Friday, May 16, 2008

Feeble GPS:

If you're driving through a long tunnel, and your car sports a modern GPS, why, then that GPS will be happy to draw a picture for you, to show you that you're under a great body of water. I've just completed my first serious immersion in GPS-life, driving 700 miles in a rental car over roads familiar and unknown. I have an awful lot of impressions to sort out, such as the fact that I hate to be told to "drive straight in 1.8 miles" while trying to hear an audio book.

But here's what you should bear in mind about today's driver-GPS systems: They are feeble inventions of great ingenuity. In the future, we'll look back at them, and we'll laugh.

A GPS ought to be tightly- coupled with its automobile. Many quirks of its user interface derive from the GPS computer having so little idea of, or knowledge of, what's going on. The next time your'e bored, imagine what a GPS would be like if it had these capabilites:
  • It would know your location to within an accuracy of one foot; it would know if you were in the correct lane.
  • It would monitor the turn signals; it would know if you intended to make a turn as instructed.
  • It would be able to operate the turn signals for you, if you preferred not to signal manually.
  • It could advise you when to brake, or that you're going too fast, given the curviness of the road.
  • It would know whether you had enough gas to reach your destination, so it would know when to direct you to a price-competitive gas station.
  • My GPS asked me whether I wanted the shortest route, the route with the most super highways, or the route with the least super highways. Over time, this list of alternatives will expand to include choices of familiar/unfamilar routes, fuel-efficient routes, and (I think some high end systems have these): routes to avoid bad weather, construction, or traffic jams.
  • A GPS that knows the weather and the traffic can tell me when it's advisable to turn cruise control on and off.

I believe there are already GPS systems that handle audio input. This business of pressing buttons to slo- ... -wly program an address is ridiculous. My GPS warned me not to program it while driving. It then required me to press several buttons (while driving) to confirm I was resuming the last driving plan. GPS systems that take weather and construction schedules into account can do something else that's rather clever: they can suggest what time of day I should start driving, for best time and weather. And so on, and so on, and so on.

Today's GPS developers have been ingenious, doing so much with so little. But what we're enjoying is only a primitive new technology.


Ender said...

There's a lot of cool products now working in the space between precision mapping, location-specific information, and directions. I wonder what the final 'standard' will be, but I suspect it's going to be pretty cool - and infinitely more sophisticated than what we currently hobble along with. I just read about an interesting side take on things:

That being said, I have to admit that I see no reason to buy a GPS or any similar device at the moment. Proper planning and a map seem to be a much simpler and cheaper alternative for now (obviously with the exception of those who travel to unfamiliar places on an extremely frequent basis). Perhaps the new 'perks' of a future system might be worthwhile (i.e. asking the GPS to find you the closest open Thai restaurant and direct you to it), but for now it seems largely overhyped. After all, if I get irretrievably lost, there's always my laptop (if there's wireless) or my cell phone.


(BTW, I have been reading your book, albeit slowly. Interesting so far...) said...

I do see a reason to have a GPS. The device handled matters very calmly when I got onto a road going the opposite direction. I knew I had to make a U-turn; the GPS knew WHERE to tell me to make my U-turn.

The GPS is also good for keeping me on a route that has many false and appealing wrong turns. I would feel safe taking a "scenic" route, knowing that the GPS could always help me find my destination.

But I HATE the "estimated time" it gave for my trips, which assumed I would average 65 mph, and strongly tempted me to do just that.
- PB

Anonymous said...

As a pilot, I've been wondering how automobile GPSes work. Aviation GPSes can be augmented with a system called WAAS, and WAAS-enabled GPS units are accurate to within 10 meters (if I recall correctly). Without WAAS augmentation, it's much worse. So how can an automobile GPS be accurate enough? Two possibilities occur to me:

1. The aviation accuracy is guaranteed accuracy. Thus the actual accuracy might well be significantly better.

2. Perhaps the software in automobile GPSes compares its location with its map and to put you on a road, e.g., if the GPS position is 50 feet east of a north-south road, and you're traveling north, it will simply decide you're on that road.

(I've never used an automotive GPS so have no experience here.)

Any idea which is the case?

At present, 1 foot accuracy is far outside the range of existing technology (unless there's something the Pentagon is not telling us). said...

I agree, 1 foot accuracy is impossible NOW. But in the future?

I thought that my GPS system assumed that the readings were inaccurate. If I did not take an indicated turn, the screen showed me making that turn anyway for a few seconds.
- PB

Ender said...

Heh, talking about accuracy of GPS, here's a fun problem: Figure out how much the speed of light would have to change before we noticed.

My friends and I guessed that one of the first things to noticeably shift would be GPS data, which depends on very, very accurate time measurement (and whose signal speed is directly related to the speed of light).

It's surprising how quickly we'd pick it up.

Conversely, is there a physical limit to the kind of resolution we can achieve (without adding more signals/satellites)? I'm fairly certainly that better resolution can be achieved, but I wonder whether the cost is worth it; the original use of GPS (i.e. military positioning) doesn't really need much more accuracy; even small J-DAMs destroy an area far greater than the resolution limit. said...

You're wrong about the military. They want soldiers who have to fight in close quarters to have a semi-transparent map displayed in front of their eyes showing where doorways are, closets, and sudden side paths. They might combine cameras with GPS to enable very tight positioning logic. Civilians can use the same, if it is ever practical.
- PB

Anonymous said...

Dear precission blogger,
I was not aware about GPS your article was an eye opener for me, Your technical orientation baffels me. I am sure there is more out there to be tabbed and hidden in your brain please keep posted technical stuffs feels I am talking to my kind. by said...

Anonymous, thanks for your comment. I'm a software developer, and I always like to imagine how a dose of software can improve existing things. For example, I want my radio to observe what I listen to, and advise me when similar material is about to play on another station. And I want my refrigerator to warn me when some food is about to spoil. I also want my fridge to give me a printout of what's inside it, and I want it to rotate food to the front when I'm likely to want to fond it.
Just use your imagination. Compuaters can eventually do what you want them to do, between the spam and virus attacks.
- PB