(img adapted from Cyphol's original)

We here at WMExperts write this with due amount of trepidation, humility, and a willingness to admit we are completely in over our heads on the technical aspects of what we're about to discuss, but here goes:

It appears that the Touch Diamond and the Touch Pro have some issues with regard to GPS. Namely -- many users are reporting a significant lag -- not in satellite acquisition, but in the actual reporting of your position as you move. On these devices, GPS often (but not always) seem to be several seconds behind on reporting your position. While a lag of several seconds (or more) doesn't sound like much, it is pretty much a deal-breaker when you're attempting to use GPS for driving or biking directions.

Missed turns aren't fun, so read on for more.

Folks over at XDA-Developers are reporting/discussing GPS lag issues with both the HTC Touch Diamond and HTC Touch Pro. Additionally, at PPCGeeks we read that certain software on the CDMA Touch Diamond on Sprint sometimes lags. Here's what the the situation looks like right now: GPS lags of up to several seconds are being reported for different people, across several different GPS apps, and in different parts of the world.

As we've said before and at-length here at WMExperts, these sorts of issues are often very difficult to pin down as they lie at the intersection of different kinds of chip hardware, processing power, drivers, software, antennae, and the like.  In fact, all of the above have been posited and tested as possible causes. Adding insult to diagnostic injury, some report fixes based on radio or ROM updates while others don't.

Based on some of the discussion over at XDA, it does look like HTC may be aware of a problem and is looking into it.

Both the Diamond and the Touch Pro utilize the Qualcomm MSM7201a chipset, leading us to worry just a teensy little bit that we're looking at a redux of that other complicated issue involving HTC, Qualcomm, software, drivers, and graphical performance. We're not going to go there quite yet, though, since GPS on smartphones is notoriously difficult to get right and even more notoriously dependent on localized circumstances like location, installed software, the day, the weather, building interference, and heck, we don't know, the phases of the moon.

The Treo Pro, for example, shares the same Qualcomm MSM7201a chipset with the Touch Diamond and the Touch Pro and we have even floated the idea that it was not only manufactured but designed by HTC. In our own Windows Mobile Forums we are now seeing reports of unduly long acquisition times and GPS drops that vary by software. The Treo Pro does seem to have differing performance depending on which app you use it with, as this roundabout solution to getting it to work faster in Windows Live Search details. We haven't run across any Treo Pro users reporting GPS lag, however.

If nothing else, it's becoming clear that something is going on here. The number of reports from users who clearly know their stuff when it comes to smartphones appears to have risen above the level of sporadic GPS problems. In fact, users in the XDA threads have reported that their GPS lag problems vanish when they use an external bluetooth GPS receiver.

What we need now are more datapoints. Have you ever experienced GPS lag? We are talking the kind where your position is well behind where if should be, not simply long acquisition times. If you've had GPS lag, what smartphone and what software are you using?