Rob's Rants

In my initial review of the T-Mobile Dash 3G, I made some comments about the GPS functionality. Specifically, I complained about HTCs power management and the sensitivity of the receiver. I wanted to take a closer look at the GPS after a few weeks of use.

Power Management

I still think HTC’s power management scheme is a problem. Essentially, when the phone puts the screen to sleep it shuts down all other functions except the basic processor and the cellular data service. This includes the GPS and Wi-Fi. The problem is the conflict this causes with modern location-based services like Google Latitude. What this effectively means is that you can’t use Latitude or track your movement with something like GPSed unless you set the power so that the screen doesn’t power down during use. What really annoys me is that many GPS applications have a setting that is supposed to prevent the screen from turning off, but many don’t seem to work on this phone. What’s even worse, is that locking the screen overrides the power settings! So even if you set the screen to not turn off, if you lock it, it will turn off anyway! That’s simply wrong. Try carrying the phone in a pocket with Latitude enabled and without locking it. Just see who you ass-dial when you sit down.

Multi-Program Use of the GPS Works

On a positive note, a common criticism of HTC and other GPS implementations is that most programs access the GPS output directly. Which means only one program can access the GPS at a time. So it’s not possible to use a navigation program at the same time as a tracking program. There are several ways that people have overcome this, including a popular software program called GPSGate, which acts like a GPS data server that several programs can access at once.

It appears that this implementation has solved the problem without the need for 3rd party software. Today I was able to simultaneously use my Garmin navigation program at the same time as GPSed to record my route. Both programs worked flawlessly. This is a huge convenience and helps offset the power management issues in my mind. I don’t know that it totally offsets the power issue, but it helps. No special configuration was required to make this work — the GPS receiver appears on COM 4 in this implementation. Just set your program to find that port and everything should work fine.

Sensitivity and Lock Time

[Update - 7/31/09 -- Because I always reserve the right to be wrong -- there is a quick note posted by an xda-developers member on his blog about a better experience with the GPS lock time than I report (see http://bupahs.blogspot.com/2009/07/htc-dash-3g.html). As with all things on the internet, I encourage you to evaluate the different experiences and draw your own conclusions. Hell, maybe even go to a T-Mobile store and ask them to fire one up for you and see how the GPS works for yourself.]

This is another issue I’m having. When the GPS is first enabled it needs a perfect view of the sky in order to obtain a satellite lock. If you don’t have a clear view, expect minutes before the GPS locks, And this isn’t affected by whether or not the HTC Quick GPS program is used. In addition, the GPS receiver seems to lose signal more than any other I’ve used before. I even lost signal in a completely open part of the Mass Pike (I-90) around Newton and it took 2 minutes to get it back.

Conclusion

On balance, the GPS seems OK, as long as you can get a signal. Of all the issues, I think the lock time and signal capture are the ones that concern me the most. I can find a way to carry the phone so that I don’t need to lock the screen. But the GPS doesn’t do any good unless it works when you need directions. And a GPS that can’t get a signal might as well be a brick.

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Related posts:

1. T-Mobile Dash 3G — Another Short GPS Update
2. Dash 3G GPS Help?
3. I’ve Officially Given Up on the Dash 3G GPS
4. T-Mobile Dash 3G — First Impressions
5. T-Mobile Dash 3G – Ongoing Update #1