Thread: TomTom How To (PocketPC Emulator)

Nice, thanks for sharing the video clip. However, I don't see the smooth, fluid movement of 3D map I'm used to on my wife's old TomTom GO. TTG refreshes screen 4 times per second, but the map in the above video seems to jump once per second only.

yes, as it does on the pocketpc. the ppc version has never been as smooth as the tt go/palm version. this is due to tomtom not coding it correctly for the ppc!

are you sure it's not because the tomtom go has a 4hz gps module and you are using a 1hz gps module? Maybe tomtom is coded to react to the gps update rate and with a 4hz input will do it.

As far as I know TTG has just a plain regular 1Hz receiver, but the 4Hz screen refresh is something the software does. The software actually does one more very neat trick: it anticipates where you will be in about a second and it displays this "predicted" position. This way it masks the one second natural "delay" we see in other navigation solutions. The resulting effect is that it appears the GPS arrow shows EXACTLY where you are even when moving. (In other software you would normally see a one or two second lag.) This is very neat (even though I don't like TTG for other reasons).

I've always been annoyed at the speed of the ppc version of tomtom. nothing to do with the feed speed afaik, it's to do with how tomtom impleenmted it. the tracking you speak of is also done on the ppc. it's no more than a linear alpha-beta tracker (here's my vector, what's my next position based on the last vector?). alpha beta trackers are crappy on curves. u need a kalman filter for that and they're too expensive. saying that, road data + route data + alpha beta filter can tell you where you're heading, but without a route, you'll find it can be left or right, and this is why when going around curves without planned routes, the gps always messes up.

its not that hard to do. it's just using interpolation. that is how i wanted our GPS software to be done by adding an intermediate inbetween the gps and the software to manually provide gps coords but D3 can only refresh at 1hz anyway.

Sama, the uBlox gps has basic kalman filtering to take gyro and speed pulse data and fill in the gaps when gps signal is low. unfortunately the chips they use at the moment cannot handle outputting at more than 1hz even though the inertial calcs are done at 40hz. I did try and get a standalone kalman/2D inertial system developed at work but we didnt have any suitable undergrads and tbh it would probably be a masters/phd level project. Saying that someone on here could probably do it pretty easily due to the vested interest.

edit: combine that with a 4+hz gps reciever and you would have a very nice gps system.

agreed. i do know someone that works on embedded systems in sussex uni. he's a post doc and developing for the mod passive naigation. perhaps i'll pick his brains for some code sometime. if only there was open source routing library I'd write my own mapping app. anyone up for the challange?

Originally Posted by sama

agreed. i do know someone that works on embedded systems in sussex uni. he's a post doc and developing for the mod passive naigation. perhaps i'll pick his brains for some code sometime. if only there was open source routing library I'd write my own mapping app. anyone up for the challange?

I'd love to be able to help........... but I can't even figure out how to get TomTom installed on my lappy