Research, research, research.
Problem: So these handhelds and auto units are pretty cool. They have all these maps and tracking and often give you directions. They’re a little higher priced. My biggest problem is the map updates. You have to pay for them! Google Earth is free and updates are free! Logically, I am OLD and live out in the country where roads don’t change much so what does it matter. It just gets my goat! Actually, at my house, Google Earth is using a 2003 map and doesn’t show three houses that have been built since. No matter.
USB interface to laptop
NMEA 0183 output: National Marine Electronics Association (NMEA) 0183 is a standard serial communications protocol supported by most computer GPS software.
My selection was the USGlobalSat BU-353. See picture. At the time, the best price I could find was actually Amazon.com (~$34).
Here’s the US website.
Other features I liked are the SiRF Star III chipset which is pretty highly rated, WAAS-capable and a 20 channel receiver.
TIP: 20 channels refer to the number of satellites the receiver can receive at the same time. There are only 24 active satellites at any time around the world and the most you can pick up at one time is typically 10-11, so 20 is a bit of overkill.
GPS was developed by the US Department of Defense and is maintained by the US Government.
The basic GPS receiver will give its latitude, longitude and altitude. It also runs on an extremely accurate clock. It requires four satellites to get a fix. Basically, each satellite has its own atomic clock and transmits the exact time and its position to the receiver. The radio signal takes time to get to the receiver (basically, the speed of light). The receiver calculates how long it took to get to it and therefore how far the satellite is from the receiver. With four satellites, it can pinpoint its location. With more than four satellites, accuracy is improved. Specifications for the BU-353 say accuracy is 10 meters.
WAAS: Wide Area Augmentation System is a system of US ground stations that augments GPS receivers to improve accuracy in this case to 5 meters.
Here are some good websites for more GPS information:
GPS Guide for Beginners:
How Stuff Works:
Step 1: Using BU-353 with Windows
You will need the USB driver and the GPS Info utility for your computer operating system.
I believe the correct order is load the USB driver, connect the BU-353 and load the GPS Info software.
Like most USB GPSs, the BU-353 converts USB to a software serial port.
Setup: When you run the GPS Info program, the first thing you need to do is figure out which Com port the BU-353 is using. You can click on the Scan Comm Port icon. One of them should show as GPS receiver. Then click OK and it should put in the correct Com port into the drop down box. Then press Start GPS . The data should scroll, the correct Date, Time, Latitude and Longitude should be displayed. The scrolling data is the data coming from the BU-353 or if in red, the commands sent to the BU-353. The globe and the data at the bottom display the active satellites. Direction and Speed are meaningless unless you are moving. See picture.
One nice feature is the Set Time in the upper left corner that will set your computer clock to the correct time.
WARNING: I wouldn’t send any commands to the BU-353 unless you really know what you are doing.
WARNING: It seems to me like the WAAS/EGNOS checkbox turned WAAS off instead of on. I think if you recycle power it turns WAAS back on automatically.
WARNING: The first versions of the USB driver and GPS Info I used would lock up the Com port so that I couldn’t use other software without restarting. This seems to be fixed in the latest releases.
Some other free software that supports NMEA 0183 devices:
Most software needs to know what Serial com port the GPS is using.
TIP: To find the GPS com port number in Windows XP, click on the Start icon, right-click on My Computer, choose Properties, choose Hardware tab, click on Device Manager, click on Ports (Com & LPT). One of the drop down devices should be Prolific USB-to-Serial Comm Port (COM?) The ? is the Comm port.
To find the GPS com port number in Windows Vista, click on the Start icon, right-click on Computer, choose Properties, click on Device Manager, click on Ports (Com & LPT). One of the drop down devices should be Prolific USB-to-Serial Comm Port (COM?) The ? is the Comm port.
If it isn’t there, then you may need to reboot.
WARNING: The BU-353 is a SiRF chipset, there are several utilities that are designed to work with this chipset, such as SirfGPSTweaker and SiRFTech. I was playing around with these. One of them, put the BU-353 into a state where it stopped working even after a power cycle. I was able to recover it but if you surf the web on BU-353 users, several people were not able to recover.
From what I’ve read, there are two primary modes for SiRF GPSs, one is NMEA 0183 and one is SiRF format. I suspect what happened was the BU-353 was locked into SiRF format. Unless you are more knowledgeable then I am or braver, I would stay away from SiRF utilities.
TIP: NMEA 0183 defaults to 4800 baud. Most software defaults to 4800. I would suggest you leave everything at 4800 baud.
Displays satellite information, latitude, longitude and altitude plus it does some averaging. What I noticed most is how much my altitude varies. I don’t know if this is more because of my BU-353 or my location. This software gives you a visual and mathematical example of how much your GPS data varies from sample to sample. See picture.
Setup: Click on Connect to GPS. Click on Connect using Serial Port . Select the correct Com port number.
WARNING: It seems my version of VisualGPS locks up the Com port so that I couldn’t use other software without restarting my laptop.
Displays satellite information, latitude, longitude, altitude, direction and speed. This is more like an automobile GPS. Plus it includes a US map that plots your position and route. Also suppose to be able to drop in map images and calibrate them. I haven’t tried this yet. I don’t know how this compares with auto GPS maps. The North American map is about 84mBytes. It looks like it has a lot of editing features. See picture.
Setup: Click on GPS, select NMEA 0183, select Com port number.
The toolbar attaches to Adobe Reader and uses USGS topographic maps.
Not recommended. It is totally unusable on my old Pentium III laptop. The individual maps have to be downloaded and opened with Adobe Reader. The maps are topographical, not ideal for man-made roads, streets and cities. The interface is clumsy and not very user friendly. I guess one useful application would be hiking in the mountains but then you’re not likely to be carrying a laptop.