MAGNET Tools: Items to check when comparing your solution to an OPUS solution

Items that need to be checked and configured correctly to get a result that matches OPUS

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MAGNET Tools: Items to check when comparing your solution to an OPUS solution

Many surveyors use NGS’s OPUS solutions to validate their post processing software.

When comparing post processed solutions from MAGNET Tools with an OPUS solution there are some items that must be set up correctly to arrive at the same solution.

When uploading your data to OPUS it is important that the correct antenna is selected. 

Pay particular attention if you are using the 100 mm spacer as a part of your set up. Use of the spacer changes the antenna model for OPUS.

Note the two different choices shown to the right.

TPSHIPER_SR NONE is for a Topcon HiPer SR without a radome.

TPSHIPER_SR+10 NONE is for a Topcon HiPer SR with the 100 mm or 10 cm spacer without a radome.

Use of the 100 mm spacer changes how the ARP height is computed for OPUS.

TPSHIPER_SR NONE is for a Topcon HiPer SR without a radome.

Note the ARP is at the bottom of the antenna.

Use of the 100 mm spacer changes how the ARP height is computed for OPUS.

TPSHIPER_SR +10 NONE is for a Topcon HiPer SR with the 100 mm or 10 cm spacer without a radome.

Note the ARP is at the bottom of the spacer.

Many of Topcon’s receivers have separate antenna calibrations for use of the spacer.

These calibration drawings can be found here.

All Antenna heights in OPUS are vertical heights in meters.

Any slant heights taken in the field will need to be corrected to vertical and then to the Antenna Reference Point (ARP) selected in OPUS

When CORS data is automatically downloaded in MAGNET Tools the position supplied in the data is for the L1 phase center of the antenna.

MAGNET Tools works with positions from the ARP. Before processing GNSS data the position of the CORS station must be adjusted to reflect the ARP position of the CORS station antenna.

The correct coordinates can be found on the NGS data sheet for the CORS Station.

CORS station data sheets can be found here

These coordinates can be changed by right-clicking the point in the points tab in the lower portion of the screen and selecting Properties.

Then press the Coordinates tab and enter the correct coordinates for the ARP for the station.

Do this for each CORS station being used.

Select the Process tab on the ribbon.

Press GPS+ PostProcessing.

Press Adjustment.

You are now ready to compare the coordinates from your OPUS solution and those derived from MAGNET Tools.