Check reported tracker position vs. theoretical

[AdamRJensen]

The following four angles are returned from the Solys2 tracker:

• Azimuth_adjust

• Zenith_adjust

• Azimuth

• Zenith

• Read the Solys2 documentation to find the definitions of these angles.

See also #70

[AdamRJensen]

Here is one example day:

mask = (df.index > '2020-06-01') & (df.index < '2020-06-03')

fig, axes = plt.subplots(nrows=2, sharex=True, figsize=(6,6))
solpos.loc[mask, 'azimuth'].plot(ax=axes[0], label='Theoretical')
df_qc.loc[mask, 'Azimuth'].plot(ax=axes[0], alpha=0.5, linestyle='--', label='Solys2')
df_qc.loc[mask, 'Azimuth_adjust'].plot(ax=axes[1])
axes[0].set_ylabel('Azimuth')
axes[1].set_ylabel('Azimuth_adjust')
axes[0].legend(loc='upper right')

Here is a histogram of Azimuth_adjust, which I assume to be a correction factor in degrees:

[AdamRJensen]

The theoretical (calculated) position and that reported by the Solys2 tracker can be investigated as such:

azimuth_difference = df_qc['Azimuth'] - solpos['azimuth']
zenith_difference = df_qc['Zenith'] - solpos['apparent_zenith']
azimuth_difference[(df_qc['Azimuth']!=0)&(solpos['elevation']>0) & (azimuth_difference.abs()>1)].index.to_series().dt.date.value_counts()

For the Zenith angle, the above code 831 minutes whereas the Azimuth angle flagged 1010 minutes. Considering this very low number for 10 years of data, I do not see any reason to make corrections or flag data based on the reported angles.

Note, I investigated some of the worst days and they had DNI, hence they could not actually be a full degree off.