CURRENT VERSION - 1.0.4      5 MAY 2008

Waiter's GPS Set Time

GPS_Time - Why?

If you have access to any of the gazillion Time Servers that are available via the internet, you may ask, "What’s Waiter's GPS Set Time going to do for me?"

Well, probably nothing.

But, if you have difficulty connecting via the internet, or, that Time Server you selected keeps changing IPs, etc, then Waiter's GPS Set Time may be a good utility to run, especially if you already have one of those inexpensive GPS Serial receivers. (I've seen them advertised as cheap as $39 from Deluo Electronics, WOW)

The Program

When opened, Waiter's GPS Set Time reads the computers internal clock and continuously displays this on the screen.

After the selected time delay (provides the user time to get the receiver connected, or other programs to start, etc) it starts monitoring the selected serial port, looking for the connected GPS receiver. When valid data is recognized, an indicator (the one on the left) turns bright green to indicate GPS Sentence data is being received.

When the GPS receiver obtains a valid 2D or 3D position fix, the fix indicator light (the one on the right) turns bright green, and the SET TIME button becomes enabled.

Waiter's GPS Set Time screen then displays the GPS Fix Time, Receive altitude (feet or meters), and the receiver position in Latitude and Longitude.

If the SYNC TIME ON STARTUP was selected, then the computers time will be syncronized at this time.

You can view the raw serial data stream by placing your mouse over any of the GPS label items (GPS Time, Latitude, Longitude, or Altitude). The Serial data can then be seen streaming by in a small pop up window.

INSTALLATION

Download and unzip the file GPS_Time.zip, then run the "setup.exe" file.

Waiter's GPS Set Time will install itself and place a shortcut on the Desktop AND in the "Program files/Startup" folder.

When you boot your computer, Waiter's GPS Set Time will startup automatically.

SETTING THE TIME

Waiter's GPS Set Time updates the computers internal clock immediately if the SET TIME button is pressed, OR Automatically at a random time. The random "Next Update" happens at least once during any 24 hour period.

GPS time updates set the computers Time and Date, and take into account the local computers "Time Zone" settings.

You can try this by manually setting the computers Date and Time to some value, then clicking on the SET TIME and see it update to the current GPS Fix Time.

RUNS FROM THE SYSTEM TRAY

To make sure your computer always has the right time, Waiter's GPS Set Time starts when your computer boots up, and continues to run in the system tray. You can select the option to automatically start Waiter's GPS Set Time either on the screen, or in the system tray.

NOTE: If you don't want Waiter's GPS Set Time to start when your computer boots up, goto "START > PROGRAMS > STARTUP", Right click on the Waiter's GPS Set Time selection and choose DELETE.

VERY IMPORTANT NOTE REGARDING GPS FIX TIME

The GPS Time displayed is NOT the ultra accurate GPS Atomic Clock.

The GPS Time displayed is the time that the position fix was calculated inside the receiver. This is normally accurate to Plus/Minus one second of GPS Atomic clock.

If you need more accuracy than this, then you need to be looking at one of the Cesium Atomic Clock accessories that can connect to your computer :-)

USER OPTIONS

All user options are saved in the file GPS_Settime.XML

ALTITUDE

Select either Meters or Feet for the Altitude Display.

STARTUP

Waiters GPS Set Time can be configured for different startup behavior:

START IN SYSTEM TRAY - Starts Waiters GPS Set Time in the system tray.

TIME SYNC AFTER STARTUP - After Waiters GPS Set Time starts, it'll perform a time sync immediately after it receives a Valid Fix from the GPS Receiver.

STARTUP DELAY - When the program is first started, we may want to perform a delay to ensure other programs are started before initializing the serial port. (i.e. virtual port program, etc).

   30 SEC A delay of 30 seconds before the port is initialized.

   No Delay The serial port is initialized after about two seconds.

COMM

Select the serial port parameters These are the standard Port Number, Baud rate, flow, etc, etc,

   PORT - Waiter's GPS Set Time will analyses your computer and only provide you with the com ports that have been detected when the program starts.

If your port is not on the list, OR, you get an error telling you that the port doesn’t exist, then click on the "None/Reset" selection. This will force GPS_Time to go out and reevaluate the comm ports again.

Example : This is useful in the event you changed ports after you started Waiter's GPS Set Time; i.e. plugged in the USB GPS receiver after you started Waiter's GPS Set Time

Click on None/Reset, Your USB serial port assignment will now be in the list.

NOTE: Most computers have several USB plugs Your USB receiver should always be given the same serial port assignment whenever its plugged into the "same" USB port on your computer. However, if you plug your receiver (or USB-Serial converter) into a different USB port (i.e. multiple ports or a "hub"), then it will be given a different serial port for that USB port.

SETTING TIME ON YOUR NETWORK.

Once you have Waiter's GPS Set Time installed and running on your computer, You can tell other computers on your network to set their time to this computer.

Windows has a command called "Net Time" You can read about it on the Microsoft Knowledge Base article 314090.

I leave my home computers running 24/7, so I created a batch file (SETTIME.BAT) and placed it in the root directory of each of the other computers on my network. I then use Windows Scheduler to run the batch file once a day in the early morning.

The Batch file is a one line script:

net time \\192.168.10.1 /set /yes

or

net time \\GPS_Computer /set /yes

The "IP address" or "GPS_Computer" is the address or name of the computer that has the GPS receiver attached and is running Waiter's GPS Set Time.

When the SETTIME.BAT file runs, it connects to the computer specified, and syncrinizes the local computers time/date to the time/date that is on the remote machine.

GPS THEORY - Where Am I?

A GPS Receiver computes its position by calculating the distance from numerous satellites, then triangulating these distances to calculate a three dimensional position referenced to a standard earth model (usually WGS84 datum).

In order to navigate, you only need two items; 1) An accurate clock, and 2) you need to know the position of your reference (Satellite, star, etc)

Each Satellite transmits a continuous data stream. This data stream includes many components, two of which are a time stamp of when the transmission took place, and, highly accurate data as to the orbital parameters of the individual satellite.

The Time stamp comes from an on board clock. This clock is very accurate (1 part in a billion) and is synchronized with all the other GPS satellites.

The Satellite Orbital parameters, along with the clock are used to very accurately calculate the position of the satellite. This is done in the receiver when it receives the GPS signal.

Waiter         (Waiter (at) iflyez (dot) com)