GPS fun

I love GPS. It's even better than ever, since they turned off S.A. a few years ago. Our new car has a GPS nav system built in, which is very useful. But for me, the "killer app" of GPS is not to get me where I'm going, but to tell me where I've been.

I'm a licensed amateur radio operator (ham), and I used to do a lot with APRS. I had trackers on two motor vehicles and one bicycle. But these days, I mainly track myself with a Garmin Forerunner. This unit combines a GPS with a heart-rate monitor, and provides a display typical of a regular bicycle speedometer. I can put it on any bike, and it never needs to be calibrated for wheel size. And when I get back from my ride, I can download the tracklog to my computer and see not only how far and fast I rode, but also where. Unfortunately there doesn't seem to be any cross-platform support for accessing the 301 track data, but I believe people are working on it.

I also subscribe to a web service called MotionBased where my data is aggregated, and I can (for instance) compare rides on the same route on different days. These guys are working with J2EE and SVG and other good stuff. Unfortunately, the browser support situation for SVG at the moment means they don't fully work on all platforms. The more advanced functionality which requires the SVG and the web page to work together are currently targetted at Internet Explorer on Windows. Still, they are committed to making it work with other browsers, and in a platform-independent way.

I find the 301 a useful addition to my gadget collection. I've found it to be very reliable and functional. I have only two suggestions for hardware improvements. First, the heart rate transmitter eats batteries at an alarming rate, and when the battery gets low, the heart rate data becomes very suspect. So a new transmitter chest strap that worked better would be good. Second, the device uses GPS to determine altitude. Due to the geometry of GPS, this is not very reliable. I would willingly pay $50 extra to have a barometric alititude sensor built in to the device. Garmin already sell GPSs with baro, so they know how to do it. Even taking into account these comments, I think I'd give my new toy 4.5 stars out of 5.

Comments:

I've got a Polar 625X with barometric altitude sensor, and I'm not sure that it is very reliable either. It can vary by as much as a couple of metres either way when running on completely flat ground, and if I compare its reported altitude with the altitude reported on an OS map, it can be out by 4-5m.

I think if you treat is as a general guide to total ascent/descent during exercise, then it's a useful tool. Just don't look too closely at the readings :)

Posted by Trevor Watson on June 01, 2005 at 08:07 PM PDT #

Post a Comment:
  • HTML Syntax: NOT allowed
About

terryh

Search

Archives
« April 2014
SunMonTueWedThuFriSat
  
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
   
       
Today