JAVAD TRIUMPH-LS Short Baseline Accuracy and Precision with 1 Hz and 5 Hz Corrections

By Matt Johnson

In a previous article, “JAVAD GNSS 5 Hz “Beast Mode” RTK Base Station Corrections Reduce the Time to Acquire a Fix by 72 Percent,” the benefits of RTK base station correction rates greater than 1 Hz were discussed. This article will investigate and compare the accuracy and precision of JAVAD TRIUMPH-LS RTK positions with a JAVAD TRIUMPH-2 base station with both 1 Hz and 5 Hz corrections in an open-sky environment with a short baseline.

Procedure

A TRIUMPH-LS RTK rover and TRIUMPH-2 base station were set up on tripods in a farm field. The base and the rover were adjusted to be at the same height as checked with a 4-foot level. The horizontal distance between the base and rover was measured with a tape measure to be 2.93’.

A TRIUMPH-2 and TRIUMPH-LS set up on tripods in a farm field as the sun sets in the background.

Using the TRIUMPH-LS’s field software, J-Field, the TRIUMPH-LS was configured to automatically accept collected points and continuously collect points until manually stopped.

“How to Stop?” configuration screen in J-Field set to collect 10 epochs, Auto Accept points and Auto Re-Start.

Six sessions of points were collected: points with 10, 30 and 60 logged epochs with both 1 Hz and 5 Hz corrections rates. The RTK engines were configured to automatically reset after each point was collected.

Results

Analysis

• All points had good horizontal precision and 95.4 percent of all points (2 standard deviations) fell within 0.027’ of the average position in the worst group of “1 Hz 10 Epochs.”
• The point groups had good horizontal accuracy. The physically measured distance between the base and rover matched the averaged RTK groups’ position within 0.014’.
• All points had good vertical precision and 95.4% of all points (2 standard deviations) fell within 0.052’ of the average position in the worst groups of “1 Hz 60 Epochs” and “5 Hz 10 Epochs.”
• The point groups had good vertical accuracy. The base and rover were set up at the same height. The error between the averaged heights of the groups was at most 0.041’.
• The vertical precision tended to improve as the number of epochs collected increased. The horizontal precision had marginal improve as the number of epochs collected increased.
• The base station broadcast rate does not appear to have any substantial effect on the precision but allowed points to be collected with less time. With 1 Hz corrections, a point with 60 epochs requires 60 seconds to collect, but with 5 Hz corrections, it only requires 12 seconds to collect.

Conclusion

In an open sky environment with a short baseline, the RTK position precision is only marginally improved as more epochs are collected. Higher RTK broadcast rates made possible with JAVAD RTK systems allow points to be collected faster.