I was traveling west on a dirt road in Mexico’s central highlands region. Rolling terrain with few land marks afforded little opportunity to get a fix on my location. The Garmin GPSIII was beginning to show the little village of Pinos on the map display and my WayPoint was now coming into view. Mexico’s Highway 51 was showing to be dead ahead and the mileage indicator was indicating 23 miles to the highway. On course and completely orientated, the GPS again provided that confirmation that all was well and I was on the correct road and heading toward my next Way Point!
The situation described above is just one example of how a GPS can make adventure touring more fun and help one to navigate across areas not on the standard road map. The purpose of this article is not to explain the intricacies of how a GPS works but to familiarize people to the advantages and practical uses of a GPS on dual sport type touring. The article will explain basically what a GPS is, how they work, different types of GPS receivers, and a few practical examples of use in the dual sport adventure touring environment. The article will explain some terminology such as Waypoints, Routes, Trackback, Goto, and route planning. Finally, some opinions from the author on advantages, as well as some disadvantages of using a GPS on a dual sport motorcycle. A few safety tips are in order as well as information on accessories, mounting and powering a GPS on a dual sport bike. The author has purposely written this article from the perspective of the “new user.” The author is not an “expert” on GPS usage but is simply attempting to pass on information and perspectives from a “new user” point of view.
What is the GPS (Global Positioning System)? The global positioning system originally started out as NAVSTAR, specifically for military applications throughout the world. The utility of position finding from orbiting satellites was quickly recognized by other non-military agencies in the United States, and the DOD was quick to realize that a global positioning system would be in the best interest of everyone. Twenty four satellites, plus three spares, orbit the earth twice a day at an altitude of 10,800 miles. This bird-cage constellation of orbiting satellites always assures anyone in the world that they could see at least six satellites above the horizon at any time.
These radio signals carry satellite time ticks, which are kept accurate by on-board atomic time measurements. The GPS receiver calculates the distance to each one of the satellites by the amount of time delay and the velocity of radio waves in both free space as well as through the atmosphere and ionosphere at certain elevations off the horizon. The misnomer is to call these calculations “triangulation.” Since we are not taking bearings on the satellites, but rather measuring time delay, this is technically called “trilateration.”
Once your GPS goes through these calculations on three or more satellites in view, it self-calculates three or more arcs of time delay that will come close to a specific spot of intersection. But since the clock inside your little GPS receiver does not have an atomic standard, clock error within your receiver is neutralized by adding or subtracting a certain amount of time from all satellites uniformly. It does this until a close intersection of time arcs occurs within the brain of your hand-held or dash mounted GPS. This takes about half-second of time after about a three minute warm-up.
Once the GPS has calculated a position fix, you’ll usually have anywhere from five to twelve satellites in view. The receiver will then continuously select the best satellites in view to update your position. Although a GPS receiver needs four satellites to provide a three-dimensional (3D) fix, it can maintain a two-dimensional (2D) fix with only three satellites. A three-dimensional fix means the unit knows its latitude, longitude, and altitude, while a two-dimensional fix means the unit knows only its latitude and longitude.
Accuracy – For the average GPS user, accuracy is a mute point as generally the GPS is much more accurate then our ability to navigate! There are situations when accuracy might be important; finding the exact spot to return to a favorite “fishing hole!” Precise harbor navigation in a fog situation. Returning to a favorite deer stand. Accuracy,therefore, depends on the application and the typical dual sport application would allow for some error. Would being within 100 feet of your desired Waypoint satisfy you?
The Department of Defense (DOD) guarantees GPS position accuracy 95 percent of the time to within the radius of a 300- foot circle. This error factor is a “man-made” error imposed by the DOD for security purposes. This man-made error is called “selective availability.” The DOD, for security reasons, purposely “dithers” the clock oscillator frequencies in each satellite in a seemingly random, though absolutely controlled manner.
In addition to man-made accuracy errors there are other natural satellite signal delays that are not always predictable, such as slow down of incoming signal as it passes through extra dense regions of our ionosphere. There is also receiver noise when signals may get covered up by external hash in a city as you drive down Main Street. There is also multi-path error when these ultra-high-frequency, spread-spectrum radio signals take a bounce or two off nearby buildings. And there are also errors in geometry when your GPS receiver may lock onto three or more satellites, all in one general area of the sky, creating time delay arcs that don’t intersect at 90 degrees.
About half the time, your position is generally within the radius of a 100 foot circle!
There are two basic types of GPS receivers on the market today that adapt to the motorcycle community.
The original and still popular models are those that show waypoints, routes, distance and time information, track, heading and “trackback” routes. These GPS’s do not have a base map (road map) and, therefore, do not show terrain features and items normally found on a typical road map. These GPS receivers are less expensive then “map Based” GPS models and generally will provide all the needed information to navigate in the dual sport environment. They are simple to use, effective, and have been in use for many years.
The price range for these units has dropped considerably in the last few years. A good unit can now be purchased for around $175.00 to $250.00 . Garmin and Magellan are popular models purchased by many campers, sailers, aviators, and adventure travelers.
Many of the GPS manufactures are now introducing the “map Based” GPS receivers at a reasonable cost. The model shown here is a Garmin GPSIII model. As you can see, the road map is visible at all times and one can observe their movement across the map from waypoint to waypoint on a pre-determined route. The map image will automatically zoom in or out as one approaches a waypoint and the detail will increase as the map zooms in. As you can imagine, the map base model provides greater navigation capability as one can see terrain features, roads, lakes, seashore and other major map features.
The map shown here is a small scale map showing a large section of the Atlanta, Georgia area. The user can vary the scale by zooming in or out with a simple button control on the GPS. There are many advantages to the “map based” unit. One advantage is the designating of “waypoints” by simply placing the map pointer on a location and pressing “enter.” This will automatically make this position a “waypoint.” More about “waypoints” and other terminology will follow. The Garmin GPSIII shown here sells for about $360.00 – down considerably from just a year ago!
Understanding the common terminology of GPS usage helps one understand the method of operation, which is common to all units. Waypoints, Routes, Trackback, and Goto are vocabulary common to GPS operation.
Waypoints – Waypoints are specific locations on the earth’s surface that the user designates by entering a latitude/longitude and giving that location a name or number (or symbol). One may enter hundreds of waypoints into their GPS memory. One might ask how one obtains latitudes and longitudes (Lat/Lon) to enter as waypoints? There are a number of methods to use:
1. Take the lat/lon off a map sheet. (Least accurate unless one has a large scale map)
2. Use a map program like Delorme’s “Map-n-Go” or “Street Atlas” to obtain lat/lon’s (one may place lat/lon’s on a map or screen at any point one chooses.
3. Use Microsoft’s “Virtual Globe”. The program will show lat/lon for any place you position the map pointer.
4. With the map based GPS (like Garmin’s GPSIII) one can make a waypoint simply by placing the base map pointer anywhere on the map and pressing “enter.”
Routes – Routes are specific directions from one place to another using pre-entered waypoints to define the route. Most GPS units provide an option for setting up routes using the pre-entered waypoints and then naming each route with a unique name. A route could have a few waypoints or hundreds. The advantage of making a route is that it gives one overall distances, leg distances, leg times, arrival times, and total time for the route,etc.
Trackback – The trackback feature is a very useful feature on most GPS units. It simply allows one to press the “trackback” button and receive instructions on how to return to the original start point from ones present location. On the Map Based Garmin units the map display will show a line of dots visually displaying the return route – one simply follows the dots back! This feature is very handy when riding on trails with many turns and side trails. If one were to become disorientated (lost!) one could press the “trackback” button and follow the GPS home! Trackback routes may also be “saved” and used again to follow a particular route or even uploaded to a computer and printed out on a map for others to use!
Goto – The Goto feature is handy feature that allows one to enter many waypoints but not designate a route if a route is not certain. One would simply press “Goto” and then highlight a waypoint of choice and press “enter.” Your GPS would then set itself up to direct you to that waypoint. The map based units will do the same thing and also allow one to place the map pointer on a map feature and press “Goto” to that location.
Other items of information are provided by many GPS receivers. The following is a list of “Data Windows” found on the Garmin GPSIII:
Distance to Waypoint and Destination
Time of Arrival At Waypoint and Destination
Date and Time
Your Location in Lat/Lon
Battery Voltage – Handy when connected to your bike’s battery (acts as a battery monitor!)
Time of Sun Rise and Sun Set at your Present Location
Altitude at your present location
Total Distance Traveled and Distance Remaining
Up to three “Trip Odometers”
There are many more “Data Windows”available for applications in boating and flying.
If one understands the concept of Waypoints, Routes, Trackback, and Goto one will have a good understanding of how a GPS works! They all operate on the same basic idea – some GPS units have many more features and options but basically, the above features are those needed by the majority of travelers! Now for some discussion on recommended accessories and then a few advantages and disadvantages! There are disadvantages in this writers opinion!
Accessories The following is a list of recommended accessories one should consider when purchasing a GPS receiver:
External power cords – You will need one for use in the home to connect to a suitable 12v power source (purchased at Radio Shack). I bought an external power cord terminated with a cigarette lighter adapter and then bought a 12v power source from Radio Shack that had the cigarette female adapter attached. This will save on the use of many batteries when using the unit in your home to plug in waypoints and routes. I purchased a separate cord for use in my car.
External power cord (unterminated) for use on your bike. Connect to the battery.
If you plan on using your computer to up-load and down-load map data you will need a serial port cable that connects to your particular GPS receiver. When making a decision on which GPS to buy the ability to connect to a computer might be one of your considerations.
There are a number of mounts available from both the manufacturer of your particular unit to a number of after market sources. Handlebar mounts are generally available for all units.
Many mounts are available for Garmin GPS models from the
CycoActive Products Company (800) 491-CYCO.
A German made mount for dual sport handlebars is available for the Garmin GPSIII from “Ride West, Inc.” (800) 527-7433.
CycoActive Products also sells this mount as well as specializes in the Garmin product line of GPS units, mounts, and accessories. They are very knowledgeable about GPS use in the Dual Sport environment. Call them at (800) 491-CYCO.
I would recommend purchasing the DeLorme map program “Map’N’Go” (Version 4.0). This map program includes all of the Western Hemisphere and will provide Lat/Lon data for any point you place the map arrow and “click” for Lat/Lon data. This program also interfaces directly with many GPS receivers. The Garmin GPSIII can even upload and down load routes and waypoints directly from Map’N’Go. DeLorme Company
A case designed for your unit
Advantages – The GPS is a tool that should supplement good map reading skills. The GPS will make navigation easier and more precise over terrain that is not well mapped. It can help one determine trail heads, side roads and generally make navigation more enjoyable when landmarks are not well defined. It certainly provides a degree of security if one becomes disorientated (lost) and in an emergency situation it could make the difference in finding medical help quickly if a riding buddy were to become injured. The more one uses a GPS the more one finds additional uses that make travel more enjoyable!
Disadvantages – Yes, in this author’s opinion there are disadvantages! From personal experience the author can tell you that one can become “focused” on the GPS at the risk of not focusing on the road! It takes an effort not to become involved in the GPS over the map. Map reading and navigation are skills that should come first and then the GPS used as a secondary means of navigation or confirmation! The GPS needs batteries, external power, care and handling. It can be another “thing” one must deal with at the cost of the freedom we all look for on a motorcycle. If you are a “free will” type person you may not even want to be encumbered with a GPS. If you are like the author, “anal-retentive”, a term given to me by my good friend Pete in North Georgia, then you will love the GPS! You decide if you really need one!
In conclusion, the purpose of this article has been to introduce you to the GPS and its use as a tool for dual sport riding and touring. The description of how it works was kept simple and to the point. A number of terms; waypoints, routes, trackback, and goto were explained to help you understand GPS operation. Finally, a few points on advantages and disadvantages were pointed out to help one decide if the GPS is something one must have! You will have to make the decision .
The following URL is provided for those wanting to look at many different GPS models and their cost. The Navtech Company is one that stocks many of the popular brand and model GPS units. They provide a good service and are a very useful source of information on questions one might have prior to making a purchasing decision.
Contact the CycoActive Company at (800) 491-CYCO for information on Garmin GPS products, mounts, and accessories.
Those wanting to contact this author may reach me at: [email protected]