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Domain: mehaffey.com

Stories and comments across the archive that link to mehaffey.com.

Comments · 7

  1. GPS Information by Anonymous Coward · · Score: 0 · on New GPS Standard Published

    A great site for information about GPS is Here

  2. SA is now off! by thogard · · Score: 2 · on GPS Civilian Signal Degradation Turned Off

    Wow, the Whitehouse didn't just put out a press relase...they did something too. SA is off!

    Heres a graph of the improved accuracy.

  3. GPS links by Jafa · · Score: 2 · on GPS Civilian Signal Degradation Turned Off

    (Sorry if this is a repost, this didn't post the first time)

    This is awesome news. I use gps nearly every weekend, and it's always bothered me a little knowing that it was off a little bit.

    Anyways, for more info here are a couple of links to gps sites:
    GPS Info Website is an awesome starting point. Tons of links and info.
    GPS and NMEA- A good FAQ site on gps in general and also hooking a unit up to other equipment (hand computer, autopilot, etc.).
    US Coast Guard Nav Center has some good updates and status of gps.
    Garmin- A well known gps maker, their site also has some good general info on gps (not just their units).

    Anyways, have fun out there!
    Jason

  4. gps links by Anonymous Coward · · Score: 1 · on GPS Civilian Signal Degradation Turned Off

    This is awesome news. I use gps nearly every weekend, and it's always bothered me (just a little) knowing that it wasn't as accurate as it could be.

    Here are some good links to gps info:
    US Coast Guard Nav Center Great status info and general policy stuff.
    GPS Info Website The best central source of info on gps that I've found so far. Tons of links and content.
    GPS and NMEA Site Another good source of info, including hooking up a gps to other equipment (hand computers, autopilots, etc).
    Garmin A well know maker of gps units, their site also has some decent info in general on gps.

    Anyways, have fun out there.
    Jason

  5. Re: GPS for aviation by Ledge+Kindred · · Score: 3 · on Space Shuttle Displays Go Glass
    If you have a military GPS receiver, you can decode the encrypted military GPS signals that are on a different frequency than the civilian signals which will allow you to find your GPS coordinates down to a few inches.

    But there are a lot of other reasons why GPS isn't very good for aviation use:

    GPS does not handle altitude very accurately.

    GPS does not handle very high speeds all that well.

    I imagine the GPS system would break down entirely when you reach a good percentage of the altitude of the GPS satellites themselves. Not so good for the shuttle. (Seeing as this is what the article is about...)

    Here's a great URL for lots of info on how GPS works: http://www.trimble.com/gps/index.htm (It uses Shockwave, but you can still view it without.) Here's another with lots of information about GPS units: http://joe.mehaffey.com/

    -=-=-=-=-

  6. good information by M-G · · Score: 1 · on GPS Rollover Tonight
    Being a former employee of a major GPS manufacturer (I won't say which one...just that I got laid off because they were seriously in debt), I can tell you that the GPS design community is well aware of the week rollover problem. The problem isn't inherent in the GPS system itself, but rather in the specific units. The ground segment has the responsibility for handling local time....it doesn't really matter to the computation of satellite position. Some early units simply don't account for the rollover, so it's going to take them a while to figure out where they are.

    Two good links about this:

    http://joe.mehaffey.com/y2000dat.htm
    http://joe.mehaffey.com/y2k-sv.txt

  7. good information by M-G · · Score: 1 · on GPS Rollover Tonight
    Being a former employee of a major GPS manufacturer (I won't say which one...just that I got laid off because they were seriously in debt), I can tell you that the GPS design community is well aware of the week rollover problem. The problem isn't inherent in the GPS system itself, but rather in the specific units. The ground segment has the responsibility for handling local time....it doesn't really matter to the computation of satellite position. Some early units simply don't account for the rollover, so it's going to take them a while to figure out where they are.

    Two good links about this:

    http://joe.mehaffey.com/y2000dat.htm
    http://joe.mehaffey.com/y2k-sv.txt