Trackaroo Trackmaster

A question that comes up a lot when using an external bluetooth GPS with Trackmaster is whether to use 5 Hz or 10 Hz GPS. With Trackmaster it's a misconception that 10 Hz is better than 5 Hz. In fact, it can be worse. If your device does not have a powerful processor that can handle the 10 Hz rate, you will have data logging issues. Data will be dropped or delayed. Only the latest devices with very powerful processors (1GHz+) can handle the higher rate. Also keep in mind that you are generating much more data with 10 Hz. So post-processing the data will take longer for analysis and export.

10 Hz is NOT more accurate than 5 Hz. Trackmaster interpolates data. This allows it to be very accurate. Some people attempt an accuracy calculation based on the refresh rate .2 secs (5Hz) and .1 secs (10Hz). Because Trackmaster interpolates data, this calculation is incorrect.

Unless you have a specific need for 10 Hz and have a powerful device, I recommend using a 5 Hz GPS over 10 Hz.

If you already have a 10 Hz GPS and are experiencing issues, you may be able to reprogram the GPS for a lower rate. The QStarz GPS allows you to do this.

Jeff

just bought a qstarz 818xt. but i cant find the guide to switch it to 5hz. it has a manual switch but its only 1hz or 10 hz..

i think i saw some place here ????

I've been using Trackmaster with a bluetooth GPS for some time at 10Hz, thinking more readings = more accuracy. I was assuming that you would be averaging (or filtering) the readings since there seems to be some variation from one reading to the next. (For example, look at the readings of a stationary GPS unit.)

Anyway, the unit I have is a Wintec G-Rays I. It supports 10 Hz, 4 Hz, 2 Hz, and 1 Hz (no 5 Hz). Do you recommend that I use 4 Hz?

Another question, which might be related: I'd like to run the Torque app at the same time as Trackmaster with an external bluetooth GPS? Torque will use the internal GPS as well as bluetooth to get data from a ODBII adapter. The phone is a Droid X.

I just used Trackmaster yesterday for the 1st time at PIR in Oregon. I'm running it on a Droid X. What fun.

I have some questions about the quality of the data and whether I should invest in a Bluetooth GPS receiver.

The data in Excel shows 106 readings over the 1.96 mile track. Approx every 1 second. With 5,280 feet to a mile and speeds ranging from high 30mph to over 130mph several times per lap, does this mean I'm gathering a data point every 114 feet average. BTW, using Google Earth, my racing 'line' is made up of straight sections that don't always overlap the track map. Is this due to the above sampling rate, or something to do with satellites?

If I use a 5hz or 10hz GPS receiver, how much more clear will the data be? How does a 5 or 10 rate compare to the native Droid X GPS sampling?

Thanks in advance for the clarification - great product. I'm looking forward to using this to improve my driving and setup.

Dan J
Portland, Or

My guess it has something to do with the sampling rate and location of your phone.
When I switched to using a BT GPS at 5hz my line was on track rather than showing me off most of the time.
The BT GPS was a good investment.
I tape the GPS to my sunvisor and leave my phone in my pocket.

I see how to set the Update Rate, but I don't see how to configure to 5hz when the device is on the 10hz position. How do I do that?

It appears that you can set it after you turn the unit on and plug it into a computer and run the program, but you need to do this each time you turn it on, which means that you have to have a computer available whenever you use it.

If I could reprogram the 1hz switch to work at 5hz, and have it stay that way through a power cycle of the unit, I would be happy. The messages above imply that this can be done, but I don't see how.

Thanks. -bg

Thanks a bunch, Dimitry! I followed your instructions to the letter and it worked! -bg

Just to clarify, I'm intending to use this while go karting. It's a 900m circuit as shown in one of the pictures: here. I did a very unscientific test just walking around in a car park, and I didn't really notice any appreciable difference between the two modes I mentioned. If anything, the BT GPS Service was reporting slightly higher accuracy ratings for 10Hz, but it was very marginal. I have the Samsung Galaxy SII (i.e. dual-core 1Ghz), so I don't think processing power/storage should be much of an issue...

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I think it's also notable that the DGPS (Differential GPS) system on the Qstarz 818XT doesn't function at the 10 Hz rate but does work at the 5 Hz rate. Even though I have one of the more powerful phones on the market, I would think that would be the deciding factor between one rate or another if you have the option to choose.[/quote]

I tried enabling DGPS (SBAS option) on my 818XT at 5Hz but it would not save the setting. When reconnected to the PC and checked in GPS view, it shows as being disabled. Is there a reason I can't save this setting to the unit?