Anyone want to know how GPS works?
- Eriku
- Posts: 1194
- Joined: Thu Aug 05, 2010 10:19 am
- About me: Mostly harmless...
- Location: Ørsta, Norway
- Contact:
Re: Anyone want to know how GPS works?
Tbh I'm more interested in knowing what the deal with the girl with the fish is...
with.
with.
- Santa_Claus
- Your Imaginary Friend
- Posts: 1985
- Joined: Thu Jul 29, 2010 7:06 pm
- About me: Ho! Ho! Ho!
- Contact:
Re: Anyone want to know how GPS works?
mine uses batteries.
I am Leader of all The Atheists in the world - FACT.
Come look inside Santa's Hole
You want to hear the truth about Santa Claus???.....you couldn't handle the truth about Santa Claus!!!
Come look inside Santa's Hole

You want to hear the truth about Santa Claus???.....you couldn't handle the truth about Santa Claus!!!
- Eriku
- Posts: 1194
- Joined: Thu Aug 05, 2010 10:19 am
- About me: Mostly harmless...
- Location: Ørsta, Norway
- Contact:
Re: Anyone want to know how GPS works?
What, your fish?
Is it one of those which sing a shitty tune when you clap?
Is it one of those which sing a shitty tune when you clap?
- leo-rcc
- Robo-Warrior
- Posts: 7848
- Joined: Thu Feb 26, 2009 5:09 pm
- About me: Combat robot builder
- Location: Hoogvliet-Rotterdam, Netherlands
- Contact:
Re: Anyone want to know how GPS works?
How can GPS be be used for altimeters?
Best regards,
Leo van Miert
My combat robot site: http://www.team-rcc.org
My other favorite atheist forum: http://www.atheistforums.org
Horsepower is how hard you hit the wall --Torque is how far you take the wall with you
Leo van Miert
My combat robot site: http://www.team-rcc.org
My other favorite atheist forum: http://www.atheistforums.org
Horsepower is how hard you hit the wall --Torque is how far you take the wall with you
Re: Anyone want to know how GPS works?
Sorry this took so long....leo-rcc wrote:How can GPS be be used for altimeters?
"Pseudoranges" (ie the trilateration distance measurements observed earlier) from at least 4 SVs are required for a receiver to compute a 3D fix on a reference ellipsoid, and from there to pretty much any other defined surface, like "Sea level".
The short (and very belated) answer to your question is that your receiver uses a minimum of 2 (3D) triangles.
It's important to remember that the sats are in a dynamic 3D array, and that some geometries are better than others, but they are all transient. GDOP (geometric dilution of precision) is a rough inverse calculation of how well your receiver can resolve its position on the Z-axis at a given time and place. The less dilution, the stronger the geometry. Drink it down.
Re: Anyone want to know how GPS works?
*interrupts*
Nice to see you again, piscator.
*carry on ... *
Nice to see you again, piscator.
*carry on ... *
no fences
Re: Anyone want to know how GPS works?
Do the clocks run slower on the satellites to take account of special relativity. 

“I wish no harm to any human being, but I, as one man, am going to exercise my freedom of speech. No human being on the face of the earth, no government is going to take from me my right to speak, my right to protest against wrong, my right to do everything that is for the benefit of mankind. I am not here, then, as the accused; I am here as the accuser of capitalism dripping with blood from head to foot.”
John Maclean (Scottish socialist) speech from the Dock 1918.
John Maclean (Scottish socialist) speech from the Dock 1918.
Re: Anyone want to know how GPS works?
Pensioner wrote:Do the clocks run slower on the satellites to take account of special relativity.
And who goes up to put them forward an hour in the spring and one back in autumn ?




Give me the wine , I don't need the bread
- Pappa
- Non-Practicing Anarchist
- Posts: 56488
- Joined: Wed Feb 18, 2009 10:42 am
- About me: I am sacrificing a turnip as I type.
- Location: Le sud du Pays de Galles.
- Contact:
Re: Anyone want to know how GPS works?
Midgets.Feck wrote:Pensioner wrote:Do the clocks run slower on the satellites to take account of special relativity.
And who goes up to put them forward an hour in the spring and one back in autumn ?
For information on ways to help support Rationalia financially, see our funding page.
When the aliens do come, everything we once thought was cool will then make us ashamed.
Re: Anyone want to know how GPS works?
Ginger welsh guys do it, do they?Pappa wrote:Midgets.Feck wrote:Pensioner wrote:Do the clocks run slower on the satellites to take account of special relativity.
And who goes up to put them forward an hour in the spring and one back in autumn ?

“I wish no harm to any human being, but I, as one man, am going to exercise my freedom of speech. No human being on the face of the earth, no government is going to take from me my right to speak, my right to protest against wrong, my right to do everything that is for the benefit of mankind. I am not here, then, as the accused; I am here as the accuser of capitalism dripping with blood from head to foot.”
John Maclean (Scottish socialist) speech from the Dock 1918.
John Maclean (Scottish socialist) speech from the Dock 1918.
Re: Anyone want to know how GPS works?
Oh yes... SV clocks need to time sync to within a few nanoseconds to broadcast valid position data to themselves and you, yet they are in a different spacetime curvature zone and have very high velocities relative to your handheld receiver.Pensioner wrote:Do the clocks run slower on the satellites to take account of special relativity.
Relativistic corrections in all 3 segments of the GPS system (space, control, user) make GPS usable. The clock corrections alone enhance the accuracy of your cell phone GPS by a factor of over a thousand.
The pixies are there to help us find meaning in it all
- Orwellian
- Clerk, Records Department, Ministry of Truth
- Posts: 98
- Joined: Mon Jun 13, 2011 12:05 pm
- About me: I am an intellectual, a member of the Outer Party, and I live in the ruins of London. I grew up in the post-Second World War UK, during the revolution and the civil war after which the Party assumed power. During the civil war, Ingsoc placed me in an orphanage for training and subsequent employment as a civil servant. I maintain a squalid existence, living in a one-room apartment, eating a subsistence diet of black bread and synthetic meals washed down with Victory-brand gin. I keep a journal of negative thoughts and opinions about the Party and Big Brother, which, if discovered by the Thought Police, will warrant death, so don't tell on me. I am fortunate, because the apartment I live in has an alcove, beside the telescreen, where it cannot see me, and so my thoughts remain private.
- Location: Airstrip One, Oceania
- Contact:
Re: Anyone want to know how GPS works?
Satellites send signals to the GPS units on the ground Measuring the distances to the known points (the satellites) the relative location of the GPS unit on the ground can be calculated using geometry. Basically, think of an imaginary sphere around the satellite with the satellite at the center. Based on the time it takes the signal to get to the GPS unit, its position on the imaginary sphere can be located. To get the GPS unit's location in 3 dimensional space, you need 4 satellites, I believe. And the location is the position on each of the imaginary circles intersecting at the GPS unit. Or, something like that.piscator wrote:i have a degree in geodesy, so chances are i can answer your questions or bullshit my way through them.
To the future or to the past, to a time when thought is free, when men are different from one another and do not live alone — to a time when truth exists and what is done cannot be undone: From the age of uniformity, from the age of solitude, from the age of Big Brother, from the age of doublethink — greetings!
Re: Anyone want to know how GPS works?
^^ Yeah. What he said! 
'Cept I like to think of a point in space surrounded by ellipses representing the orbits of SVs. This point, by something more than happy coincidence, happens to orbit the sun in the approximate center of Earth's mass and lets clever geomancers originate what they like to call an "Earth-Centered, Earth Fixed" coordinate system shaped something like an elliptic sphere or symmetrical egg.
From a reference surface centered in this coordinate system,, other coordinate systems more closely resembling actual or equipotential surfaces (like sea level) can be derived or translated for a given point in time.

'Cept I like to think of a point in space surrounded by ellipses representing the orbits of SVs. This point, by something more than happy coincidence, happens to orbit the sun in the approximate center of Earth's mass and lets clever geomancers originate what they like to call an "Earth-Centered, Earth Fixed" coordinate system shaped something like an elliptic sphere or symmetrical egg.
From a reference surface centered in this coordinate system,, other coordinate systems more closely resembling actual or equipotential surfaces (like sea level) can be derived or translated for a given point in time.
Who is online
Users browsing this forum: No registered users and 2 guests