Introduction

An analysis will be performed on the survey conducted with Trimble R12i in RTK mode using all available GNSS constellations and signals. This analysis will focus on the reliability that each point offers in a localized geometric context.

 

Fig 1. Topographic survey, view from observed baselines

 

Some statistics

125 baselines were observed, allowing the determination of the coordinates of each point, thus creating a sufficiently detailed topographic representation for the intended purpose, in a total time of 28 minutes and 24 seconds.

Each point was determined using the rapid point methodology, therefore, the results can be improved by implementing a topographic point.

Table 1. Productivity Report

 

 Below is a statistical summary of the survey:

  Horizontal Precision (m) Vertical Precision (m) Satellites Tilt Distance (m)
Mean 0.0230 0.0312 22.7 0.7060
Std. Dev. 0.0066 0.0079 3.2 0.2549
Maximum 0.0459 0.0541 27 1.3998
Minimum 0.0124 0.0208 14 0.2265

Table 2. Statistical summary

 

COMPARING GEOMETRIES

Simple and perfect geometries will be considered (this may not be the case); therefore, the comparison is based on the R12i's ability to correctly relate different geometries.

Reobserved points

Table 3. Comparison of reobserved points

    Lines

    Fig 2. Observed lines

     

     Line Number of points Root Mean Square Error (m)
    1 4 0.0253
    2 4 0.0207
    3 4 0.0052
    4 4 0.0136

    Table 4. Root mean square error in line adjustment

    Arcs

    Fig 3. Observed arcs

     

     Line Number of points Root Mean Square Error (m)
    1 9 0.0769
    2 8 0.0256
    3 8 0.0868
    4 10 0.0902
    5 12 0.0379

    Table 5. Root mean square error in arc adjustment

     

     

    Conclusions

    A series of observed geometries were analyzed based on a set of points whose coordinates were determined using rapid point. Furthermore, it is assumed that the geometries are perfect and that it is the points that introduce some noise (which is not correct, but is considered this way to simplify the explanation).

    The results obtained can be considerably improved by applying a technique that offers greater precision. For this, the use of the topographic point technique is recommended.

     

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