Leica Geo Office Tutorial: Using SmartWorx Viva, CSRS-PPP & Geo Office
This tutorial provides an overview of the process involved in working with a Leica Viva Base & Rover on an arbitrary datum, then later updating the coordinates of the base and rover onto a predefined datum using PPP and Leica Geo Office.
Before you begin:
The accuracy of PPP is directly related to the occupation period of the GNSS sensor over the base point. The following link provides detailed information regarding expected accuracies when using the service. http://www.geod.nrcan.gc.ca/products-produits/ppp_acc_e.php
As a general rule of thumb, 40mm 3D accuracy can be achieved after 2 hours of constant occupation over a single point, and the maximum accuracy of around 10mm can be achieved after 12 hours.
PPP will process both GPS and GLONASS data, though it seems that there is a delay of around 24 hours after the survey until GLONASS data can be used in the correction.
Further reading on PPP can be found in the user guide at: http://www.geod.nrcan.gc.ca/userguide/index_e.php
Beginning the survey:
The process for survey is very similar in all Leica instruments capable of logging raw GPS data. If a license for on-board RINEX logging has been purchased, we’d recommend using that functionality as the RINEX file can then be uploaded onto PPP directly from the instrument. If the option has not been purchased, the data needs to first be converted using LGO (this will be covered later in the tutorial).
For this tutorial, I’ve used two Leica GS15 GNSS sensors, and a CS15 controller to communicate with each sensor. First, I’ve enabled data logging on the base sensor by going to ‘Instrument’ > ‘Base Settings’ > ‘Raw Data Settings’
N.B. A 15 second logging rate should be sufficient for PPP.
Start the base using a ‘Here’ (on System 1200, GS09) or ‘Over any point’ (Viva). It’s usually a good idea to check the data logging status on the instrument to ensure that logging has initiated and there is sufficient space on the storage device for data.
You are now able to connect to the Rover and complete the survey as per usual. When the survey is completed, power down the base sensor using the power button.
Uploading the raw data to PPP
On the SD card from the Base Sensor, locate the Rinex (.12o extension found in ‘Data’ > ‘GPS’ > ‘Rinex’) or the Leica raw files (MDB) which are contained in the DBX folder under the job name.
If using RINEX, the files can be uploaded directly onto PPP @ http://www.geod.nrcan.gc.ca/online_data_e.php
If using Leica MDB, the files first need to be converted to RINEX before upload. This can be done in LGO using the following method; Open a new project, then go to ‘Import’ > ‘Raw Data’ select the file type as SmartWorx raw data and select the MDB directory in the window. In the ‘assign’ window, remove any erroneous data and then assign the data to your new project. Rinex can then be exported by using ‘Export’ > ‘RINEX data’, or by a right-click > ‘Export to RINEX’ on any GPS track through the ‘GPS-Proc’ tab.The settings in this screen don’t matter too much, just make sure there is a separate file for each GPS track. This exported data can then be uploaded to PPP.
On the PPP website (sample above) you are able to select the coordinate system and epoch to apply to the output, as well as the email address to receive the results.
Shortly after submitting the files, you will receive an email from NR Can with the processing results. The corrected coordinates and estimated accuracies are contained within the email body, but it’s worthwhile downloading the report link for background and quality assurance. The results from my survey are shown below
Updating the RTK Survey in LGO
Transfer the raw RTK data from the survey controller to the computer using a portable storage device or ActiveSync, then import this data into a new LGO project using the ‘import raw data’ function in the toolbar. Assign the data to the new project, then select the view/edit tab to view the GPS data.
Because all RTK points are referenced to the base point(s), all that needs to updated is the coordinates of the base point, the rover points will then be automatically updated to the corrected coordinates.To do this, right click on the base point (in my example I’ve named it BASE). In the ‘coordinate type’ and ‘coordinate format’ fields, select geodetic and lat/long/height. Enter the lat/long/height from the PPP results, then press OK to update the coordinates.
I’ll now attach a UTM coordinate system and Geoid to the survey by selecting ‘File’ > ‘Project properties’ > ‘Coordinates’ tab, then selecting the coordinate system with geoid attached. In this example I’ve used a UTM10 north with a HT2 geoid. Press OK to confirm.
Finally, I’ve cross referenced the UTM coordinates and orthometric height with those provided on the PPP email in order to check that I hadn’t made a typo in my updated coordinate entry.
The LGO job can now be combined with more TPS/GPS data or exported for use in CAD.
This tutorial will be available as a webinar shortly. For more information or to arrange a demonstration of Leica GNSS or Leica Geo Office, please contact your local Spatial Technologies representative toll free on (877) 252 0070 or for questions or feedback regarding this tutorial, contact Spatial Technologies technical support