Site Survey with WinOnCore
 WinOnCore  |  Start WinOnCore  |  Subwindows  |  GPS Self-test  |  Initialization  |  General Setting  |  Timing Setting  |  Survey Setting  |  Save Survey  |  Advance Technique  |  Links 


WinOnCore

WinOncore is a software package designed for use with Motorola's Oncore GPS receivers. It is used with our UT Plus OnCore Timing Module to displaying, plotting and printing data from the receiver; and recording and replaying data files.
The main purpose of WinOncore is to determine the position of our user segements (i.e. the position of the Oncore Timing 2000 Antennas of our user segments) in our project. All schools have to perform the site survey with WinOnCore and their results will be used in our Data Acquisition Program to determine the timing of the collected data.
In this webpage, you will find the procedures of the site survey with WinOnCore for our project.

Start the WinOnCore Program

There should be an icon for WinOnCore on the desktop of the computer. Double click on it to start the program. The WinOnCore should be started with the following seven subwindows opened: Signal Quality, Azimuth & Elevation, Survey, Navigation, Commond Monitor, Additional Message and Timing Windows.


Subwindows

In our project, the following seven subwindows are usually opened to monitor the performance of the GPS timing module.
1. Signal Quality Window: The Signal Quality Window displays all of the channel dependent data. This display includes a bar chart representation of the signal strength.

2. Azimuth and Elevation Window: The Azimuth and Elevation Window contains a skyplot of all visible satellites according to their elevation and azimuth. The Satellite Info tab displays information for each satellite including the PRN, Doppler, elevation and channel status of all the visible satellites. It also shows the signal strengths for the satellites currently being detected and lists any ignored satellites and the mask angle.
The skyplot only shows visible satellites after an almanac has been loaded into the receiver and the receiver must also be sending the Satellite Visibility (@@Bb) message to update any information in the Azimuth & Elevation Window.

3. Survey Window: The Survey Window displays the 2-dimensional survey path (latitude vs. longitude), altitude (GPS height) path and statistical information on the position average.

4. Navigation Window: The Navigation Window displays the date, time, position data, receiver status and visible satellite status. This information is extracted from the Position/Status/Data Message (@@Ea).

5. Command Monitor Window: The Command Monitor Window displays all commands sent (TX) to and received (RX) from the Oncore UT Plus Timing Module.

6. Additional Message Window: The Additional Message Window acts as a direct communication link with the timing module. All commands can be sent from the command line of this window. The response is displayed in the bottom area.

7. Timing Window: The Timing Window displays most of the data from the Time RAIM Setup and Status Message (@@En and @@Hn). There are two tabs in the Timing Window. The Time and TRAIM Status tab displays the TRAIM Status, Time and Oscillator and Clock Parameters. The Negative Sawtooth tab displays the negative sawtooth time error of the next 1PPS pulse as a line graph.

All of these windows can be opened, closed, or resized as an normal Microsoft windows. If any of them has not shown up at the starting of the WinOnCore, it can be opened by its corresponding icon on the Toolbar.
Signal Quality Window
Azimuth and Elevation Window
Survey Window
Navigation Window
Command Monitor Window
Additional Message Window
Timing Window

GPS Self-test

A Self Test Dialog is activated through the button . Click the Initiate Test button to start the Self Test. The self test may take several seconds to complete and a progress box will indicate the percentage to completion. The results of the Self Test Dialog should be the same as the one shown below.

If there is no problem with the timing module, click the OK button to close the Self Test Dialog.

Initialize the Timing Module

The WinOnCore is probably taking data in position hold mode when it is started. However, in order to have a consistent approach of site survey for all schools, we will reinitial the timing module.
Click the Set to Defaults button to reset WinOnCore and the timing module. Click the Yes button to proceed the factory reset.
Click the Setup Receiver button to setup the timing module. Click the Yes button to proceed the setup.
In the Communications Settings Dialog, select Comm 2 for the Comm Port and 9600 for the baud rate. Click the OK button to continue.

In the Position Dialog, enter 22'25" for latitude, 114'12" for longitutide and 0 for the altitude. Select the North and East radio button. Click the OK button to continue.

In the Set Time, Date and GMT Offset Dialog, the Local Time and Date are entered automatically by the computer. Make any necessary correction if the data or time is incorrect. Select +8 hours for the GMT Offset and click the UTC Time radio button for Time Mode. Click the OK button to continue.

In the Output Message Rate Dialog, enter 1 for the output message rate. Click the OK button to continue.

Click the OK button to finalize the receiver setup.
The timing module is now reset to the factory default and the satellites' tracking information must be reloaded from the satellites before the timing module to start the site survey. This might take about 15 minutes to over an hour depending on the view of the GPS antenna. Please be patient if no satellite is detected at the moment.

General Settings

Select Options > General Settings in the Option Menu to open the General Settings Dialog. Choose Metric for the Units of measure and ddd"mm'ss.sss for the Position Format.


Timing Settings

Select Options > Timing Settings in the Option Menu to open the Timing Dialog. Enter 3 for the TRAIM Alarm Limit and check on the TRAIM Enabled box the enable it.


Position Survey Settings

Right click on the Survey Window and select Enable Least Square Fit Average Indicator and Enable Position Average Indicator to enable them if the check marks are not indicated on the left side as shown below.

Right click on the Survey Window and select Properties to open the Survey Window Properties Dialog. Enter 12 for the DOP Threshold in the Lat/Lon/GPS Height Average Calculations Option.

The WinOnCore is now ready to collect data from the timing module and perform site survey. It will take over a few hours for a good survey. Please come back in the next day to collect the survey results.

Save the Site Survey Results

Select File > Save As in the File menu and save the path file.
Resize the Survey Window to maximum (by clicking the square on the upper right corner of the window). Resize different sections of the window for a comfortable view by using mouse. Hit the Print Screen Sys Rq button on your keyboard to copy the screen to clipboard. Open Paint (Start > Programs > Accessories > Paint ) and paste the sceen copy into it. Save the file.
Email the files to
yylee@phy.cuhk.edu.hk.


Advance Technique for Site Survey

The approach for site survey listed about should give good results (within 15 meters) for most of our GPS modules. However, some of the schools have not a complete view of the sky. They might have trouble with their survey results and the standard deviations of the calculated positions are very large (over 20 meters). These are probably due to some positions calculated from reflected signals which makes the calculated position far away from the actual one and contribute a large error to the result. It is possible to remove those data if we select the data ourselves and compute our own results.
In order to record the position obtained by WinOnCore in a readable format, enter RECORD PS8 in the Additional Message Window after WinOnCore starts the site survey. Enter RECORD PS8 C to stop the recording when there is enough data (about one day shoule be enough). There should be a new file with extension PS8 (yymmdd01.ps8) written in the directory C:/Program Files/Motorola/WinOnCore12/.
Download the following program
SiteSurvey.exe and put it in the same directory as the PS8 file. Rename the PS8 file as survey.ps8 and double click on the SiteSurvey.exe to run it. It will calculate a better survey result by removing bad data and save the results in a new file survey.out.

Relatied links

Global Positioning System and the Telescope
WinOncore12