2 replies to this topic

[allen]

I have written an Android Starting Line App but find the GPS accuracy on these non WAAS GPS units in my tablet and phone less then what I am getting on stand alone GPS units. I am seeing 16-32 ft accuracy, typically 20 feet. For a start, that gives a couple of boat lengths in uncertainty. My Garmins are giving more like 10 feet and realistically I am thinking that is about all I should shoot for as the line can move with changes in wind and current afterall. So I am looking at Bluetooth GPS pucks like this one My link.

What has me concerned is that there seems to be two markets for these things. 1) Very fast things like race cars. 2) People who want to know where they took a photo on their vacation.

I am a very slow thing that wants to know exactly where I am and how fast (slow) I am going. A side point. GPS speed based on difference in distance might work if you are going 100HPH or have a long averaging time but not if you are going 4 knots. The best speed accuracy is done from Doppler shift from the satellite carriers. That is how all the GPS units give speed. It is important that speed be done that way so that has to be a spec. I want a unit that gives both excellent location and speed accuracy.

I am generally inclined to go with a unit that is made for the market I am in but there basically are none (see above). Of course, there are units like the ProStart, but that is distance only and what I have written goes way beyond that. Nothing against the ProStart, but even Velocitek says it is made for smaller boats. I hope to test the new Rock Box but have not done that yet so can't tell if that would be better than what I have written. It certainly would have a better display and that is a huge issue.

I am interested in peoples experience with the different Bluetooth GPS pucks on the market and interfacing them with Android phones and tablets.

Allen

[hyerstay]

I use iRegatta on my iPhone in a Magellan case that has its own GPS chip, and it seems pretty accurate. However, i would be interested in a puck solution, and this new GPS/GLONASS unit from Garmin looks awesome:

$129: https://buy.garmin.c...p.do?pID=109826

$99: https://buy.garmin.c...p.do?pID=109827

I think the hardware is the same on those, and the included accessories and some sort of Garmin Pilot trial are the only differences.

jason

[allen]

I use iRegatta on my iPhone in a Magellan case that has its own GPS chip, and it seems pretty accurate. However, i would be interested in a puck solution, and this new GPS/GLONASS unit from Garmin looks awesome:

$129: https://buy.garmin.c...p.do?pID=109826

$99: https://buy.garmin.c...p.do?pID=109827

I think the hardware is the same on those, and the included accessories and some sort of Garmin Pilot trial are the only differences.

jason

There are a couple of footnotes in the manual for the Qstarz unit. "Note3: Under 10Hz fix update rate, DGPS function will be disabled". and Speed accuracy: "Without aid: 0.1m/s, DGPS (WAAS, ENGOS, MSAS): 0.05m/s" So basically the speed accuracy goes from .1kt to .2kt when you go to 10Hz update. There is no speed accuracy listed for the Garmin unit and there is no manual so this is something to watch out for.

I tried iRegatta for starts but it didn't work out for a number of reasons which I wrote about on L-36.com My link. BCVRacer is another one I tried but basically if you are using speed, heading, and location to tell you when you are going to get to the line, you are too late. You need something that gives useful information during the entire pre-start period most of which you are not heading toward the line.


Allen