Data Deposition for Article: 'Measurement of the Earth Tides with a MEMS Gravimeter'
Summary of Files:
There are 9 files included in this data deposition.
The first batch of 9 files are the data files and those used to process the data:
Four of these are experimental data files: 'voltage_and_temperatures', 'test' and 'regressed data'.
There is also a file that includes the theory data for the tides in Glasow: 'Tidal_Correction_10Mar_15days'.
There are also two files, 'Data Analysys', and 'Data Analysis 2' that processes the previous four files and plots the graphs.
'Mregg' is also called as part of 'Data Analysis' - this is a cub code (not written by us) that is used to do the regressions.
Another file, 'triple PID_020215' is the Labview PID controller used to read in data from the 5 thermometers, the MEMS displacement signal,
and the intensity monitor. Three of these thermometers have a feedback PID mechanism in this code: MEMS temp, sheild temp, and plate temp.
More Detailed description of data and analysis files:
'Voltage_and_temperatures'consists of 8 columns of data.This data was taken from the 13/03/15 to the 18/03/15
Column 1 is the time in seconds from the the start of the measurement.
Column 2 is the temperature of the plate on which the shadow sensor sits.
Column 3 is the temperature of the LED of the shadow sensor
Column 4 is the temperature of the MEMS
column 5 is the temperature of the sheild
column 6 is the temperature of the room
column 7 is the voltage output of the system (a metric for the displacement of the MEMS proof mass)
column 8 is a metric of the photodiode intensity.
'tilt'consists of 3 columns of data. This data was taken from the 13/03/15 to the 18/03/15
Column 1 is the time in seconds from the the start of the measurement.
Column 2 is x-axis tilt of the vacuum tank
Column 3 is y-axis tilt of the vacuum tank
'test' is a data set containing two columns.
Column 1 is the time in seconds from the start of the measurement,
Column 2 is the voltage output from the MEMS displacement sensor.
'regressed data' is a data set containing two columns.
Column 1 is the time in Days from the point 00:00hr on the 10th March 2015.
Column 2 is the acceleration data of the MEMS device, after it has been regressed to remove the effect of temperature, intensity and drift correlations.
'Tidal_Correction_10Mar_15days'
Is a data set produced from Micro-g Lacoste's software: Quick Tide Pro.
It is the tidal signal (including ocean loading) for our location at Glasgow University.
Column 1 is the year.
Column 2 is the day of the year.
column 3 is the time in hour:min:second format
column 4 is the BergerCorrection in micro-Gal
column 5 is the Berger ocean loading correction in micro-Gal
column 6 is the combined berger correction in micro-Gal (this the column that we use for the tidal prediction)
'Data Analysis' is a Matlab File that processes the above data files.
The code is commented but a rough outline is as follows:
It starts by reading in the three data files and interpolating the time series where necessary
so that all data sets can be plotted on the same axis.
It then plots the temperature variations for all of the recorded temperatures.
A regression is then performed against chosen parameters to remove any correlated trends between these parameters and the experimental data
Figure 3 is a plot of the regression fit, followed by the data with this fit removed
Figure 4 plots the experimental data from the previous lower subplot, and also plots the theoretical tide data next to this.
Figure 5 is a histogram of 10000 randomised experimental data sets, this is used to calculated the significance of the correlation between theory
and experimental data.
Figure 6 is a plot of all of the regressed parameters
Figure 7 is the allan deviation of the data.
figure 8 a plot of the power spectral density of the data.
To get the full, unsmoothed data as is plotted in the tide figure in the paper, 'down' must be set to 1, and 'NSG' set to 2. Other values of NSG remove various different correlations
'Data Analysis 2' is a matlab file that processes 'test'
This plots another ampluitude spectral density for the MEMS gravity sensor.
Since test contains high frequency data, this plot is over a higher frquency range that that plotted in figure 6 from 'Data Analysis'.