This is a note to share my first impressions of the new Microsoft
u-Blox 5 USB GPS Stick in contrast to some other GPS receivers I have.
First, the test conditions. I live in a small city of 200,000 on the Canadian Prairies. We don't have deep canyons of tall concrete and steel buildings, narrow mountain canyons or dense forests of tall trees. That's a complicated way of saying that we have pretty much perfect GPS reception conditions no matter where we drive. So reception in bad conditions isn't an issue for us. And, as a result, it's rather difficult to test. Not that I'm complaining.
So I decided to try to simulate difficult conditions by driving my laptop in my living room. There are spots where I can get decent reception and some where the reception is pretty awful.
For some additional background on the testing, although these receivers both come with Microsoft
Streets&Trips, S&T is not one of my favorite programs. For this sort of testing it doesn't provide any help at all. So most of my reception testing was with
Garmin's Mobile PC, Garmin's nroute and iNav's
iGuidance. All of these programs provide lots of useful information about how many satellites are being received, the signal strength and the estimated accuracy of the location lock.
The u-Blox 5, which comes with Streets&Trips 2009 sold in Canada, is similar in many ways to the Pharos 500 that still comes with Streets&Trips 2009 sold in the US. It plugs into the USB port and it comes with a USB extension cable so you have a little bit of flexibility where you place it.
I found that the connector on my Pharos 500 is a little flakey so it doesn't matter whether it's plugged directly into a USB port or into its extendor cable, I have to wiggle it to get a good connection and it doesn't take much to make it lose contact. That's probably only a problem with my particular unit. By contrast, the u-Blox 5 has a solid snug fit every time, in either a USB port or its extender cable.
Both units are about equal in performance. There is too little difference in the signal strength and reported accuracy in either of them to pick any "winner" in performance.
Both have the same limitation. They need to be plugged into a USB port, either directly or with their extension cables. Having them plugged into the USB port absolutely limits their location to the side or back of you laptop PC. This is almost always a bad place for reception. Over the next few days I'll be doing some driving with them to see if the limited reception is enough to impact typical in-vehicle navigation use.
Using the extension cables give you a little flexibility to place the receiver in a more desirable location. Here there is a difference between the two. The cable on the Pharos 500 is longer, thinner and more flexible. The cable on the u-Blox 5 is a bit more of a problem to use because of its shortness and stiffness.
One other difference between the two receivers is their lighting. The Pharos 500 lights up with a soft blue light when it is powered up from the USB port. There is no other indication of how, or whether, it is functioning. The u-Blox 5 has the word "Microsoft" on the top and it is backlit. It is on solid when it is powered from the USB port and it starts to flash as soon as it has a satellite lock. I found this very useful and took some of the guesswork out of troubleshooting. But the light will be quite distracting at night. If I use it in the vehicle at night I will use some black electrical tape to cover all but the last letter or two, so I can still see how it's functioning but not be distracted by its brightness.
It has been suggested that its function is backwards; that it should blink when it's powered but doesn't have a lock and then be on steady when it has a location lock. I can't say one way or the other, but what I can say is that it's present method of operating is consistent with the standard way that
Bluetooth GPS receivers work. Their GPS indicators are on steady until they get a location lock and then they start to blink.
Both units have slippery bottoms so they don't like to stay put when you use the cables to put them somewhere like your dash. This is particularly a problem with the stiff cable on the u-Blox 5. The cable on the Pharos 500 has a little suction cup on it so you can stick it to any smooth surface, like a window, if it will reach. The only thing you can count on with the u-Blox 5 on its cable is that it's almost never going to reach far enough and it's not going to stay put.
Now to contrast these two with my three other GPS receivers. I also have two Bluetooth receivers, an i.Trek M7 and a Garmin GPS10x, and a Garmin eTrex Legend HCx handheld navigation device that can also be used as a receiver on the laptop by connecting it to a USB port.
Both of the Bluetooth receivers have a little better reception than the two USB receivers, even when placed in identical locations. The i.Trek M7 is slightly better in performance than the GPS10x. It generally gets a fix a little quicker and gets a slightly stronger signal. However, there isn't enough practical difference between any of the four receivers to be the final deciding factor in a purchase decision. All are using up-to-date GPS receiver technology. That means they are quick to get a lock and will maintain it in moderately adverse conditions.
The reported accuracy is typically 4m to 10m, depending on the reception conditions; about what you would expect from a good quality consumer GPS receiver.
Both Bluetooth receivers have the distinct advantage that they do not need to be directly connected to your laptop. Because they use Bluetooth wireless radio to communicate, you can place them anywhere within about 10m - ~30ft - of the laptop. In the vehicle, that means you can easily place them up on the dash where they can get a good view of the sky and place your laptop anywhere that's convenient.
One limitation is that if your laptop doesn't have a Bluetooth radio built in, you have to buy a Bluetooth USB dongle for the laptop.
The GPS10x comes with a really handy belt clip. I used it on the golf course this week, with the Intelligolf program on my Palm TX, and I was surprised at how well it worked when clipped to my belt. It did make a difference in reception when my body was in the way of the best satellite view, but it was never enough to stop it from being useful for giving me yardages for my golf shots.
Both the i.Trek M7 and the GPS10x have non-slip material on the bottom so they are more inclined to stay put. Both have rechargeable lithium-ion batteries that are user-replacable. That means you can carry a fully charged spare if you choose. For charging, both can be connected to a standard USB cable, like the one you use for your digital camera. So you can connect them to your laptop for charging. Both come with a 12VDC adapter for charging them in a vehicle.
Finally, there is my eTrex Legend HCx handheld personal navigation device. It can be connected with a standard USB cable and will output the same standard NMEA data stream to the laptop as the others. This little sweetheart is great as a standalone unit and has all the normal sorts of navigation functions, if you load detailed road maps into it. It fits nicely in the hand and in the pocket. But if all you want is a receiver for your laptop, it's much bigger, and far more expensive, than the other receivers mentioned.
The upside is that, if you need or want a handheld personal navigation device that you can also use occasionally as a GPS receiver for your laptop, this is a great solution. It's performance as a receiver is better than any of the other four. It's quicker to get a lock and will hold one under much more difficult conditions.
To simulate really difficult reception conditions I tried all of the receivers in my basement office. It sits right underneath the cold air return (sheet metal). I think this is a fair simulation for dense forests or deep concrete canyons. Of the five receivers, this is the only one that will consistently get a good enough signal to allow a satellite lock. The other four will occasionally get a lock, but when they do, it takes them a minimum of 10 to 15 minutes. The eTrex typically takes less than two minutes to get a lock that's good enough for vehicle navigation.
As I mentioned, I have not tried side-by-side comparisons while driving. I'll do that in the next few days. I have used all of these, individually, for vehicle navigation so I know they will function nicely, especially where I live. What I'm really interested in is whether the two USB receivers will function well enough when plugged directly into the USB port of the laptop, or when placed within the limits of their extension cables, to provide consistently usable navigation in whatever conditions I can find around here.
One final note for the technical geeks. The only receiver I could get to use WAAS was the Garmin GPS10x Bluetooth receiver, and that was only when using it with Garmin's Mobile PC. Mobile PC recognized the GPS10x and all of its features and gave the option to Enable WAAS/EGNOS. Once the GPS10x found a satellite with the appropriate almanac data and downloaded it, it was able to provide a full 3D Differential lock for Mobile PC.
None of the other navigation programs I tested with seemed to know anything about WAAS. I haven't been able to establish whether any of the others can do WAAS if you have software that would make use of it. For the non-technical folks in the crowd, that's not an issue for vehicle navigation. The difference in accuracy isn't enough to make any useful difference.
...ken...
