Chief Delphi - pic: Game hint

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Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Extra Discussion (http://www.chiefdelphi.com/forums/forumdisplay.php?f=68)

- - pic: Game hint (http://www.chiefdelphi.com/forums/showthread.php?t=60132)

lucasmaker#2247

22-12-2007 16:09

Re: pic: Game hint

Even taking so many theories, it can not be "Breaking the head" before the kick off, it is healthy, but many people are giving shot in the dark, as well as in other years. The only concept that we have are of new technologies, and this is good, but on the game can not know virtually nothing
...
...

...
...

Will be Triangles and not Cases, or Cubes, or Boxes, or Squares....
Will be Triangles

jerry w

22-12-2007 18:00

Re: pic: Game hint

please
it has been 24 hours.
has no one in that area got a gps unit?
google is not accurate within about 50 feet.
i would like to know what is on the ground at the suspected coordinates.

please, will someone go make the measurement?:ahh: :ahh: :ahh:

jerry w

OOPS

DonRotolo

22-12-2007 18:24

Re: pic: Game hint

Quote:

Originally Posted by Phalanx (Post 662215)

Because incandescent and halogen bulbs create light through heat, about 90% of the energy they emit is in the form of heat also called infrared radiation.

It is important to distinguish between long IR and short IR. One is what we feel as heat, the other is what IR LEDs emit. Determining which is which is an exercise left to the student.

Quote:

Originally Posted by emusteve (Post 662376)

Does this mean we can go back to sane wiring practices like using ribbon cable to wire our sensors, rather than being restricted to using big hunky 24awg or larger stuff? After all, they've been giving us 30awg PWM splitters all these years.

...or you can buy 24 AWG ribbon cable, eh? For Example

Quote:

Originally Posted by jerry w (Post 663042)

it has been 24 hours.
i would like to know what is on the ground at the suspected coordinates.
please, will someone go make the measurement?:ahh: :ahh: :ahh:

Me too.
Anyone??

Don

njamietech

22-12-2007 18:36

GPS devices are not always accurate

keep in mind that a GPS device can be off by 50 feet as well, depending on the signal quality.

DonRotolo

22-12-2007 19:03

Re: pic: Game hint

True, although since the Feds switched off selective availability it's a bit better.

Nevertheless, there are ways to get really good accuracy, for example. I have used this to locate my radio antenna tower to within a few feet.

74 01'W 41 01'N is about 32 feet NE of the tower, if anyone cares.

Don

billbo911

22-12-2007 19:16

Re: pic: Game hint

Another thought came to me today, and it wouldn't surprise me that others have thought of this as well.(If this has already been suggested/posted, please ignore mine.) :o
Could the fact that we were given GPS coordinates as a clue, mean that we will be receiving GPS coordinates, for positioning purposes, on the field? If so, the third coordinate would most likely be a height value. (Look at what is being used in Surveying and Construction these days. )

Just food for thought.

Daniel_LaFleur

22-12-2007 19:18

Re: pic: Game hint

Quote:

Originally Posted by billbo911 (Post 663062)

Civilian GPS coordinants are only good to about 10 feet and GPS signals are notorious for dropping out in some structures (like a steel building) and in high EM areas.

billbo911

22-12-2007 19:52

Re: pic: Game hint

Quote:

Originally Posted by Daniel_LaFleur (Post 663063)

Civilian GPS coordinants are only good to about 10 feet and GPS signals are notorious for dropping out in some structures (like a steel building) and in high EM areas.

For civilian GPS, you are correct. In fact, when I backpack, my GPS is sufficient. If I know where I am within 3 meters, I'm really happy!

But remember, I said to consider what is used in surveying and construction. Think in the 1cm for X,Y and 1-3cm for Z accuracy range.
Good enough for robots???

Daniel_LaFleur

22-12-2007 20:14

Re: pic: Game hint

Quote:

Originally Posted by billbo911 (Post 663069)

For civilian GPS, you are correct. In fact, when I backpack, my GPS is sufficient. If I know where I am within 3 meters, I'm really happy!

But remember, I said to consider what is used in surveying and construction. Thing in the 1 - 3cm accuracy range.
Good enough for robots???

Surveying and construction are done out doors and therefore will have cleaner signals.

To get to the 1-3cm accuracy from a non-military GPS you'd need 4-5 signals from different GPS satalites and time to syncronize them (hours). In addition, reflections cause havoc in such systems, nevermind the EM field around the robot.

billbo911

22-12-2007 20:22

Re: pic: Game hint

Quote:

Originally Posted by Daniel_LaFleur (Post 663074)

All I can say is, check this out.

DonRotolo

22-12-2007 20:24

Re: pic: Game hint

Quote:

Originally Posted by Daniel_LaFleur (Post 663074)

To get to the 1-3cm accuracy from a non-military GPS you'd need 4-5 signals from different GPS satalites and time to syncronize them (hours).

Aside from the Pseudolites mentioned above, look up Differential GPS - makes it trivial to get cm accuracy within seconds.

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