Bose Einstein Condensate

The Genius Behind the Quantum Navigation Breakthrough
Dr Ben Miles

This thing is just nuts. Besides the subject matter, I don't think he actually names the genius behind this breakthrough. If he did, I missed it. I grew up hearing about inertial navigation and how these devices were big, complicated and expensive. Sometime between now and then, ring lasers came along, which was an improvement, but still comprehensible. Then came smartphones and MEMs and they just blew me away. I had been working in computers for a while, and all I had seen was bigger, faster machines doing gaudier and gaudier things. Then smartphone inertial navigation appeared and I was, let me just say this again, blown away.

Check out some these other posts on the subject.

St. Paul Alaska

T-Routes

The FAA (Federal Aviation Administration) is adding GPS guided flight paths in Alaska, whatever that means. I'm looking at the above map and I say 'wait a minute', what's with the paths that go out to the middle of the Bering Sea? Then I look at Google Maps and if you zoom in you will find the islands of St. Paul and St. George.


Southwest Alaska

Neither island is very big, but there are people living out there. They are both have airstrips. St. Paul also has fish processing plant.

Post about Cold Bay.

Post about Akutan.

Moscow Rules

Startup of a Russian "type 458" gyro block of a MiG-21 fighter after almost 40 years of storage
barjan82
YouTube Description:

The "type 458" gyro block (Russian: 458МКС-15-32) in combination with the AGD-1 1122A/B (Russian: АГД-1) type attitude indicator/artificial horizon is a part of the inertial navigation system used in the Mikoyan-Gurevich MiG-21 supersonic jet fighter aircraft. The same gyro block is also used on a big variety of other Russian aircraft still flying today. The shown gyro block was kept in storage for almost 40years after being rejected, this is the third startup after the storage. The current setup yet lacks the matching AGD-1 1122A/B type HSI instrument, instead the pitch indicator block (syncro resolver and AC servomotor with servo amp) of a AGB-3K type attitude indicator is wired up for operation. Power requirement of the system is 27V DC and 3x36V 400Hz AC. Steady state total power consumption of the system is around 60W off the 27V bus (with a solid state 3phase 400Hz sine-wave inverter with 80% efficiency). Video quality is rather poor as usual :)

Just the coolest thing I've seen today. The way it jerks into position and the way it takes forever to get to full speed are just very cool. Evidently they are still in use, though I think new designs all use MEMS and can fit inside your smartphone. Previous inertial navigation post here.

 

Sweet LORAN

Country Joe & The Fish "Not So Sweet Martha Lorraine"
The story about Eddie Rickenbacker ditching in the Pacific Ocean during WW2 got me to thinking: just how did those guys navigate back then? My dad was a gunner on a B-24 bomber during WW2 in the Pacific. Raids in the Pacific were very different than the ones in Europe. The ranges were much farther and navigation was much more critical. In Europe you head vaguely southeast from England for a hundred miles and you were over enemy territory. Drop your bombs and turn around, head northwest and in short order you will be over England which was littered with airfields. In the Pacific, if you screw up one number 3 places to the right of decimal point when plotting your return flight and you could easily miss your destination completely and end up like Eddie, floating around in the Pacific hoping someone comes looking for you.


History of the LORAN System
Excerpted from a 1947 Coast Guard film
They started with the same tools mariners had used for the last couple hundred years: a sextant, a compass and a chronometer. In Europe they soon got LORAN which was another one of those super-top secret projects, like the Norden bombsight, the proximity fuse, the atomic bomb and the code breakers at Bletchley Park. The original LORAN was only good for about 750 miles. It was superseded by LORAN-C and now by eLORAN. From the map shown at the end of the video, I surmise that they didn't get LORAN in the Pacific until very late in the war, and even then it didn't cover much of the area.


Lines plotted from difference in distance to points A and B.
LORAN is kind of weird. You need at least three base stations in order to get a good fix. The base stations all send out a periodic pulse, and they all do it simultaneously. You measure the difference in time between when you receive the pulse from two different stations, and that will place you on a line. Do that for a different pair of stations and you get a different line. Plot the two lines on a chart and their intersection is your location. Since radio waves travel at the speed of light, your timing needs to be critical. Light travels about one foot in one nanosecond (one billionth of second), so in a microsecond, it travels about one thousand feet. So if you can measure the arrival time of the pulses to the nearest microsecond, you can determine your location within a thousand feet, which for navigating across the ocean is fine.


MathLapse: Constructions by pin-and-string: conics | Construções de fio esticado: cónicas
Hyperbola starts at 1:45
LORAN is often called a "hyperbolic navigation system", but all that means is that the lines you plot on the charts are hyperbolas.

You can see about 200 miles from a B-24 flying at 25,000 feet.

P.S. Thinking about LORAN must have triggered my memory of Sweet Loraine. There is another version of the song sung by several people, but the one by Country Joe is the one I remember. I don't know where they got Martha from.

Zip-a-dee-do-dah

Mobile Mapping Indoors and Outdoors with Zebedee
It looks like they have combined several bits of technology:

• laser range finder
• inertial navigation using MEMS strain gauges
• GPS

plus a bit of the hand-waving robot from Lost In Space. Via The Guardian and Posthip Scott. For comparison, here is one of the first inertial navigation systems:

Litton Industries LN-3 Inertial Navigation System. Used in the F-104 Starfighter in the 1960's. It is roughly a thousand times bigger and a thousand times less accurate than a modern cell phone.

3G vs 4G

3G refers to third generation cellular telephone data transmission techniques, and 4G refers to, you guessed it, fourth generation. A new generation appears about every ten years or so. 4G started appeared a year or two ago. 4G is roughly ten times as fast as 3G. That's nice. Why do I care? I don't even have a cell phone. I don't really, but it might upset the aircraft instrumentation apple cart, at least for private airplanes. I realize that in the grand scheme of things, it is not really a very big apple cart, but it is a bit of a revolution, technology wise.  

BBFlight has an app for your tablet that can provide not just navigation aids in the form of maps, but also some basic aircraft instrumentation like compass, altimeter, artificial horizon, and airspeed indicator. I was a bit nonplussed when Marc told me about this today at lunch. How could it possible maintain an artificial horizon? I know smart phones have accelerometers that allow them to tell what angle they are at, but that isn't going to help in an airplane. When making a properly banked turn in an airplane, down is going to be down relative to the aircraft, not the earth. Artificial horizons use gyroscopes as a reference. Gyroscopes on gymbals maintain their orientation regardless of which way "down" appears to be.

Seems BBFlight's software is doing inertial navigation. It watches the accelerometer constantly, and can tell when you turn or bank or change speed either horizontally or vertically. It starts on the ground and keeps track of every move you make, and by keeping a running summation of these moves, it can tell where you are and what angle you are at. Commercial aircraft using similar technology can fly from New York to London and know their location to within six feet.

Tablets not only have cell phone connections, but they also have GPS, which can tell you where you are, so the program can compare the location it has determined inertially with what the GPS tells it.

We can determine speed using our old friend "rate times time equals distance". If you know where you were five minutes (or five seconds) ago, and you know where you are now, it is a simple matter to compute your velocity. Of course, this is land based velocity, not your airspeed, which could be substantially different. You probably will still want to have a real airspeed indicator.

GPS can also tell you your altitude. So you can do away with your altimeter, which is probably wrong anyway being as it is based on air pressure, which is always changing.

So what's this all got to do with 4G cellphone communications? This same program from BBFlight can also display maps on your tablet. As you fly along, the maps are updated on the fly, so to speak. If you are flying in a circle looking for a place to land, like an airport, a tablet that only has 3G communications can't keep up. You get a map, but you are turning, so it needs to update the map, and by the time it has the update, you have turned even more so what you are seeing is a very jerky video. With 4G the map rotation is perfectly smooth.

Rumor has it you can get cell phone coverage all the way from San Francisco to Portland (Oregon). I expect it's good anywhere along the I-5 corridor. 100 miles East it might be a different story.

As for the apple cart: this program will run on an iPad or any Android tablet. The aircraft instruments they replace cost thousands of dollars. It will be a while, probably a long while, before this tablet type instrumentation is accepted by the aviation community, and probably even longer before the FAA approves it, but it will happen.

Update November 2021 replaced missing image.