## 6 Positioning Analysis
### NRCan PPP Results
Except for the 8 mm difference in the TRM5 due to using data from different days, the agreement of the \(L_{IF}\) PCOs indicates the successful implementation of the manual PCV correction to the input RINEX observations. Since no official calibrations are freely available for the remaining antennas, they could not be compared against an absolute reference. However, by accounting for the different adaptor heights, the height estimations can be compared. Figure 5 shows the height offsets from the GPS pillar reference point using the original data without supplying the antenna type in the RINEX header and after correcting the RINEX data with the estimated PCV corrections in 0.1\({}^{\circ}\), 1\({}^{\circ}\), and 5\({}^{\circ}\) resolution. Since we compare with a known height and do not apply corrections for the PCO, the observed height offsets can be interpreted as an \(L_{IF}\) PCO estimate. The first aspect to note is the height difference with and without applying receiver antenna PCV corrections. For the LEIAR antenna, the difference is 18 mm, whilst the TRM5 antenna demonstrates almost no changes (between 0 and 4 mm) with or without the PCV correction. It means that the phase variations from the TRM5 antenna must be close to a circular constant phase pattern, while the LEIAR and other antennas apparently deviate more from a circular pattern, which eventually results in the observed height offset. It is known that radomes, such as the one used by the LEIAR, can have an impact on the station height of several cm (see also [20]). Moreover, the effect of applying PCV corrections is much higher for both lower-cost antennas (AV28, ANN-MB) than for the more expensive antennas (LEIAR, TRM5, and GA530). The lower-cost antennas AV28 and ANN-MB are characterized by high offsets of 92 and 66 mm before applying the PCV corrections. After \begin{table}
\begin{tabular}{l c c} \hline \hline
**Antenna/Case** & **LEIAR** & **TRM5** \\ \hline No antenna PCO/PCVs [mm] & 183 & 71 \\ Automatic ICS PCO+PCV [mm] & 0 & \(-8\) \\ Manual IGS PCV-only [mm] & 167 & 72 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Height differences for three different scenarios of handling antenna calibrations. The reference is the estimated height for the LEIAR antenna, with IGS ANTEX corrections (5\({}^{\circ}\) angular resolution) applied automatically by the PPP. See the text for a more detailed explanation. applying the corrections, the estimated \(L_{\text{IF}}\) PCOs are reduced to 26 and 39 mm, which appear rather reasonable. Interestingly, when a rectangular adaptor is utilized, the offsets are of opposite sign but in the same order of magnitude of approximately \(-\)70 mm before calibration. After calibration, they are reduced to around the same level as the results with a circular ground plane with offsets of 31 and 28 mm. In particular, the fact that the offsets with the same antenna but with different mounting adaptors differ between 17 and 14 cm before correction and only up to 1 cm after the correction appears promising. The results for various resolution bins (averaging width) do not vary significantly, with values between 1 and up to 4 mm, except for the GA530 antenna and AV28 antenna with a rectangular adaptor in combination with a bin size of 5\({}^{\circ}\). The latter could be due to a measurement outlier or caused by substantial PCV differences, presumably caused by the near-field effects on the edges of the rectangular adaptor, which might be better represented at the finer scale but may behave poorly in the case of the 5\({}^{\circ}\) averaging method.