · 02-10-2006, 02:01 PM

shoot, my radio has that pin but the wire is missing from the harness, only thing I can think of is that the speed signal is on the CAN-bus

Sorry bout that, if you still want it I have it ready just havent had a chance to post it.

thats strange, i'll have to try it out on mine, I use mapmonkey so we'll see how it works. What version of iguidance was that?

inferno2469 · 02-10-2006, 02:10 PM

would this work better?
http://www.u-blox.com/news/conrad.html

jcdillin · 02-10-2006, 03:03 PM

Not really, because that unit does not do dead reckoning like we are going for. If I wanted something like that then I would have stuck with my garmin 15L.

inferno2469 · 02-10-2006, 03:28 PM

sorry, my bad.

aoLhaTer · 02-11-2006, 04:41 PM

Well my success was short lived

Im now getting erratic GPS positions when in DR
I made a log using u-center and what I noticed that in the statistics view none of the EKF gyro data is showing any values. Dont know if its supposed to or not but something is not right either way

I emailed Ublox asking if values should be there and also sent my log

Argh

mrbean_phillip · 02-16-2006, 12:20 PM

Hi Cherrybomb,
There are 2 versions, the DR one which update it's output at 1Hz, and the non-DR unit which does so at 4Hz.

The 40Hz you are referring to is for internal calculations in the DR unit.

nl4jy · 02-17-2006, 09:40 AM

Just wanted to know if JC installed and test it yet.

jcdillin · 02-17-2006, 04:53 PM

havent made it to the car yet, having the same problem gyro problem as aolhater so i've been working with him to try to resolve it.

spaceskater · 02-24-2006, 05:18 PM

Any updates on this? I have most of the parts now so i could start putting it together. Is there anyone that has this thing working with no problems?

ehiebert · 02-24-2006, 06:22 PM

Hey all... newbie member to this particular forum, but not new to GPS.

Anyways, we used the ublox module with DR/Gyro input on a project we did for the local transit authority to provide them with an AVL system. For prototyping we tried to used the speed pulse signal from the transmission of a 1992 Ford Explorer. Problem with that was two fold..... no direction indication for forward/reverse, and the pulse was more of a sine wave with very little magnitude at slow speeds. Consequently, the speed tick input probably did more harm to position integrity than good.

So I deveised another solution which worked perfectly. I rigged an optical quadrature encoder (200 PPR) to one of the rear wheel hubs, and then used one of the phases for a speed signal, and the phase differential to provide a F/R input. This required some interfacing... that was done on the same carrier board we used for the UBLOX... which was a PIC 16F4550 based microcontroller board which I did.

After all of this, we could disconnect the antenna and drive a few circuits of an underground mall parking garage. At the end we finished with a position error of about 5m. That was after many turns and probably 2 km of tavel with no antenna. Repeatability with combined satellite lock and inertial signal was in the 1 m range. It was quite impressive...

I have the schematic for the carrier board if anyone is interested. I could also supply the firmware for the PIC. I had combined this board with some opto-isolated I/O and relays for random stuff. The whole thing then got wrapped into a custom USB protocol for reading NMEA sentences, reading inputs and setting outputs.

Now I'll compare this to a SiRF-III BU-353 GPS mouse..... the SiRF-III is an incredible value for its ~$100 price range. In drive testing it is just as accurate as the UBLOX without DR-enabled, with repeatability coming in at an average of 2-3m. Repeatability testing was done using software (i wrote the test software also) which would trigger a light at a trigger waypoint. Then a video camera is setup to watch the vehicle cross the marked waypoint and record when the light comes on. Since standard update rate of the UBLOX and SiRF is on 1 second boundary we used time division, linear extrapolation as a resolution enhhancement algorithm. This provided us with real-time estimated position updates at 100 Hz frequency. From this testing we noticed that the SiRF and the UBLOX were almost identical in absolute poisition accuracy. When the speed sensor input was added to the UBLOX it bacame a much more accurate interface. However, for the money the SiRF is an excellent device.

Eldon.
'94 Explorer
Intel MiniITX MB
8"TFT
Linux integrated application software (protoyping... and un-named as yet)