The Awesomeness of GPS

The Awesomeness of GPS

Last weekend for Memorial Day Carolyn and I went to Baker City, Oregon, to visit my father’s grave and put some decorations on it. He died ten years ago and I had only been back to visit it once. I notified my son in Albany, Oregon, and my half brother near Yakima, Washington, who both live in easy driving distance, that I would be up there and staying overnight.

My son couldn’t make it, but my brother Gene came down and we went out and found the grave. Gene had never met his father when he was living, since his mother left our father before he was born and then put him up for adoption at three years old. So this was his first meeting with our Dad.

Since my son couldn’t be there, he asked if I could get him the location of the grave by coordinates so he could visit later using his GPS. We both go geocaching occasionally, and with the latitude and longitude we can go to within a few feet of anywhere on earth.

So after we had decorated the grave and taken some photos, I went to the car and got the GPS unit, put it down on the grave stone, tapped in the menu for coordinates, and wrote down the result. Later I posted the photos and coordinates on Facebook.

After I got home the next day, just for fun, I shut down the browser on my desktop computer and opened Google Earth, a great program for seeing satellite pictures of anywhere on earth, even under the sea. First I searched for Baker City, Oregon, and the globe on my screen rotated and zoomed in until the whole city was showing on my screen. Then I deleted the name of the city and entered the coordinates of my Dad’s grave. As soon as I clicked on it, in less than a second, a little pushpin appeared, poked right through my Dad’s  gravestone. Such a simple thing, and yet so awe inspiring to the mind of this nerd!

I’m seventy years old now, and I remember when the news of America’s first computer, Univac, was announced when I was a little boy. It could calculate the ballistic trajectory of an artillery shell in just minutes, rather than a bunch of people punching adding machines for days.

When I was twenty three, in the US Army on Okinawa. I got to program a test COBOL program on the world’s largest computer at the time, an IBM System 2- something-something or other. It processed data for all men and material in the western Pacific from Thailand, Viet Nam, the Philippines and Japan. It had five air conditioned rooms of iron core memory, four or five tape drives taller than I was, and a metal band printer that printed paper so fast it arced out of the back of the machine into a box in back. It was in the data processing center of the 2nd Logistical Command at Machinato, Okinawa.

Since I had high math scores on my battery of qualification tests when I entered the Army, I was drafted into a month of Computer Fundamentals and COBOL Language programming. I enjoyed it, but not as much as I enjoyed testing engines on a dynamometer, so when the training was done, I talked my way back to the shop. Robert Frost’s poem, “The Road not Taken” has special meaning to me. Knowing computer basics in 1966 could have led to another whole life, but I’ll never know.

I do know I’ve enjoyed the life I lived, so far! And I enjoy wondering how many of those old mainframe computers it would take to equal an iPhone.

Now that I have established my ancient nerdiness, let’s get back to the wonders of GPS. Most people don’t have a clue about the vast amount of scientific knowledge in physics, geometry, chemistry and calculus involved in that tiny little Global Positioning System. It’s not just that hand held unit, although that would be awesome enough.

To explain GPS easier, one needs to understand the history of radio navigation. First came the Non Directional Beacon, or NDB. It is just a radio sending out a roaring noise on a specific frequency, which a pilot can tune in to with a special radio receiver with a loop antenna. You can rotate the loop while listening to the signal and when the noise is loudest, you know the angle of your plane in relation to the direction to the beacon. Turn the plane until the beacon is out in front, and you’re going in the right direction. At least that’s what Amelia Earhart thought. Better than nothing, but not good enough to find a little island in the big Pacific Ocean.

Next came the Variable Omnidirectional Radiobeacon, known as VOR. These beacons sent out discrete signals that told a receiver on the airplane  the exact bearing to the VOR. You could just track to the beacon, or if going to a place without a beacon, you could tune in two or three VORs and draw lines on a chart to each, and where the lines cross is your position. It is precise enough to get you to an airport, but not necessarily in the middle of the runway.

Later some of the VORs got an enhancement called DME, or Distance Measuring Equipment. Now each signal gave you the bearing to the beacon and it told you how far it was to the beacon, so with one calculation you could find a point on the map. But it was still your calculation--the data only told you where the VOR was--you had to figure out where you were.

GPS was developed for the military in the 70’s and 80’s, and in 2000 the system was made available with full precision for civilian use. Instead of ground based beacons, the government launched 24 satellites into precise orbits around the earth. Think of the calculations involved in fuel burn, thrust, stability and vectoring to place each satellite in the exact orbit necessary. Yep, that’s rocket science!

Since the satellites are not stationary, they must be constantly calculating their exact location above the earth to the centimeter, and then streaming that data down to earth where the ground base unit can receive it. The data includes the exact time and the exact location (including elevation) many times a second. The unit in your hand or car or airplane receives signals from six or eight satellites and instantly calculates the precise distance to each satellite and then calculates it’s position in relationship to all of them. Then it can display latitude and longitude, or in the more modern ones like the one in my car the position is marked on a moving map.

The very latest ones for airplanes find your position, elevation and heading, then relate that to a detailed terrain database stored inside the unit and show a simulated view out the window on the display that precisely matches the view out the real window if you weren’t flying in rain, snow or fog. For the first time in decades the accident rate for small airplanes is dropping, probably because pilots don’t have to do mental calculations to orient themselves to earth anymore.

When I think of how far science has advanced in my lifetime, it boggles my mind that millions of people in this country would rather believe a politician or a loud mouthed radio personality who never finished college than thousands of scientists about whether the earth is warming due to human atmospheric pollution or not, and millions more choose to believe a preacher on the age of the earth than scientists who have spent their lives studying and measuring that age by a variety of methods including radioactive decay, the most precise measure of time we know.

The saddest part of all is that it is intentional ignorance! They refuse to study anything that might contradict their beliefs. They are just as sure they are right as that the sun goes around the earth.

Don Rogers
May 29, 2014