Reinventing Me: technology

This blue plaque remembering John Harrison is ...

(Disclaimer: Although I am employed by Telenav, Inc., a company specializing in GPS applications, there is nothing proprietary included in this article - it is all information readily available from sources such as Wikipedia).

Navigation has changed quite significantly over the years. For quite some time, mariners have been able to calculate their latitude - their distance north or south of the Equator - with reasonable precision; just measure the angle of the sun above the horizon when highest in the sky, adjust for the tilt of the earth and the progress of the seasons, and, with a considerable bit of geometry (quite literally) out comes the result. It takes quite some effort to compute by hand, but such an essential requirement at sea deserves that much attention.

Establishing longitude, however, is a considerably more challenging proposition. In theory, it's quite simple, provided you can accurately tell the time. The notion of time zones is familiar; with every degree of longitude one travels east or west (about sixty nautical miles at the equator), the times of sunrises and sunsets shift by four minutes. In other words, if an accurate clock was set in Greenwich and taken on board a ship, observing the sun at noon and checking the time difference gives the longitude. The problem, though, is to find an accurate timepiece, particularly one that would operate satisfactorily on a ship with wide ranges of temperature, humidity, rough seas, and so on. Measuring longitude precisely was so important to navigation that the British Parliament passed an act in 1714 establishing a prize, worth millions in modern terms, for anyone who could suitably make progress in this field. John Harrison was a man who dedicated his entire life to this problem, making succession after succession of better and better chronometers; quite a tall order for the times. The terms and conditions of the prize required an accuracy better than sixty miles for an Atlantic crossing before any money would be paid; as mentioned above, that requires the clock stays within four minutes of true over the entire trip.

Nowadays, with atomic clocks and GPS, it seems the problems of three hundred years ago are far behind us, but in fact, even GPS depends on something very similar to the longitude problem. While most people have some ideas exactly how GPS works, there may be some surprising details. Basically, GPS satellites transmit time signals. A receiver can read the time signal, compute exactly where the satellite should be at that time based on its known orbit, calculate the time the message took to arrive and hence the distance to the satellite, and, with a bit of triangulation from multiple satellites, work out exactly where on the Earth the receiver is. At least, that's the theory - but, with a little thought, you'll realize that can't possibly work.

Radio waves travel at the speed of light, three hundred million meters per second. Even if time measurements for GPS were accurate to a millionth of a second, that's three hundred meters - hardly the sort of accuracy everyone expects from their navigation devices. And the quartz crystals in our mobile devices - yes, those very same quartz crystals that were vaunted for their accuracy when they were included in digital watches - are nowhere near as accurate as that. (The important thing about quartz crystals is not their accuracy - it's that they're ridiculously cheap). If the clocks in the mobile devices drift, it would be very difficult to compute a position on Earth; in fact, the position calculated would be thousands of miles off and maybe not on the planet at all. So how can GPS achieve the results with the accuracy we're used to? Is there another John Harrison who found a way to measure the time more accurately?

Almost. Instead, the problem is solved in a slightly different way. Instead of using GPS to locate our position in three dimensions (which would in theory take three satellites), we have to also locate ourselves in a fourth dimension, time, which takes four satellites. In essence, while our devices will incorporate an error in any time observations, that time error should be pretty much the same for all of the GPS satellites that are being observed. The time error produces what is known as a dilution of precision. The more satellites that can be seen, the more precise the calculable result. Although it might seem that your GPS device or navigation program can position you precisely, it requires a considerable number of measurements from ever-moving satellites to get that precision, not to mention a fair amount of mathematics. Something worth thinking about, when you find yourself literally holding what was once a secret Department of Defense technology in the palm of your hand.

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Day 040/365 - The First Circle of Hell: Greed

Image by Great Beyond via Flickr

In the build-up to the holiday season, I was fortunate enough to be following a sneak peek preview of a most intriguing novel, Steve McAllister's The McAllister Code. I'll try to describe the book here, but that won't do it too much justice. Simply saying "It's about two wise-cracking aliens who visit Steve and convince him to write a book that will turn his hometown of Sarasota, FL into a marketing mecca" seems like it wouldn't achieve too much, but that's exactly what the book is about.

Or rather, that's what the book isn't about. There are several other recurrent themes throughout it, some striking, some novel, and some that will strike a chord with many readers. (There's my plug: go buy the book as I intend to, and tell @inkensoul I sent you). One theme Steve reiterates is something that I have believed for a long time. Businesses can be successful without being evil. For a long time it has been held that the "greed is good" images perpetuated in the Nineties were the model of how businesses should compete; win-lose, zero-sum games, triumph or die. One of Stephen Covey's seven habits is often quoted as "strive for win-win" yet only recently have companies appeared that can actually thrive on that model. It takes a huge amount of nerve to be the first adopter of that kind of policy and exchange short-term gains for long-term successes for all. It seems to be the sort of strategy that is only successful, once everyone accepts it. Although I was intrigued, I must admit, I had my doubts that such businesses could be successful. Yet, even as I read the daily excerpts from Steve's book, I ran into the following three quite remarkable examples.

Firstly, I'd like to mention Qualatek, right here in Hollister, California. My change in circumstances recently meant that C and I ended up sharing a laptop for a little while. This was quite an enlightening experience for C, as, suddenly she discovered that sharing a computer with a code monkey is quite a proposition as the poor machine begins to grunt and groan under the strain. I believe it lasted somewhere around a week before the monitor gave up the ghost. A quick peek inside seemed to confirm that it was a worn-out cable; it also confirmed what I believed about the interior of laptops. Nobody in their right mind should try to get inside one. It takes a can opener, and the number of bits and pieces is simply mind-boggling. Hence I started on my search for a repair professional, which is relatively easy, provided you don't mind being treated like dirt. Typically, computer repair folks will charge you the earth for an initial 'diagnosis', after which they'll then tell you what you might expect to pay should you decide to repair it or not. You're out of pocket immediately. Both C and I have had bad experiences this way that have left a terrible aftertaste. Enter Nick from Qualatek, who quite happily accepted my initial diagnosis, sat on an eBay auction for the missing part over the Christmas break, ordered it without even setting eyes on the machine, took the machine to fit it, and let me know that didn't cure the problem, then ordered a new display - all without any strong-arm or hard sales tactics. The whole experience has built such a level of trust that I know he is going to fix the problem, competently and economically, and I won't hesitate to recommend him to everyone. A wonderful way of doing business.

That "change in circumstances" I mentioned above was finding myself unemployed just before Christmas. Of course, everybody makes a comment that it's a terrible time to find yourself out of work, as if there was ever a good time, as if your sudden lack of a paycheck would overshadow the festivities and that would be the only thing on your mind. Of course, it's true it isn't a good time to be looking for work - but for many other reasons. So many corporate HR departments and recruiters are taking time off for the holidays that getting a response from anyone is difficult in itself. In December, I made something like sixty submissions to many and varied companies in the area, using the big-name job search sites that everyone has heard of. In the midst of all this I discovered Jobfox, and can certainly testify to its effectiveness. Like the other sites, there are benefits for premium membership, offers for resume writing services, and so on - of course, the companies have to make their money - but I was most surprised at the level of questions required during my initial sign-up for an account. As a result, the opportunities I was offered, which from the other sides were simply the same old stale postings that I'd seen throughout Christmas, were new, fresh, and more importantly, precisely targeted to my skills. The other sites had been fruitless for a month. It seemed within a week of Jobfox, I was well on my way to securing my current post. (Another mention here of course goes to my new employer, who distinguished themselves by acting surprisingly quickly over the Christmas and New Year break while other companies and recruiters let the holiday slip by).

Finally, one more mention of how human ways of doing business really make all the difference. We ate at Flames in San Jose after one of my job interviews, and were amazed at the friendly atmosphere, quality (and quantity!) of food on offer. We had a good conversation with the table server about where I had been that day, and wishing me good luck in my search. Of course, a recommendation for a restaurant always comes with a risk. You wonder whether or not your experience was a one-off; whether next time you go there it will not meet expectations, or worse, you take someone else there and things are terrible. C and I decided we were going to take two of her sisters there for their dinner after arriving in San Francisco airport last week. Fortunately, the food quality met - no, exceeded - our previous expectations, everyone enjoyed the food and the atmosphere. The biggest surprise though was most unexpected, the table server from our previous visit recognized us, asked me very directly and specifically about whether I had had any luck in the job search, and remembered so much from our previous visit. He surely had served hundreds of people in the interim, yet remembered everything, treated us well, and of course earned his tip. That's service, and that's a better way of doing business for everyone.

The coconut pie was wonderful, too.

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Reinventing Me

Wednesday, February 2, 2011

Two navigation technologies, three centuries apart

Wednesday, January 12, 2011

A Better Way Of Doing Business