Notices

I need an application for precise checkpoint distance measurement during 4x4 rally events. It's an essential roadbook support. There is no such application on any other platform (it's a very niche thing) besides maybe GPSAuto on Windows Mobile. People have hardware devices specifically for this functionality, hardwired to engines so that they are a ultra-precise (without the use of GPS), but these are really expensive.



The name of the app would be "Itinerer Support" or something like that.

What it needs is a simple GPS distance indicator, which displays the overall distance at the top (small font), and a single "checkpoint" distance at the bottom (massive font). Accuracy of both should be to within one meter.

The single checkpoint distance should be reset to zero meters whenever I tap its display (so it starts counting from zero immediately - sometimes the distance between checkpoints is 50 meters, so any delay would cause issues). There needs to be haptic feedback that confirms the action. Tapping the large checkpoint distance display is essential, a small button is really easy to miss during a rally. There should be no confirmation dialogue.

The small overall distance indicator is not interactive, but it would be nice to have the standard main menu item to reset the overall distance, which resets both counters and requires confirmation. Overall distance is just that - overall distance, resetting checkpoint distance doesn't affect it, it just measures the distance from the last global reset.

There should be a "Tap to START!" button in the place of the checkpoint distance when you start the app and whenever you reset the overall distance using the main menu. This is useful, because I have to wait for the GPS fix before starting to measure the distance and the GPS position is sometimes "floating" - at a complete standstill I would already get fake distance, so this would alleviate the issue at least at the very beginning of the rally.

Additionaly, there could be a timer, indicating the time from the last overall reset (not checkpoint reset), next to the overall distance indicator.

For extra points there could be a nice large green icon (just a rectangle, nothing fancy) to indicate "detailed" GPS lock, orange for "coarse" GPS lock and red for no lock, between the counters, somewhere in the middle.

Future development ideas:
- Add switching between Imperial and Metric units via the main menu
- Add "Pause/Continue" functionality via the main menu
- Current speed, Maximum speed, Average speed indicators via separate menu
- Black box-like recording of forces working on the car using the accelerometer (something like AccDisplay?)
- Add "End Event" functionality via the main menu to reset and record the time, distance, avg. speed, max. speed, forces to a file/graph/html file.
- Speed limit setup with audible warning
- Side and front/back vehicle tilt setup (accelerometer) with audible warning during crawling speed so as not to tip the vehicle over.

That's a showstopper right there - GPS won't give you that fine accuracy without some sort of augmentation (WAAS/EGNOS/differential GPS, and even then it's achievable but not guaranteed), and AFAIK there's no way to use those on Maemo devices :-(

My Mio P550 Windows Mobile 5 device with a lock on 8-10 satellites is accurate to within one meter judging from the last rally, the GPS position didn't float at all during a complete standstill. Unfortunately that device got destroyed during the rally, otherwise I wouldn't be asking for such an app for Maemo. Are you saying the GPS in my N900 is worse?

Ouch :-(

Probably.. the P550 has a SiRF III chip which is generally considered a lot better than any of TI's offerings. The SiRF does support WAAS, but no clue whether the P550's OS enables/uses it. The TI navilink specs don't mention anything like that.

BTW, there are some measurements of the N900's built-in GPS accuracy here.

You may be able to get away with using a better external GPS receiver, but you may have to speak to it directly instead of via liblocation.

The accuracy should be good enough according to those measurements. I can get away with less accuracy than before, it's just support, not a life line

No takers then, I suppose...?