When GPS goes Bad

“I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to move.”
-Robert Louis Stevenson

I love GPS; my wife does not. She does not trust it and would rather use a paper map. And she's right. GPS is a great tool but never trust it 100%.

When we drove from NY to Winnipeg, Canada, last summer, the GPS led us to a bridge that no longer exists. We could see that there was once a bridge but it had been torn down and replaced by a new bridge perhaps a mile away. This was a case where we had to trust our eyes and overrule the GPS.

A similar event occurred to a man in Spain but with tragic result. Man Drowns After GPS Guides Him Into a Lake. "The driver was following the GPS directions when the car fell into the water, sinking in just a few minutes. Apparently, it was a very dark night in a bad rural road. The man was a foreigner who didn't know the area. When he saw the end of the road, it was too late. He didn't have time to stop the car."

The day before in Switzerland, a van became stuck on a "glorified goat trail" while following GPS instructions (pictured above). The van was air-lifted out.

A friend of ours said no one would believe that her GPS sent her on to dirt roads during a trip. We replied that we understood perfectly. The same happened to us last summer as we experience many dirt roads in the farm country of Wisconsin.  Many new GPS have a travel setting to exclude dirt roads from trip routes.

Another thing to keep in mind is that GPS positioning is not 100% accurate. We often find our GPS is about 100 yds off in predicting when to turn. Once I was on an access road adjacent to and parallelling a highway and the GPS thought I was on the highway and was not helping us in finding an on-ramp.
Bottom Line

Trust your eyes, not the GPS.

If you speed on strange roads at night or in fog you might not be able to brake or stop if the road suddenly curves or ends. I recall two such incidents. Once in the fog I was cruising down an empty road I'd never driven before when suddenly there was a barrier and the road ended without warning. (maybe I missed the warning?) Another time I drove nearly the entire North-South length of Idaho on a mountain highway. I thought the speed signs on curves were mostly for trucks and that I could safely do 10 mph higher than the suggested speed in my car. And I could, usually, except once. There was one very sharp curve that got my adrenaline pumping as I had to fight for control to keep my car within my lane and not drifting in to oncoming traffic. Lesson learned - don't speed on unfamiliar roads.

The Magic of GPS

Though the mountains divide,
And the oceans are wide,
It's a small world after all.
-Lyrics to It's a Small World

As I’ve commented before, my wife and I are not anti-technology, we’re just cheap. So we are late adopters of technology – waiting for the prices to come done to affordable levels. But once purchased and used for awhile, it’s hard to look back and imagine how we ever lived without it. A friend recently told us about being stuck outside her locked office without a ride home “in pre-cell phone days”. And who can imagine driving without a GPS? It’s like a magic map!

Do you know the history and workings of GPS? Well here are some interesting GPS factoids courtesy of pingdom.com

• There are always at least 24 active GPS satellites circling Earth, although today there are more than 30, including a couple of spares. Their orbits are spread out so that no matter where on Earth you are, you will have at least six of them in your line of sight.

• Each GPS satellite goes around the world once every 12 hours. The satellites travel 12,500 miles (20,000 km) above us at roughly 7,000 miles per hour (11,000 km per hour). They have small boosters so they can adjust their path when needed.

• The first full constellation of 24 satellites was completed in 1994. The first of those 24 satellites was sent up in 1989.

• To get a reliable position reading, your GPS receiver will have to combine the signals from at least four satellites, although in some special cases, three are enough.

• GPS was made public due to a tragedy. In 1983, Korean Air Lines Flight 007 entered Soviet airspace after a navigation error and was shot down, killing all 269 passengers. This incident resulted in President Ronald Reagan ordering the Unites States military to make the Global Positioning System available for civilian use once it was completed, so that similar incidents could be avoided in the future.

• NAVSTAR is the US military name for the Global Positioning System.

• GPS isn’t just for navigation. It can also be used to get a very exact time stamp. Every GPS satellite has multiple atomic clocks and the time is included in the signal it sends out. With the help of these signals, a GPS receiver can determine the current time within 100 billionths of a second. These signals are for example used to synchronize base stations in cell phone networks.

• Relativistic effects. The clocks on the satellite are subject to the effects of Einstein’s theory of relativity, running slightly slower than those on Earth. This is corrected by control signals from Earth Ground antennas spread around the world.

• The 50th Space Wing of the United States Air Force operates the GPS satellites.

• Until 2000, civilian GPS use was crippled by a feature called Selective Availability. It introduced a random error of up to 328 feet (100 meters) in the civilian signal to make GPS less useful for precision navigation. (GPS has different signals for military and civilian use.) Selective Availability was deactivated in May 1, 2000. The United States still has the ability to deactivate the civilian signal, if need be even for specific regions.

• NAVSTAR GPS isn’t the only game in town. There are several other Global Navigation Satellite Systems in existence or on their way: The European Union is working on a system called Galileo, Russia has GLONASS (completed in partnership with India), and China has plans for a system called Compass. There are also systems that offer specific regional coverage, for example Japan’s QZSS and China’s Beidou.

Bottom Line

"Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke

GPS Saves the Day!

“There’s no need to fear, Underdog is here!”
– TV cartoon show

My wife & I are late technology adopters. We are not luddites (i.e. anti-technology) but we are often the last amongst our friends to buy a cell phone, use the internet, buy Cable services, buy a large flat screen TV, etc. The chief reason is cost. We wait until technology becomes cheap.

This year we finally purchased a GPS. And after a two-week road trip to Winnipeg, Canada and back we are so glad we have it. At one point in North Dakota we had 40 miles of driving range left before we ran out of gas. The GPS told us where to find the nearest gas station. During the trip we visited lots of oddball attractions recommended by RoadsideAmerica.com. The GPS helped us find them. If a major road had delays, the GPS plotted a detour. And while our route was predetermined, we were never sure just how far we would travel on any given day. The GPS helped us find motels each night.

If you are an active hiker or camper, consider buying a portable GPS. The article, 10 Ways That Your GPS Can Save Your Life, has several stories of someone lost or stranded but able to call rescuers and give an exact location using their GPS.

Some clever uses of GPS from the article include:

• A GPS tracking device (shot at the fleeing vehicle) for police car chases
• A GPS tracker in the shoes of Alzheimer patients
• Cargo smart airdrops using GPS
• GPS tracking bracelet for children

The story, Car Horns Warn Against Natural Disasters, describes the eCall emergency system, which will be required in new European cars after September 2010. The eCall system consists of a GPS sensor and a mobile phone component, which is automatically activated in case of an accident (i.e. when the airbags are triggered) and transmits data (e.g. accident time and coordinates) to an emergency call center.

Bottom Line

A basic model GPS will cost from $70 to $200. You can spend more if you want Blue Tooth, traffic reports, music uploads, games, etc. We got lucky and purchased a discontinued deluxe model at 70% off. One advantage of the deluxe model was multi-point trip planning. During our road trip I was able to enter in all the stops we wanted to make that day and find the best route.

Do keep in mind that GPS is not perfect. While it may know road speeds (usually), ours was clueless about stop signs and traffic lights. It might divert us from a main road to a residential road where the speed limit was similar but we had to stop every block for stop signs. In Amish country it sent us along many dirt roads. And sometimes an error in the address like W vs. E or Lane vs. Drive could send us on a wild goose chase. And the data may be out of date. When we were low on gas in North Dakota, the first station it sent us to had gone out of business.