Author: Joe Wragg
\centerline{Project Members: Joe Wragg and Stefan Harban} \centerline{Project Supervisor: Professor Andrew Blain}
Malaysia Airlines Flight 370 (MH370) was a scheduled international passenger flight that disappeared on the 8 of March 2014 while flying from Kuala Lumpur Airport, to Beijing. The aircraft has not been recovered, and the cause of the disappearance remains unknown.
Malaysia Airlines Flight 370 (MH370) was a scheduled international passenger flight that disappeared on the 8 of March 2014 while flying from Kuala Lumpur International Airport to Beijing Capital International Airport in China. The aircraft has not been recovered, and the cause of the disappearance remains unknown. It remains the most expensive search and became the biggest mystery in aviation history
Analysis of satellite communications between the aircraft and Inmarsat’s satellite communications network concluded that the flight continued until at least 08:19 and flew south into the southern Indian Ocean, although the precise location cannot be determined. From October 2014 to January 2017, a comprehensive survey of 120,000 km (46,000 sq mi) of sea floor south-west of Perth, Western Australia, yielded no evidence of the aircraft. In January 2018, a second search has been announced to be conducted by a searching vessel provided by private U.S. marine company Ocean Infinity.
In a previous search attempt, Malaysia had established a Joint Investigation Team to investigate the incident, working with foreign aviation authorities and experts. Malaysia released a final report on Flight 370 in October 2017.
The analysis of communications between the flight and Inmarsat’s satellite telecommunication network provide the only source of information about the flight’s location and possible in-flight events after it disappeared from radar coverage at 2:22am.
The main objective of our investigation was to replicate inmarsat’s analasis of the satelite communications and attempt to make our own conclusions. To see if they agree with the established findings given in the report published in october 2017.
\newpage
Our first task was to attempt to find information about the plane’s whereabouts before its dissaperrance from miliatry radar. From there we have a starting point to then analyse the satelite data. Here is what know from the report:
- Malaysia Airlines Flight 370 departed Kuala Lumpur International Airport at 16:41 UTC on the 7th March 2014.
- The final automatically transmitted position (ACARS) from the aircraft occurred at 17:07
- No radio communications were received from the crew after 17:19
- ACARS reports from the flight, giving heading and speed, were expected at 17:37 and 18:07 but were never received.
- At 17:21, the aircraft disappeared from the radar of air traffic control in the South China Sea between Malaysia and Vietnam.
- The aircraft continued to be tracked by Malaysian military radar
- At 1725 the aircraft deviated from the flight-planned route turning around and crossing the Malay Peninsula.
- Flight 370 left the range of Malaysian military radar at 18:22 and was last located 370 km northwest of Penang.
Here is the path predicted in the ATSB “Underwater search areas” report:
\begin{figure}[] \centering \includegraphics[width=\textwidth]{wide.png} \caption{MH370 flight path derived from primary and secondary radar data} \end{figure}
\clearpage
Unfortunately little information is given in the report. The table below shows what information is given in the report and what is needed to be calculated.
\begin{table}[h] \centering \label{my-label} \caption{Table of path variables} \begin{tabular}{|l|l|l|l|l|} \hline \textbf{Location} & \textbf{Tiime(UTC)} & \textbf{Latitude} & \textbf{Longitude} & \textbf{Bearing (deg)} \ \hline KIA & TakeOff & 2.7 & 101.7 & \ \hline Last ACARS & 17:06:43 & 5.27 & 102.79 & \textit{\textbf{A}} \ \hline Last Radar Contact & 17:21:13 & \textit{\textbf{X}} & \textit{\textbf{Y}} & \ \hline Telephone Contact & 17:52:27 & 5.2 & 100.2 & \ \hline Last Military Radar Contact & 18:22:12 & 6.65 & 96.34 & \ \hline \end{tabular} \end{table}
\begin{minipage}{.55\textwidth} The bearing A is calculated in the code by taking the line between the last ACARS position and the KIA position. Then the lat, lon and bearing at last ACARS along with the time difference between last radar and last acars. Can be used to estimate X and Y. Assuming a constant speed of 450 knots.
\medskip The latitude and longitude of the airport can be calculated from the xyz given in the report. These values are in an earth fixed coordinate system and can be converted into latitude and longitude points in the code.
\medskip See appendix figure \ref{table1} \end{minipage} \hspace{.05\textwidth} \begin{minipage}{.4\textwidth} \centering \includegraphics[width=\textwidth]{bearing.png} \captionof{figure}{Figure Showing bearing A 25 degrees} \end{minipage}
\pagebreak
\begin{figure}[h]
\centering \includegraphics[width=\textwidth]{InitialPath.PNG} \caption{Google earth preview of initial path} \end{figure}
Once we plotted this in google earth you can see the result in the image below:
The analysis of communications between the flight and Inmarsat’s satellite telecommunication network provide the only source of information about Flight 370’s location and possible in-flight events after it disappeared from radar coverage at 2:22am.
\begin{table}[h] \centering \label{my-label} \caption{Table showing the seven handshakes} \begin{tabular}{lllll} \textbf{Time (MYT)} & \textbf{Time (UTC)} & \textbf{Initiated by} & \textbf{Name (if any)} & \textbf{Details} \ 2:25:27 & 18:25:27 & Aircraft & 1st handshake & A 'log-on request' message. \ 3:41:00 & 19:41:00 & Ground station & 2nd handshake & Normal handshake \ 4:41:02 & 20:41:02 & Ground station & 3rd handshake & Normal handshake \ 5:41:24 & 21:41:24 & Ground station & 4th handshake & Normal handshake \ 6:41:19 & 22:41:19 & Ground station & 5th handshake & Normal handshake \ 8:10:58 & 0:10:58 & Ground station & 6th handshake & Normal handshake \ 8:19:29 & 0:19:29 & Aircraft & 7th handshake & A 'log-on request' from the aircraft\ \end{tabular} \end{table}
\begin{minipage}{.55\textwidth} The burst timing offset (BTO) is the time difference between the start of the time slot and the start of the transmission recieved from the aircraft. The time it takes for the signal to traverse the following: \begin{itemize} \item Ground station's signal to satelite \item Satelite to Aircraft \item Aircraft's response back to satelite \item Time it takes for the aircrafts SDU(onboard computer) to respond called the SDU bias \item Responce recieved at the ground station \item The delay between the time the signal arrives at the ground station and the time it is processed to be sent back \end{itemize} \end{minipage} \hspace{.05\textwidth} \begin{minipage}{.4\textwidth} \centering \includegraphics[width=\textwidth]{BTOFig1.pdf} \captionof{figure}{BTO illustration} \end{minipage}
An equation can therefore be constructed using an average distance where (Distance = Speed \times Time): [Range(SATToAircraft) = \frac{c.(BTO-Bias)}{2} - Range(SatToGES)] (Bias) is the SDU bias and is constant for the flight and so can be calculated using the first half an hour of flight before takeoff. Where the aircraft’s location is fixed. (c) is the speed of light. [Bias = BTO-\frac{2[Range(SatToAircraft)-Range(SatToGES)]}{c}] We calculated a mean bias of -0.4950348991s, the bias ATSB uses (given in the report is -0.495679s. See appendix figure
We are provided with a table of times and BTO values. See appendix figure . We can use these values to generate a list of (Range(SatToAircraft)) values and times. To solve this we need a table of times and satelite positions see computational details. Once we have these we can then work out the distance between the satelite and the GES which is in a constant position giving (Range(SatToGES)). [Range(SatToGES) = \sqrt{(x_{Sat}-x_{GES})^2+(y_{Sat}-y_{GES})^2+(z_{Sat}-z_{GES})^2}]
Then finally use the first equation and both these tables to generate a table of range values, the dist column, one for each of the seven handshakes:
| Date | DateSat | x | vx | Dist |
|---|---|---|---|---|
| 2014-03-07 18:25:27.421 | 2014-03-07 18:25:27.400 | 18136.79 | 0.0018860 | 36905.35 |
| 2014-03-07 19:41:02.906 | 2014-03-07 19:41:02.900 | 18145.32 | 0.0019099 | 36745.42 |
| 2014-03-07 20:41:04.904 | 2014-03-07 20:41:04.900 | 18152.42 | 0.0020370 | 36785.74 |
| 2014-03-07 21:41:26.905 | 2014-03-07 21:41:26.900 | 18160.03 | 0.0021580 | 36954.46 |
| 2014-03-07 22:41:21.906 | 2014-03-07 22:41:21.900 | 18167.82 | 0.0021375 | 37238.41 |
| 2014-03-08 00:10:59.928 | 2014-03-08 00:10:59.900 | 18178.16 | 0.0015841 | 37803.64 |
| 2014-03-08 00:19:29.416 | 2014-03-08 00:19:29.400 | 18178.94 | 0.0014917 | 37861.91 |
Seven handshake data, some columns excluded to fit
Appendix figure shows an example from ATSB of how this should look for the first half an hour of flight.
Taking a row of the table giving you a time, position of the satelite and the range you can draw a great circle on the earth:
\begin{figure}[h] \centering \includegraphics{range.png} \caption{RangeSatToAircraft and great circle} \end{figure}
Repeating this for the seven handhshakes gives you seven arcs:
\begin{minipage}{.5\textwidth} \centering \includegraphics[width=\textwidth]{arcs2.png} \captionof{figure}{Our Arcs} \end{minipage} \begin{minipage}{.5\textwidth} \centering \includegraphics[width=\textwidth]{arcs.png} \captionof{figure}{The seven arcs from ATSB} \end{minipage}
An analysis of the burst frequency offset (BFO) values provided by inmarsat (see appendix fig’ ) can determine where along the BTO arcs the aircraft was located. The burst frequency offset is defined as the difference between the expected and received frequency of transmissions caused by doppler shifts.
\begin{figure}[h] \includegraphics{BTOFig.png} \caption{BTO illustration} \end{figure}
- (\delta f_{AFC}+\delta f_{sat}) are provided by ATSB see appendix figure
- (\delta f_{bias}) is provided as 152.5(H_z) see appendix figure
- This leaves (\delta f_{down}), (\delta f_{up}) and (\delta f_{comp}) to be calculated
Using a basic doppler shift formula with a stationary observer (GES) and a source moving towards the observer. This direction is arbitary and affects the sign on the bottom of the equation. [\Delta F_{down} = f_{down} (\frac{c}{c-v_s} -1)]
- where (v_s) is the velocity of the satelite towards the GES
- where c is the speed of light
- (f_{down}) is a constant provided by ATSB and is the frequency before shift of the downlink signal (f_{down} = 3615.1525MH_z)
We have the velocity of the satelite as an xyz vector earth fixed geomertry. To turn this into velocity towards GES we use the vector projection in the direction of GES [\textbf{v}_s = \frac{\textbf{v}\cdot \textbf{s}}{|s|}]
\begin{minipage}{0.7\textwidth}
We need three vectors:
\begin{itemize}
\item
Using a basic doppler shift formula with a moving observer (MH370) and source. Both moving towards each other. [\Delta F_{up} = f_{up} (\frac{c+v_{s}}{c-v_{pl}} -1)]
- where (v_s) is the velocity of the satelite towards the plane
- where c is the speed of light
- (f_{up}) is a constant provided by ATSB and is the frequency before shift of the uplink signal (f_{up} = 1646.6525MH_z)
Again we have the velocity of the satelite as an xyz vector earth fixed geomertry. To turn this into velocity towards the plane we use the vector projection in the direction of the plane. [\textbf{v}_s = \frac{\textbf{v}\cdot \textbf{s}}{|s|}]
\begin{minipage}{0.7\textwidth}
We need three vectors:
\begin{itemize}
\item
(\delta f_{comp}) is defined as the frequency compensation applied by the aircraft, to attempt to compensate for the doppler shifts. This assumes that the satelite is in a fixed position above the equater at its nominal position. However due to the satelite drift at the time the delta f comp could not fully compensate for the doppler shift which is why we see a (\delta f{up}) value.
The nominal position is stated in the report as a longitude of 64.5(^{\circ}). Above the equater therefore a latitude of 0(^{\circ}). There is no nominal value for the altitude given so we would have to assume a value for this. One method could be to assume an average value of the altitude over time.
It is also not stated in the report how this calculation is done by the aircraft’s onboard computer. However you could assume it uses a standard doppler shift formula assuming a stationary observer (satelite):
[\delta f_{comp} = f_{up} (\frac{c}{c-v_{pl}})]
[BFO = \Delta F_{up} + \Delta F_{down} + \delta f_{comp} + (\delta f_{AFC} + + \delta f_{sat}) + \delta f_{bias}]
[BFO = f_{up} (\frac{c+v_{s}}{c-v_{pl}} -1) + f_{down} (\frac{c}{c-v_s} -1) + f_{up} (\frac{c}{c-v_{pl}}) + const ] where (const = \delta f_{AFC}+\delta f_{sat} + \delta f_{bias}) ; (v_s = |\textbf{v}_s|) and (\textbf{v}_s = \frac{\textbf{v}\cdot \textbf{s}}{|s|})
As you can see you have two unknowns the velocity of the plane and its position. So the only way to solve this would be to use a monte carlo or numerical method. Finding the most probable positions and velocities using a probabilistic analaysis along each arc for each arc.
We know that the plane must cross the first arc at 18:25, we also know that it’s last known position from our initial path is the last radar contact at 18:22.
\begin{minipage}{0.75\textwidth} An iterative process is used to determine the path from the last radar point and the arc. This is described in more detail after this. However with our current 1st arc position the plane can not make to the arc in time. Even if it flies at the maximum theoretical speed. We discovered however that by changing our bias to the bias given in the ATSB report the arcs shift to the right towards the radar point. We also had to increase the speed for it to reach to 320$ms^{-1}$ WHY THIS SPEED. You can see the result to the right. You can also see below that the new arcs are closer to the ones provided by ATSB.
\end{minipage} \begin{minipage}{0.2\textwidth} \includegraphics{SprintPath.png} \end{minipage}
\begin{minipage}{.5\textwidth} \centering \includegraphics[width=\textwidth]{arcs1.png} \captionof{figure}{Our new arcs} \end{minipage} \begin{minipage}{.5\textwidth} \centering \includegraphics[width=\textwidth]{arcs.png} \captionof{figure}{The seven arcs from ATSB} \end{minipage}
Now we needed to find a path between each arc. Starting with the point at 18:25. With an incomplete BFO analysis you have to make some reasonable assumptions about the flight path:
- Constant speed of 450 knots
- Constant altitude of 35,000 feet
- The plane always travels in straight lines between each arc
\begin{minipage}{0.45\textwidth}
Once you have a starting point on the arc each path is found through an iterative process for each row/arc in the table figure \ref{data}:
\begin{itemize}
\item First draw a circle around your origin point with
This gives you two possible routes the plane could have taken, one taking a northern trajectory and another taking a southern trajectory:
\begin{figure}[h] \centering \begin{minipage}{0.3\textwidth} \includegraphics[width=0.93\textwidth]{north1.png} \end{minipage} \begin{minipage}{0.3\textwidth} \includegraphics{north2.png} \end{minipage} \hspace{0.2cm} \begin{minipage}{0.3\textwidth} \includegraphics[width=0.8\textwidth]{north3.png} \end{minipage} \caption{Google earth projection of the northern trajectory} \end{figure}
\begin{minipage}{0.3\textwidth} Here is the measured BFO values plotted on a graph against time from the ATSB report.\bigskip
As you can see the BFO values are much more consistent with the predicted BFO values for a southern trajectory.\bigskip
Which means we can exclude our nothern trajectory as a possible route. \end{minipage} \hspace{0.05\textwidth} \begin{minipage}{0.65\textwidth} \includegraphics{traj.png} \captionof{figure}{BFO projection for nothern and southern routes} \end{minipage}
Now we know the plane must take a southern trajectory the last point of this on the seventh arc marks the last known position of the plane.
As the plane crosses the seventh arc at 19:29 the handshake is an unscheduled log on request from the plane. This could mean a loss of fuel at this point as the emergency power systems would have rebooted and tried to contact the satelite network. It takes ~ 2 minutes for the SDU and ADU onboard computers to reboot after a power failure so fuel loss is expected to be about 2 mins before the failed handshake, so about 19:27. This time is also consistent with the flights fuel capabilities knowing its amount of fuel from the last acars at 17:06 and the time of flight REFERENCE.
So you can take the bearing between the last path and the 7th arc position. Then go back two minutes in time giving you a distance assuming a constant speed. This gives you a point slightly north east of the 7th arc position. As the point of fuel loss (0:17).
\begin{figure}[h] \centering \includegraphics[width=.7\textwidth]{lastPoint.png} \caption{Google earth screenshot of 6th and 7th arcs; fuel loss point; seventh arc position and the most probable location from inmarsat} \end{figure}
The plane can only go so far from here. The circle shows the maximum distance before hitting the ocean. This is calculated by an efficient glide ratio for a 777 of 17:1. Meaning the plane can glide horizontally about 17 times its altitude. i.e. (radius = glide dist = 17 \times 35,000feet = 181 km). The assumption that the plane glides is also consistent with some of the wreckage found showing large intact pieces left REFERENCE.
Knowing the plane keeps a consistent bearing from the 6th arc, throught the fuel loss point to the 7th arc. It is a resonable assumption that it stays true to this after the 7th arc. Following the yellow radial line. Gliding to near the maximum distance at this bearing you can give a final point for the crash site, where the yellow line intersects the circle.
\begin{figure}[h] \centering \includegraphics[width=.7\textwidth]{lastPath.png} \caption{Last path estimate, and crash site} \end{figure}
For our BTO analysis we needed accurate satelite data for the position of the satelite over time. Unfortunatley little information is given online or in the report about the satlite position.
We decided to use a simulation of the satelite. To predict its drift over time given the initial conditions. We used intitial conditions given in the ATSB report. See appendix figure . For time 16:30:00 we have a position in earth fixed coordinates xyz and velocity x’y’z’.
We used NASA’s open source general mission analysis tool (GMAT) to model the satelite’s trajectory. This gives us satelite data accurate to the 1/10 of a second. Which is important as the satelite drifts substantially throughout the flight.
\begin{figure}[h] \includegraphics{sat1.png} \caption{Screenshot of GMAT program inputting intial conditions} \end{figure}
\begin{figure}[h] \begin{minipage}{.5\textwidth} \includegraphics{satmap.png} \end{minipage} \begin{minipage}{.5\textwidth} \includegraphics{satdrift.png} \end{minipage} \caption{Screenshot of GMAT showing ground track plot and satelite drift} \end{figure}
We then set the program to give us a report file containing all the neccessary information:
\begin{figure}[h] \includegraphics{satdata.png} \caption{GMAT Report file preview} \end{figure}
The goal of this project is to take the input data and convert it into a final path for the plane. Not only that but I wanted the code to run all in one automatic script so changes could be made to the satelite data or inmarsat data and the code would be able to run again from scratch. I also wanted a nice way of visualising this so I used google earth’s kml library.
Python seemed like an appropriate choice for programming language it also had all of the libraries I would need. Such as the pandas library whcih is used for parsing all of the data given by inmarsat see appendix figure and the gmat report file into a useable table for calculations. It was a major challenge to parse them into two usable tables. Then I had to match the time given in the inmarsat data to a relevant time in the satelite report file. All of this is done in the getData function see appendix
Once we have this condensed into one table, you end up with a table with about 500 rows. The bias is then calculated for the first half an hour see . However we ended up using ATSB’s bias value so this function is now void. The data is then further condensed into a table of seven arcs giving us figure . See appendix .
I made various functions for plotting lines, points and circles in google earth. All of which is saved in a kml file which can be opened in google earth to show a visual representation of the data. I also used the simplekml library. See appendix
The next task is drawing the arcs, intitial and final paths. See appendix to . An attempt is made at the BFO analysis giving us deltaFComp and deltaFDown in appendix . Finally the glide ratio is calculated and a final path estimated saving to the kml file. See .
| Arc | Date | BTO | BFO | bias | Dist | deltaSatAFC | deltaFBias | deltaFDown |
|---|---|---|---|---|---|---|---|---|
| 1 | 2014-03-07 18:25:27.421 | 12520 | 142 | -0.495679 | 36905.35 | 10.8 | 152.5 | -1737.185086 |
| 2 | 2014-03-07 19:41:02.906 | 11500 | 111 | -0.495679 | 36745.42 | -1.2 | 152.5 | -5.711436 |
| 3 | 2014-03-07 20:41:04.904 | 11740 | 141 | -0.495679 | 36785.74 | -1.3 | 152.5 | 1361.827263 |
| 4 | 2014-03-07 21:41:26.905 | 12780 | 168 | -0.495679 | 36954.46 | -17.9 | 152.5 | 2623.988131 |
| 5 | 2014-03-07 22:41:21.906 | 14540 | 204 | -0.495679 | 37238.41 | -28.5 | 152.5 | 3680.905844 |
| 6 | 2014-03-08 00:10:59.928 | 18040 | 252 | -0.495679 | 37803.64 | -37.7 | 152.5 | 4760.278758 |
| 7 | 2014-03-08 00:19:29.416 | 18400 | 182 | -0.495679 | 37861.91 | -38.0 | 152.5 | 4826.809098 |
Summary table of results
Here is a summary of the output of the python code represented as a table. With a few columns excluded for the results section. You can find the full data outputted from the code in appendix .
- Compare your results with those expected/predicted by theory.
- Provide reasoned explanation for your results.
- Compare your results with known results from the literature, if appropriate.
- Give suggestions for further work, where appropriate
Conclude with a brief sum mary of main findings, and their potential significance•
- Use a consistent style – either alphabetic or numeric – to list the references cited.
- In the case of numeric, references should be numbered in the order in which they appear in the text.
\begin{landscape} \appendix \counterwithin{figure}{section} \counterwithin{table}{section}
\section{Appendix tables and figures}
\rowcolors{2}{gray!6}{white} \begin{table}[!h]
\caption{\label{tab:unnamed-chunk-3}\label{FinalData}Full final data} \centering \begin{tabular}[t]{rllrrrrrrr} \hiderowcolors \toprule Arc & Date & DateSat & x & y & z & vx & vy & vz & Lat\ \midrule \showrowcolors 1 & 2014-03-07 18:25:27.421 & 2014-03-07 18:25:27.400 & 18136.79 & 38071.78 & 1149.2508 & 0.0018860 & -0.0011539 & 0.0267314 & 1.5626235\ 2 & 2014-03-07 19:41:02.906 & 2014-03-07 19:41:02.900 & 18145.32 & 38067.08 & 1206.1094 & 0.0019099 & -0.0009101 & -0.0018866 & 1.6399145\ 3 & 2014-03-07 20:41:04.904 & 2014-03-07 20:41:04.900 & 18152.42 & 38064.10 & 1158.0904 & 0.0020370 & -0.0007658 & -0.0246225 & 1.5746445\ 4 & 2014-03-07 21:41:26.905 & 2014-03-07 21:41:26.900 & 18160.03 & 38061.35 & 1029.8396 & 0.0021580 & -0.0007836 & -0.0457840 & 1.4003103\ 5 & 2014-03-07 22:41:21.906 & 2014-03-07 22:41:21.900 & 18167.82 & 38058.20 & 831.9831 & 0.0021375 & -0.0009996 & -0.0636594 & 1.1313423\ \addlinespace 6 & 2014-03-08 00:10:59.928 & 2014-03-08 00:10:59.900 & 18178.16 & 38051.35 & 435.2215 & 0.0015841 & -0.0015748 & -0.0819975 & 0.5919005\ 7 & 2014-03-08 00:19:29.416 & 2014-03-08 00:19:29.400 & 18178.94 & 38050.54 & 393.1532 & 0.0014917 & -0.0016330 & -0.0831191 & 0.5346963\ \bottomrule \end{tabular} \end{table} \rowcolors{2}{white}{white}
\begin{table}[!h] \centering\rowcolors{2}{gray!6}{white}
\begin{tabular}{rrrlrrrrrrr} \hiderowcolors \toprule Lat & Lon & Alt & ChType & BTO & BFO & bias & Dist & deltaSatAFC & deltaFBias & deltaFDown\ \midrule \showrowcolors 1.5626235 & 64.52761 & 35808.66 & R-Channel RX & 12520 & 142 & -0.495679 & 36905.35 & 10.8 & 152.5 & -1737.185086\ 1.6399145 & 64.51440 & 35809.68 & R-Channel RX & 11500 & 111 & -0.495679 & 36745.42 & -1.2 & 152.5 & -5.711436\ 1.5746445 & 64.50396 & 35808.69 & R-Channel RX & 11740 & 141 & -0.495679 & 36785.74 & -1.3 & 152.5 & 1361.827263\ 1.4003103 & 64.49301 & 35806.16 & R-Channel RX & 12780 & 168 & -0.495679 & 36954.46 & -17.9 & 152.5 & 2623.988131\ 1.1313423 & 64.48162 & 35802.30 & R-Channel RX & 14540 & 204 & -0.495679 & 37238.41 & -28.5 & 152.5 & 3680.905844\ \addlinespace 0.5919005 & 64.46494 & 35794.61 & R-Channel RX & 18040 & 252 & -0.495679 & 37803.64 & -37.7 & 152.5 & 4760.278758\ 0.5346963 & 64.46350 & 35793.80 & R-Channel RX & 18400 & 182 & -0.495679 & 37861.91 & -38.0 & 152.5 & 4826.809098\ \bottomrule \end{tabular} \rowcolors{2}{white}{white} \end{table} \end{landscape}
\begin{figure} \includegraphics{table1} \caption{Table from definition of underwater search areas showing example BTO calculation} \label{table1} \end{figure} \begin{figure} \includegraphics{exampleLog.pdf} \caption{Log file given provided by inmarsat} \label{exampleLog} \end{figure} \begin{figure} \includegraphics{biasTable.png} \caption{BTO calibration table given provided by inmarsat} \label{biasTable} \end{figure}
\begin{figure}[h] \centering \includegraphics[width=0.5\textwidth]{DeltaAFC.png} \caption{$\delta f_{sat} + \delta f_{AFC}$ values from ATSB} \label{DeltaAFC} \end{figure}
\begin{figure}[h] \centering \includegraphics[width=0.5\textwidth]{Heading.png} \caption{BFO example for 17:07 from ATSB} \label{Heading} \end{figure}
\clearpage
import numpy as np
import simplekml
from polycircles import polycircles as pc
import math
import time
import pandas as pd
pd.set_option("display.max_rows",999)
pd.set_option('display.width', 1000)
from datetime import datetime, timedelta
import geopy
from geopy.distance import VincentyDistance
from scipy.spatial import distance
from sympy.solvers import solve
from sympy import Symbol
#Constants
posGES = np.array([-2368.8, 4881.1, -3342.0])
posAES = np.array([-1293.0, 6238.3, 303.5])
c = 299792458/1000#km/s
iterationConstant = 8000
alt = 10668*1e-3#function to parse data from satelite report file and inmarsat csv file
def getData(Time = 3):
x,y,z,vx,vy,vz,lat,lon,dateSat,alt = ([] for i in range(10))
#Grab InmarSat Data
data = pd.read_csv("inmarsat.csv", usecols=[0,8,25,27])
data.rename(columns={'Time':'Date', 'Frequency Offset (Hz)': 'BFO', 'Burst Timing Offset (microseconds)': 'BTO', 'Channel Type': 'ChType'}, inplace=True)
data['Date'] = pd.to_datetime(data['Date'], format='%d/%m/%Y %H:%M:%S.%f')
#Grab report data
Report = open("Report.txt", "r")
lines = Report.readlines()
#Grab report data
for i, line in enumerate(lines):
#if i <=1:
if "Nov" in line:
print(line)
lines.pop(i)
if i!=0:
dateSat.append(datetime.strptime(line.split(" ")[0], "%d %b %Y %H:%M:%S.%f"))
x.append(line.split()[4])
y.append(line.split()[5])
z.append(line.split()[6])
vx.append(line.split()[7])
vy.append(line.split()[8])
vz.append(line.split()[9])
lat.append(line.split()[10])
lon.append(line.split()[11])
alt.append(line.split()[12])
dateSatd = []
xd = []
yd = []
zd = []
vxd = []
vyd = []
vzd = []
lond = []
latd = []
altd = []
data = data[pd.notnull(data['BTO'])]
data = data.reset_index(drop=True)
data = data[pd.notnull(data['BTO'])]
data = data.reset_index(drop=True)
for i in range(len(data)):
for j in range(len(dateSat)):
if abs(dateSat[j]-data['Date'][i])<=timedelta(0,0,0,50):
dateSatd.append(dateSat[j])
xd.append(x[j])
yd.append(y[j])
zd.append(z[j])
vxd.append(vx[j])
vyd.append(vy[j])
vzd.append(vz[j])
latd.append(lat[j])
lond.append(lon[j])
altd.append(alt[j])
del dateSat[:j]
del x[:j]
del y[:j]
del z[:j]
del vx[:j]
del vy[:j]
del vz[:j]
del lat[:j]
del lon[:j]
del alt[:j]
break
data["DateSat"] = pd.Series(dateSatd)
data["x"] = pd.Series(xd)
data["y"] = pd.Series(yd)
data["z"] = pd.Series(zd)
data["vx"] = pd.Series(vxd)
data["vy"] = pd.Series(vyd)
data["vz"] = pd.Series(vzd)
data["Lat"] = pd.Series(latd)
data["Lon"] = pd.Series(lond)
data["Alt"] = pd.Series(altd)
data = data[['Date', 'DateSat', 'x', 'y', 'z', 'vx', 'vy', 'vz', 'Lat', 'Lon', 'Alt', 'ChType', 'BTO', 'BFO']]#rearrange columns
data.x = data.x.astype(float)
data.y = data.y.astype(float)
data.z = data.z.astype(float)
data.vx = data.vx.astype(float)
data.vy = data.vy.astype(float)
data.vz = data.vz.astype(float)
data.Lon = data.Lon.astype(float)
data.Lat = data.Lat.astype(float)
data.Alt = data.Alt.astype(float)
data.BTO = data.BTO.astype(float)
data.BFO = data.BFO.astype(float)
return data#recursive asks for use input
def inputR(inputText, wantedTextList):
inp = False
while inp == False:
string = input(inputText)
if string in wantedTextList:inp = True
return string
# returns bias given data
def getBias(posSat):
distSatGES = np.linalg.norm(posSat-posGES, axis = 1)
distSatAES = np.linalg.norm(posSat-posAES, axis = 1)
biasR = []
biasT = []
for i in range(len(data)):
if data['ChType'][i]=="R-Channel RX":
biasR.append((data['BTO'][i]*1e-6) - 2*(distSatAES[i]+distSatGES[i])/c )
if data['ChType'][i]=="T-Channel RX":
biasT.append((data['BTO'][i]*1e-6) - 2*(distSatAES[i]+distSatGES[i])/c )
bias = []
biasRn = 0
biasTn = 0
for i in range(len(data)):
if data["Date"][i]==datetime(2014,3,7,16,41,52,907000):#TakeOff
meanBiasR = np.mean(biasR)
meanBiasT = np.mean(biasT)
meanBiasT = -0.495679
meanBiasR=meanBiasT
print("The bias used is: ", meanBiasT, "s")
if data["Date"][i]<=datetime(2014,3,7,16,29,52,406000):#preTakeOff
if data['ChType'][i]=="R-Channel RX":
bias.append(biasR[biasRn])
biasRn = biasRn+1
elif data['ChType'][i]=="T-Channel RX":
bias.append(biasT[biasTn])
biasTn = biasTn+1
else:#postTakeOff
if data['ChType'][i]=="R-Channel RX": bias.append(meanBiasR)
elif data['ChType'][i]=="T-Channel RX": bias.append(meanBiasT)
bias = pd.Series(bias)
return bias, distSatGES
#gives indexes for data matching the arc dates
def getArcDates():
arcDate = []
arcIndexes = []
arcDate.append(datetime(2014,3,7,18,25,27))
arcDate.append(datetime(2014,3,7,19,41,00))
arcDate.append(datetime(2014,3,7,20,41,00))
arcDate.append(datetime(2014,3,7,21,41,24))
arcDate.append(datetime(2014,3,7,22,41,19))
arcDate.append(datetime(2014,3,8,0,10,58))
arcDate.append(datetime(2014,3,8,0,19,29))
for i in range(len(arcDate)):
for j in range(len(data)):
if abs(data["Date"][j]-arcDate[i])<=timedelta(0,5):
arcIndexes.append(j)
return arcIndexes
#converts latitude and longitude to earth centered earth fixed coordinates
def lla_to_ecef(lat, lon, alt):
import pyproj
ecef = pyproj.Proj(proj='geocent', ellps='WGS84', datum='WGS84')
lla = pyproj.Proj(proj='latlong', ellps='WGS84', datum='WGS84')
x, y, z = pyproj.transform(lla, ecef, lon, lat, alt, radians=False)
return x, y, z
#converts ecef to lat lon coords
def ecef_to_lla(x, y, z):
import pyproj
ecef = pyproj.Proj(proj='geocent', ellps='WGS84', datum='WGS84')
lla = pyproj.Proj(proj='latlong', ellps='WGS84', datum='WGS84')
lon, lat, alt = pyproj.transform(ecef, lla, x, y, z, radians=False)
return lat, lon, alt#Main code start
pd.options.mode.chained_assignment = None
print("getting data...")## getting data...
data = getData()
print("done")## done
arcDates = getArcDates()
data["BTO"][arcDates[0]] = data.iloc[arcDates[0]].loc["BTO"]-4600
data["BTO"][arcDates[6]] = data.iloc[arcDates[6]].loc["BTO"]-4600
data.to_csv("Data.csv")
data = pd.read_csv("Data.csv")
data = data.drop(['Unnamed: 0'], axis=1)
data['Date'] = pd.to_datetime(data['Date'], format='%Y-%m-%d %H:%M:%S.%f')
data['DateSat'] = pd.to_datetime(data['DateSat'], format='%Y-%m-%d %H:%M:%S.%f')
arcDates = getArcDates()
#Some more data assignment
data["bias"], distSatGES = getBias(data.as_matrix(['x','y','z']))## The bias used is: -0.495679 s
data["Dist"] = (0.5*c*((data["BTO"].values*1e-6)-data["bias"].values)) - distSatGES
deltaSatAFC = np.zeros(len(data))
deltaFBias = np.full(len(data), 152.5)
data["deltaSatAFC"] = pd.Series(np.asarray(deltaSatAFC))
data["deltaFBias"] = pd.Series(np.asarray(deltaFBias))
data.deltaSatAFC = data.deltaSatAFC.astype(float)
data.deltaFBias = data.deltaFBias.astype(float)
data["deltaSatAFC"][arcDates[0]] = 10.8
data["deltaSatAFC"][arcDates[1]] = -1.2
data["deltaSatAFC"][arcDates[2]] = -1.3
data["deltaSatAFC"][arcDates[3]] = -17.9
data["deltaSatAFC"][arcDates[4]] = -28.5
data["deltaSatAFC"][arcDates[5]] = -37.7
data["deltaSatAFC"][arcDates[6]] = -38.0
data = data[data.deltaSatAFC != 0]
data = data.reset_index(drop=True)def drawPoint(Name, Lat, Lon, Alt):
pnt = kml.newpoint(name= Name)
pnt.coords = [(Lon, Lat, Alt)]
pnt.altitudemode = 'relativeToGround'
return 1
def drawCircle(Name, Lat, Lon, Radius, color):
circle = pc.Polycircle(latitude=Lat, longitude=Lon, radius=Radius, number_of_vertices=iterationConstant)
pol = kml.newpolygon(name=Name, outerboundaryis=circle.to_kml())
pol.style.polystyle.color ="000000ff" # Transparent
pol.style.linestyle.color = color
pol.altitudemode = 'absoluteAltitude'
pol.tessellate = 1
return circle
def drawLine(Name, originLat, originLon, destLat, destLon, color):
ls = kml.newlinestring(name = Name)
ls.style.linestyle.color = color
ls.coords = [(originLon, originLat), (destLon, destLat)]
return 1kml = simplekml.Kml()
drawPoint("Satposition", np.mean(data["Lat"].values), np.mean(data["Lon"].values),357860)
arcIndexes = arcDates
arcNo = 0
circles = []
#draw arcs
for i in range(len(data)):
arcNo = arcNo+1
a = data["Dist"][i]
b = np.square(data["x"][i])+np.square(data["y"][i])+np.square(data["z"][i])
b = np.sqrt(b)
c = 6371+alt#+73
#c = 6371+alt+50
pheta = np.square(b)+np.square(c)-np.square(a)
pheta = pheta / (2*b*c)
pheta = np.arccos(pheta)
radius = c*pheta
datetime(2014,3,7,16,29,52,406000)
radius = radius*1000
circles.append(drawCircle("Arc"+str(arcNo), data["Lat"][i], data["Lon"][i], radius, simplekml.Color.white))#find path between arcs given a direction north or south
def findShortest(name, radius, origin, alt, circle, direction):
distArr = []
circle = circle.to_lat_lon()
lastDist = 99999
for i in range(len(circle)):
destination = geopy.Point(circle[i][0], circle[i][1], alt)
distance = VincentyDistance(origin, destination).meters
dist = distance-radius
if (lastDist>0) and (dist<0) and (direction=="North"):
minDist = dist
j = i
if (lastDist<0) and (dist>0) and (direction=="South"):
minDist = dist
j = i
lastDist = dist
return geopy.Point(circle[j][0], circle[j][1], alt)
def drawPath(origin, dest, time, no):
if time.minute<10:
drawPoint(str(time.hour)+":0"+str(time.minute), dest.latitude, dest.longitude, alt)
else:
drawPoint(str(time.hour)+":"+str(time.minute), dest.latitude, dest.longitude, alt)
drawLine("Path"+str(no), origin.latitude, origin.longitude, dest.latitude, dest.longitude, simplekml.Color.red)
return 1
#get destination given origin times and breaing
def getDest(origin, lastTime, time, bearing, radius):
dest = VincentyDistance(kilometers=radius*1e-3).destination(origin, bearing)
return dest
alt = alt*1000
speed = 231.5#450knots
time = datetime(2014,3,7,17,6,43)
origin = geopy.Point(2.7, 101.7, 0)
dest = geopy.Point(5.27, 102.79, alt)
drawPath(origin, dest, time, 1)
origin = dest
lastTime = time
time = datetime(2014, 3, 7, 17, 21, 13)
deltaT = abs(lastTime-time).total_seconds()
radius = speed*deltaT
dest = getDest(origin, lastTime, time, 25, radius)
drawPath(origin, dest, time, 2)
origin = dest
lastTime = time
time = datetime(2014,3,7,17,52,27)
dest = geopy.Point(5.2, 100.2, alt)
drawPath(origin, dest, time, 3)
origin = dest
lastTime = time
time = datetime(2014,3,7,18,22,12)
dest = geopy.Point(6.65, 96.34, alt)
drawPath(origin, dest, time, 4)
speed = 320#Max speed
origin = dest
lastTime = time
time = data["Date"][0]
deltaT = abs(lastTime-time).total_seconds()
radius = speed*deltaT
destArr = []
dest = findShortest("test", radius, origin, alt, circles[0], "North")
destArr.append(dest)
firstArcPos = dest
drawPath(origin, dest, time, 5)speed = 231.5#450knots
#draw paths
for i in range(0,6):
origin = dest
deltaT = abs(data["Date"][i+1]-data["Date"][i]).total_seconds()
radius = speed*deltaT
time = data["Date"][i+1]
dest = findShortest("test", radius, origin, alt, circles[i+1], "South")
destArr.append(dest)
drawPath(origin, dest, time, 5+i)
#drawCircle('test', origin.latitude, origin.longitude, radius, simplekml.Color.green)
#draw green circle for example
origin = dest
lastTime = time
time = lastTime-timedelta(0,120)
deltaT = abs(lastTime-time).total_seconds()
radius = speed*deltaT
dest = getDest(origin, lastTime, time, 7.70, radius)
drawPath(origin, dest, time, 11)#give a table of delta F comps
def getFComp(posPl, speed, posSat):
v = v/1000
#sat = [0,64.5,35786*1e3]
#sat = lla_to_ecef(sat[0], sat[1], sat[2])
#sat = np.array(sat)*1e-3
s = posSat-posPl
vs = np.dot(v,s)
vs = vs/np.linalg.norm(s)
Fup = 1646.6525*1e6
deltaFComp = Fup*(((c+vs)/c)-1)
return deltaFComp
#BFO Analysis
deltaFDown = []
for i in range(len(data)):
v = np.array([data["vx"][i], data["vy"][i], data["vz"][i]], dtype=float)
s = np.array([data["x"][i], data["y"][i], data["z"][i]], dtype=float)
s = s-posGES
vS = np.dot(v, s)/np.linalg.norm(s)
FDown = 3615.1525e6
deltaFDown.append(FDown*((c/(c+vS))-1))
data["deltaFDown"] = pd.Series(deltaFDown)
data.deltaFDown = data.deltaFDown.astype(float)maxAlt = 10668#35kfeet
glideDist = maxAlt*16.995
drawCircle("Glide", dest.latitude, dest.longitude, glideDist, simplekml.Color.white)
drawPoint("Their location", -35.6, 92.8, 0)
print(data)
#save to kml file ready for importing to google earth## Date DateSat x y z vx vy vz Lat Lon Alt ChType BTO BFO bias Dist deltaSatAFC deltaFBias deltaFDown
## 0 2014-03-07 18:25:27.421 2014-03-07 18:25:27.400 18136.788690 38071.780267 1149.250781 0.001886 -0.001154 0.026731 1.562623 64.527615 35808.658697 R-Channel RX 12520.0 142.0 -0.495679 36905.345735 10.8 152.5 -1737.185086
## 1 2014-03-07 19:41:02.906 2014-03-07 19:41:02.900 18145.322644 38067.080600 1206.109395 0.001910 -0.000910 -0.001887 1.639914 64.514401 35809.676311 R-Channel RX 11500.0 111.0 -0.495679 36745.423272 -1.2 152.5 -5.711437
## 2 2014-03-07 20:41:04.904 2014-03-07 20:41:04.900 18152.415261 38064.097851 1158.090407 0.002037 -0.000766 -0.024623 1.574644 64.503959 35808.689335 R-Channel RX 11740.0 141.0 -0.495679 36785.744457 -1.3 152.5 1361.827263
## 3 2014-03-07 21:41:26.905 2014-03-07 21:41:26.900 18160.033945 38061.351242 1029.839567 0.002158 -0.000784 -0.045784 1.400310 64.493009 35806.160960 R-Channel RX 12780.0 168.0 -0.495679 36954.463239 -17.9 152.5 2623.988131
## 4 2014-03-07 22:41:21.906 2014-03-07 22:41:21.900 18167.817569 38058.202812 831.983119 0.002137 -0.001000 -0.063659 1.131342 64.481623 35802.301035 R-Channel RX 14540.0 204.0 -0.495679 37238.408842 -28.5 152.5 3680.905844
## 5 2014-03-08 00:10:59.928 2014-03-08 00:10:59.900 18178.157195 38051.354149 435.221535 0.001584 -0.001575 -0.081998 0.591901 64.464937 35794.610366 R-Channel RX 18040.0 252.0 -0.495679 37803.640202 -37.7 152.5 4760.278758
## 6 2014-03-08 00:19:29.416 2014-03-08 00:19:29.400 18178.941079 38050.536935 393.153216 0.001492 -0.001633 -0.083119 0.534696 64.463497 35793.797327 R-Channel RX 18400.0 182.0 -0.495679 37861.914631 -38.0 152.5 4826.809098
kml.save("Flight.kml")
#save data
data.to_csv("FinalData.csv")