Mobility Site - View Single Post - NEED GPS utility to measure ALL satellite signal strength below 26db

JakeRich · 01-14-04, 08:39 AM

The Xtrack in the XT mode lagged almost all of the time, it was rarely within 5 seconds of my location, even with full satellite strength. The lag varied, averaging about 7-8 seconds, sometimes as much as 10 seconds. The Digital Signal Processing it uses to allow it to use weaker signals is very, very math intensive, using recursive calls of complex formulae to continue processing until it has milked out of the noise every part of the signal it can. I am sure that someone will make a faster processor for it, if the demand is there, but it will be very expensive in comparison to "normal" receivers. I'm actually surprised they can do it at all!

If you are walking in NYC, it's might work for you in the canyons of Lower Manhattan. In a car, it's not as useful in the XT mode, IMHO, although it is certainly better than nothing. I did review it a little while ago and that review is in the review section here on Aximsite. It's a great idea for walkers in urban canyons, hikers, mountain bikers, cross country skiers and maybe off-roaders not totally bent on high speed, but for so-called normal driving the lag is really noticeable. In the ST (standard) mode, the lag disappears, but so does the DSP processing and it becomes a competitive CF GPS that is as good as any on the market. As I indicated in the review, a good use would be to leave it in ST as you drive to the parking area, then switch to XT and as you prepare to leave on the hike/trek/bike/whatever it can reaquire the fix (cold start, remember) and you are off! When you get back to the car you swap back to ST and while you are packing up to leave it requires again and you are in business. Using that methodology, it is very attractive to those folks who do that sort of thing.

Maybe someday the swap from ST to XT can be automated based on the signal strength and some sort of indicator used to let you know what mode it is in. If that happens, then most of the time it will have little or no lag and then it will lag when it goes into XT mode. However, in the present incantation the XT delays are there whenever it's in XT mode.

Any other users of the Xtrack want to share their experiences?

01-14-04, 08:39 AM	#4 (permalink)
JakeRich Aximsite Hall of Fame Join Date: Nov 2003 Posts: 7,875 Thanked 1 Time in 1 Post	The Xtrack in the XT mode lagged almost all of the time, it was rarely within 5 seconds of my location, even with full satellite strength. The lag varied, averaging about 7-8 seconds, sometimes as much as 10 seconds. The Digital Signal Processing it uses to allow it to use weaker signals is very, very math intensive, using recursive calls of complex formulae to continue processing until it has milked out of the noise every part of the signal it can. I am sure that someone will make a faster processor for it, if the demand is there, but it will be very expensive in comparison to "normal" receivers. I'm actually surprised they can do it at all! If you are walking in NYC, it's might work for you in the canyons of Lower Manhattan. In a car, it's not as useful in the XT mode, IMHO, although it is certainly better than nothing. I did review it a little while ago and that review is in the review section here on Aximsite. It's a great idea for walkers in urban canyons, hikers, mountain bikers, cross country skiers and maybe off-roaders not totally bent on high speed, but for so-called normal driving the lag is really noticeable. In the ST (standard) mode, the lag disappears, but so does the DSP processing and it becomes a competitive CF GPS that is as good as any on the market. As I indicated in the review, a good use would be to leave it in ST as you drive to the parking area, then switch to XT and as you prepare to leave on the hike/trek/bike/whatever it can reaquire the fix (cold start, remember) and you are off! When you get back to the car you swap back to ST and while you are packing up to leave it requires again and you are in business. Using that methodology, it is very attractive to those folks who do that sort of thing. Maybe someday the swap from ST to XT can be automated based on the signal strength and some sort of indicator used to let you know what mode it is in. If that happens, then most of the time it will have little or no lag and then it will lag when it goes into XT mode. However, in the present incantation the XT delays are there whenever it's in XT mode. Any other users of the Xtrack want to share their experiences?