Sponsored Content
Top Forums UNIX for Dummies Questions & Answers Timekeeping in Linux question ... Post 302517316 by Perderabo on Tuesday 26th of April 2011 12:09:14 PM
Old 04-26-2011
Precise timekeeping is how GPS work. The satellite knows very exactly where it is and what time it is. It sends you a signal and you know when you recieved it. That enables you to draw a sphere around the satellite and you know that you are on the sphere. Do that with a second satellite and you have two spheres which intersect on a circle. Now you know that you are on that circle. A third satellite will have a sphere that intersects that circle at 2 points. A fourth satellite will have a sphere that intersects one of the 2 points. And you are on that point. This over-simplifies the process but it's close enough to give an idea of how it works. Each satellite has several atomic clocks on board and the US Naval Observatory scans each satellite once a day and possibly adjusts them to keep them synced with the USNO Master Clock.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

linux newbie question...

I'm running Vector Linux on this computer, and everythign works fine, except for the NIC. I run netconfig, and then when I reboot it says: DC21140 at 0x9400(PCI BUS 0, device 11) h/w address 00:00:C0:2E:13:dC, and reqquires IRQ 9(provided by PCI BIOS) Setting up net subsytems. ... (5 Replies)
Discussion started by: Corey
5 Replies

2. UNIX for Dummies Questions & Answers

Timekeeping problem

Hello everyone I am currently exploring the different time keeping commands in linux. and I having a lot of trouble figuring out the advantages and disadvantages of using daytime command rdate and hwclock and such commands. Can someone link me to good articles or just give me the answer (5 Replies)
Discussion started by: maniac173
5 Replies

3. UNIX for Dummies Questions & Answers

Linux LVM Question

I've three partitions on /dev/sda: sda1, sda2 sda3. There is FREE space between sda2 and sda3 and sda3 ends on the last sector. sda2 and sda3 have the same number of sectors allocated and so are the exact same size. /dev/sda2 is already part of the VG VolGroup. However, what puzzles me is that... (0 Replies)
Discussion started by: Devyn
0 Replies

4. Linux

(ASK) Question about linux network...

hi all, im linux nubie n want to ask, 1. how to access the windows pc? if from windows to windows, we can use : start-run-\\192.168.1.1\e$ now, how about from linux (fedora) n want to access to windows drive? if I use ssh from linux to windows, ssh 192.168.6.171 ssh: connect... (6 Replies)
Discussion started by: busoh.sensen
6 Replies

5. UNIX for Dummies Questions & Answers

linux installation question?

Hi I accidentally installed another operating system after I had installed Linux and now I can no longer access your Linux system.any solution? Thanks (1 Reply)
Discussion started by: adam25bc
1 Replies

6. Shell Programming and Scripting

New to Linux, have some simple question

Hi All, Here is the problem: I have done a c++ code in Visual Studio 2010, it's a simple project that only have one main function which takes 2 parameters: an integer and a file that stores data. Now, I am asked to write a shell script in linux to execute my main function. I asked my professor... (1 Reply)
Discussion started by: EasonRU
1 Replies

7. UNIX for Advanced & Expert Users

Linux fdisk question (Oracle Enterprise Linux)

OS: Oracle Enterprise Linux 6.2 Hypervisor: VMWare workstation 9 I created a VM and attached a 7gb virtual disk to it. Using fdisk , I partioned the disk like below. The filesystems mounted on this is working fine. But I am seeing the message Partition n does not end on cylinder boundary.... (2 Replies)
Discussion started by: kraljic
2 Replies

8. Linux

Question on Linux Binary

Hi All, On linux system copied a /bin/kill to /bin/killlatest, when i tried to kill a command using /bin/killlatest it is failing with below errors /bin/killlatest 12345 ERROR: no "killlatest" support. Please help on this.. My ideas is to write a wrapper over killl command to find out who... (5 Replies)
Discussion started by: sridhar8183
5 Replies

9. UNIX for Dummies Questions & Answers

New to Linux scripting question

hello i am new to scripting and Linux in general. i am going to school for sys admin and i will need at least some knowledge on scripting. i have been so far ok with learning basic scripting now i am stuck. with a assignment that i was given it was create a script that will tell you if a number... (2 Replies)
Discussion started by: dragonwrench
2 Replies

10. UNIX for Dummies Questions & Answers

Linux question on directories..

Hi, First server every thing is working but keeps crashing so to be on the safe side created second server and moved all the files. But I notice there is a " dot " at the end. See below. Not sure what that means. Also getting 403 on Apache. Please see below. Thanks you so much. ls -l... (4 Replies)
Discussion started by: samnyc
4 Replies
seesat5(1)						      General Commands Manual							seesat5(1)

NAME
       seesat5 - provides satellite visibility information.

SYNOPSIS
       seesat5 [ report ] [ go <Label> ] | [ <command> ... ]

DESCRIPTION
       This  program uses the sgp4 algorithm provided by NORAD to produce position information on a satellite. Seesat5 can produce tracking infor-
       mation for one satellite over a period of several days, or for a collection of satellites over that period. By providing filter	conditions
       seesat5 prints out only those satellites you might have a chance to see rather than all the satellites that pass above the horizon.

       Seesat5	is  typically  run  by placing control commands into an init file called SEESAT5.INI. See seesat5 (7) for the description of these
       commands.  If there is no init file Seesat5 will present the operator with a '>' prompt where commands can  be  entered.  From  the  prompt
       seesat5 will begin analysis when sufficient parameters have been entered to begin the run.

       Seesat5	uses  selection  conditions to filter the data so that only high and bright satellites are printed. Note that the selection condi-
       tions are used to select whether or not the current passes data will be printed. If it is printed, then the complete pass data is  printed.
       ie. all data from when the satellite comes over the horizon until it goes below.

       For lines that satisfied ALL the selection conditions, a "+" sign is printed as the first character.

   Options
       report This  option  will disable printing of report records in the output of the run. These include all command lines found in SEESAT5.INI
	      or entered from the command line or the prompt.

       go     Followed by a label, this option causes branching within the SEESAT5.INI to begin execution at the line following  label.  Branching
	      occurs when the cmdline command is executed in the SEESAT5.INI file.

       command
	      Most of the commands that can be found in SEESAT5.INI can be entered on the command line. If you desire the SEESAT5.INI file to exe-
	      cute after the command line be sure to make the last command RET.

FILES
       SEESAT5.INI
	      The control file for seesat5

       *.tle  Two line element files used by seesat5.

SEE ALSO
       seesat5(7), SEESAT5.INI(5), tle(5), cr(1)

BUGS
       Seesat5 is not always able to check data integrity. Since computation and output is driven by the data in  the  two  line  element,  subtle
       errors  in  a  tle can cause floating point exceptions. In addition there are several commands that do not work well together, like SHOWTLE
       and RUNTIME. Please report any problems with seesat5 to Dale Scheetz <dwarf@polaris.net>.

Debian Linux							    28 March 96 							seesat5(1)
All times are GMT -4. The time now is 02:41 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy