November 2009 Archives

I have recently been testing out a compact GPS receiver from the people at www.mobileaction.com. This Taiwanese company produces a range of small GPS devices suitable for walkers, cyclists, and other travellers. The unit I have been looking at is the GT-200e 'Bluetooth GPS Travel and Sports Logger'. It claims to be 'Easy to use, Supports Google Earth 3D effect, Stylish Design, and Water Resistant for outdoor activity'. It is supplied in a sturdy plastic case, and comes with a USB connecting lead, arm-strap, and CD containing the drivers, manual, and required software.

Contents of the GT200e package

The unit is quite compact at just 46x41.5x14mm, and weighs 37 grams. It has a single on/off button, and 2 LED indicators, one red and one blue. These are used to indicate the various operational states and status, such as data logging, transfer, charging, and BlueTooth pairing. The GT-200e uses the SiRF StarIII low-power chipset, and has its own built-in GPS patch antenna. Connection is via USB1.1 or Bluetooth V2.0.

The GT-200e connects to a computer using the supplied USB lead. This has a unique connector of their own design, which I consider a bad idea. Speaking as a traveller, the last thing I want is to carry yet another unique lead that can't be used for anything else. I thought that every company these days, apart from Apple, had standardised on the 'mini-USB' connector, yet Mobile Action have decided to design their own. I questioned them about this, and was told by their helpful spokesperson that they were concerned about keeping the unit water-resistant. This doesn't seem to bother Garmin, though, who use the 'mini-USB' connector on their fully waterproof receivers. I use the same cable for my Garmin, my camera, my card reader, and my external hard-drives.

GPS Logger Wear and Attachment

To install the GT-200e on your computer, it is necessary to load the drivers and the operating program from the supplied CD. The software is suitable for PCs running Windows 200,XP, or Vista: Apple Macs are not supported. I found that the installation went OK, though the next time I plugged in, I had to reinstall the drivers a second time. After that, everything was OK. The CD installs the main operating program '@trip PC', a trip-viewer program, and a Help guide. I noticed that Help guides for all available languages are installed, wasting disc space. I would prefer to be able to choose just one language, and suspect that most other people are the same!

The Help guide is quite comprehensive and easy to follow, and the English translation is adequate. It guides you through the full operating procedure, which with only 1 button and 2 leds is quite straightforward. The leds tell you when the power is turned on, when it is charging, and when it is receiving GPS data.

When first received, the unit needs to be charger through the GPS connection, which takes about 4 hours for its initial charge, and 2 hours subsequently. The internal battery is a 750mAh Li-ion rechargeable type, but is not removable, so it is not possible to carry a spare if you expect to be away from your computer for a while. However, the claimed battery life is 30 hours or more, so this may not be a problem for you.

Setting the Tracking Interval

Initial hardware settings are accomplished via the '@trip PC' program. I chose the 'Running' profile, which records a Waypoint every 5 seconds. If you change to the 'Walking' profile this will record a Waypoint every 15 seconds, but also increase the battery life to 80 hours. Other faster profiles, such as 'Cycling' or 'Driving' also activate the optional 'Smart Tracking Mode', which can reduce the Waypoint interval automatically when your velocity increases via a pre-determined amount.

To start the unit, press the button for 1.5 seconds. The GT-200e will then look for and lock on to the satellites. Once the first GPS fix is successfully acquired, both the blue and red LED indicators of GPS Logger will blink simultaneously twice. I found that this took about 65 seconds to achieve. Track logging starts immediately, based on the tracking interval configured in 'hardware settings'. There is currently no way to tell just which satellites you are receiving, how many satellites you are receiving, or what the current signal strengths are, even if the GT-200e is plugged into a PC, though the spokesperson at Mobile Action says this will change in the next software release. After using the Garmin 'GPSmap 60Cx' for so long, I have got used to its comprehensive display and ability to monitor the satellites being received at any time, but if you are a new user of GPS receivers, the twin flashing leds on the GT-200e may be enough.

To check the GT-200e, I powered it on and took it for a walk to see how it would perform. I also took along my Garmin 'GPSmap 60Cx' as a comparison. It is, of course, rather unfair to compare a fully featured GPS receiver like the Garmin with a small one-button model at a fraction of the price and specifications, but that's the only comparison I have with me, so it will have to do.

Overview of route recorded by the GPSmap 60Cx

Overview of route recorded by the GT-200e

My walk took a total of 45 minutes, 44 seconds, and covered a distance of 2.7Km at an average speed of 4 Km/hour. Approximately half of the walk was along the beach, and the remainder changed altitude as I climbed an inland hill to do a little shopping, then headed back through the coconut groves, which seemed to make little difference on the received signal of either GPS receiver.

Detail of route recorded by the GPSmap 60Cx

Detail of route recorded by the GT-200e

Back at my hotel, I downloaded the day's .gpx file from the Garmin using 'Windows Explorer', which lets me access the stored files directly. When the GT-200e is plugged in, nothing appears on 'Windows Explorer' or 'My Computer', so to access the recorded data you must launch the '@trip PC' program, which does the importing for you.

The importing goes quite smoothly, and the tracks are stored on the computer. Looking at the properties of the track, I was told that the 'Original Points' for the track were 556, and the 'Resultant Points' were 363, which worried me slightly, as I don't like programs that massage the raw data before I have a chance to look at it myself. The next surprise was that unless you have an internet connection to your computer, you can't display the track on your screen, or examine it in any way. I don't have an internet connection on my laptop, which has the drivers and control program on it, so the only option is to export the data as a .gpx or .csv file for examination in another program, such as Garmin's 'MapSource'. I compared the files from both GPS receivers, and the results are shown below. The GT-200e gives a VERY good account of itself. It is obviously recording more points than the GPSmap 60Cx, and both maps are fairly similar, as you would hope!

The altitude profiles are rather different, though, and the GT-200e shows some rather strange results. I guess that this is due to the number of satellites being received, which will decide the accuracy of a 3-dimensional fix. The GPSmap 60Cx receives up to 12 satellites simultaneously, and can get a positional accuracy of up to 4 metres. The GT-200e doesn't state how many satellites it receives simultaneously, so I can't comment.

This image shows the vertical profiles of both routes. The profile for the GPSmap 60Cx is on the top, and the profile for the GT-200e is on the bottom.

Vertical profiles of both routes

I wasn't able to check out the online map creation and trip-sharing at this time, as I don't have an internet connection on the laptop I use in my hotel, but will check this out at a future date, and report back then. I mentioned to Mobile Action that it would be useful to plug the GT-200e into a computer whilst it is receiving satellite fixes, and view the signal strength and other satellite data - this feature may be implemented in a subsequent software release.

Final thoughts...
This unit is a low-cost entry into GPS mapping, and a good introduction to the techniques involved. It is suitable for someone who needs to map their walks and geo-reference their photos to share with friends - it shouldn't be regarded as a serious, high accuracy device for life-critical applications. To get the most from the GT-200e you will need access to a PC whenever you wish to charge the unit, save the data, clear the data to start a new session, or change the profile from, for instance, 'Walking' to 'Driving'. As the software is not 'portable', (it can't be run from a USB flash drive), this means that the traveller needs to carry his own laptop around with him. It is not suitable to use from an internet cafe, as many do not allow customers to install software and drivers. To view your track, you will also need access to the internet, or other software that can view and edit .gpx files, such as Garmin's 'Mapsource' program. The GT-200e is not suitable for someone who spends much time in the wilderness, away from a laptop with an internet connection.