Locating MH370

The world has been struggling with the location of MH370 for months. Lately, it has become common to question even the rough location of the wreck“the model they created showing arcs and Doppler readings was rigorously tested, initially on other aircraft on the satellite at the same time, and then against previous flights by the same aircraft. With minor disagreements both the position and the Doppler reading of those aircraft was predicted accurately.” deduced by Inmarsat and other experts and organizations by ignorant people who assume because they don’t understand the methods that no one else does and the world has been wasting time and energy on “educated guesses” or error.

It’s pathetic that CNN and others give “conspiracy theorists”folks who have no clue time to spout their ignorance as truth as compared to hard facts, measurement, calculation and science. I know a little of all of these and will shed some light, I hope.

There are a multitude of sources of information available to analyze the Inmarsat data which was delivered today. Inmarsat knew the position of the satellite precisely. Inmarsat knew several given points on the early flight of the plane. Inmarsat knew the behaviour of that plane and others before and after the day in question confirming their calculations. Still, ignorant people demand the truth they can’t handle.

The reason Inmarsat and others haven’t shows the public the detailed calculations is that Malaysia didn’t agree to that. Heaven only knows why.

Here are some key bits of information from Page 3:
“7/03/2014 16:00:13.406 … Log-on/Log-off Acknowledge 103 14820”
That’s pre-takeoff data. The time is important and the last two numbers, the burst frequency offset, 103 Hz and the burst timing delay, 14.82 milliseconds. Takeoff was around 16:41 (page 20). The first logon after takeoff was at :“7/03/2014 18:25:27.421 … 142 17120”. See? The plane is much further away from the satellite (longer hand-shake) and travelling faster (higher frequency shift). That’s two pieces of physics that the doubters seem to lack. It takes light or other electromagnetic waves time to travel from A to B. The speed of radio waves is about 3X108 m/s, so the extra 2300 microseconds is a greater distance of 690000m, 690km from the satellite, not along the course of the plane, but in a straight line from the moving plane at some altitude to the satellite out over the Indian Ocean thousands of miles up. The frequency at which radio waves are received depends on the relative motion between the transmitter and the receiver, again, along the line between the two. That’s the Doppler shift, $latex f=(\frac{c+v_r}{c+v_t}) $ where $latex c $ is the speed of light, $latex v_r $ is the speed of the receiver and $latex v_t $ is the speed of the transmitter, all along the line between them. It’s a 3-D problem and it’s not X versus Y like a map. It’s frequency v time-delay. A talking head on CNN can’t get it and sure as Hell, most of their viewers can’t either. Leave it to the experts. They can work in hyperspace and relate the data to position to do the search.

Another things. These data are all measured. That means it has only these few digits of precision. Extend the maths out to thousands of miles and hours and the tiny errors in each measurement grow like a tree. The estimated position of the wreck is not only the result of the last data-point but a long sum of all the previous data. That’s why they haven’t found the plane instantly. All the calculations can do is give the general area. One can estimate the errors and how they grow to give an idea of the size of the area that has to be searched and it’s huge. That’s why it will take months and $millions. It’s not a piece for the 6 o’clock news. It’s a long hard campaign. One of the biggest errors involved in the calculation is that the speed and altitude of the plane are unknown past the land-based radars. All that has to be deduced from this rather poor substitute for GPS (Global Positioning System, which finds positions in a similar manner but from as many as 12 satellites simultaneously, averaging out errors and giving unique solutions down to within a few metres).

So, stop nagging on Inmarsat and Malysia Airlines and the searchers for not having found the plane promptly. It’s not their fault systems were turned off/disabled on the plane. It’s not their fault that the only information they have is convoluted. They know what they are doing and you don’t. They will find the plane sooner rather than later. Their knowledge is not nearly as precise as AF447 which took two years to find. The difference is that ACARS was not disabled and the plane was transmitting GPS coordinates until a minutes before the crash. Give these guys a break.

See MH370: Is Inmarsat right?.

About Robert Pogson

I am a retired teacher in Canada. I taught in the subject areas where I have worked for almost forty years: maths, physics, chemistry and computers. I love hunting, fishing, picking berries and mushrooms, too.
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3 Responses to Locating MH370

  1. dougman wrote, “I read that Canada is purchasing a few F35′s “.

    The IT of that plane may be absolutely wonderful but the airframe has had constant problems due to moving goalposts and some European fighter may prevail. There are problems like suitability for the North or landing on short runways (aircraft carriers, not that Canada has any, but these can’t even hitch a ride with Uncle Sam). It’s like a beta-aircraft, not a proven design.

  2. dougman says:

    Off-Topic: I read that Canada is purchasing a few F35’s and not surprisingly, the aircraft uses Linux for its systems.

    In the States, the FAA has achieved 30 percent more operational efficiency for 50 percent less cost, by using Linux in its software when it migrated back in 2006.

    Goes to show you that Win-Dohs is simply not an option, when lives are at stake.

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