So.. in Apollo 13 is this the "gamble lock" they are talking about? (I might delete this by end of the video - 5:37 I think that was my clue but not a full answer lol)
Ex Naval Weapons Engineer here. A key feature of these gyro's when used as a compass is that they apply the coriolis effect to find north. The earth's rotation caused the gyro axis to move relative to the earths surface. This movement was inside a control system loop that applied precession to keep the gyro axis pointing to true north. If the earth was flat, gyro based navigation systems would not be able to find north. They would not work.
As a 1960 Fire Control Technician aboard the SS 311 Archerfish, I could never get an answer as to how the submarine’s gyro established true north. Thank you for answering the question, “coriolis effect.”
The gyros had a method of applying and adjustable torque to the gyro. The torque was adjusted for latitude. Zero torque at the equator. Max torque at the poles. The correct torque caused the gyro to precess to keep it horizontal to the earths surface and pointing north. This was the open loop adjustment. Fine errors were detected and minimised with the closed loop control system. At least that is what I remember from the 1990's @@MikeCasey311
@@MikeCasey311 On old gyro compasses, the Gyro Tech hangs weights on the gyro to precess the gyro at a rate that matches the earths rotation and keeps the gyro axis parallel with the earths surface. The weight depends on the latitude. Zero weight at the equator where the gyro axis of rotation matches the earths axis. This is open loop control. The closed loop control system is north seeking and does the fine adjustments.
On the Apollo program, just before a mid-course correction burn, the astronauts would use a telescope to orient the "stable member" (the platform that held the gyros and accelerometers) to an orientation fixed in space. They would then maneuver the orientation of the space craft (in pitch, roll and yaw) around that "stable member"...using it as a reference. The Apollo Guidance computer would tell the astronauts the exact pitch, roll and yaw to obtain in order to accurately orient the command module for what was called a "Delta V" engine burn. That "Delta V" maneuver was a short burn of the CM's main engine and/or the small thrusters on the side to make the necessary flight corrections to obtain the proper orbit around the moon.
Thank you for the response. Some say after the Apollo program we lost the technology to get to the moon. It's my knowledge that it was less about the technology and more about how the craft navigated there and back. Some of these shortcuts are just now being declassified like you just discussed.
Used to service Sperry rate gyros for F-4 Phantoms, three on each aircraft - roll, pitch and yaw. Simple things. Take them to bits, change bearings and balance the wheel and back together, gas fill and test. Magnetic field damping using a copper vane they had.
As an Electronics Engineer, in the early 80's I was delighted to be given a guided tour of a 747 aircraft. All these planes were equipped with Inertial guidance (INS) from the start. The INS was HUGE - and heavy. In recent years I have been routinely designing in tiny 9 axis (accelerometer, gyro, magnetometer) chips into products. MEMS devices have had an enormous effect on general life for most people who are technology connected, but very few appreciate just how mind-blowingly significant such devices have become. I am now retired but still vividly recall the 747 INS as a stark contrast to the near equivalent parts I need reading glasses to see nowadays. Great doco' Sir. Thank you.
Another intelligent, interesting and educational video. Thank you. Why a TV production company haven’t snapped you up is beyond me. Your presentations are leaps and bounds beyond what I’ve seen put out by the BBC, Sky etc….
When I was young in the Navy, worked on Sperry gyrocompasses (Mk 19 and Mk27). Two gyros inside, electrolytic levels, lots of servos and mechanical integrators. Fascinating bits of machinery that could find true north from just about anywhere as well as provided a stable roll/ pitch reference to feed into fire control systems.
An old friend of mine was a second then first officer then captain and later fleet manager of the BOAC B707, he told me that before the CAA would allow such a high tech device that frankly they didn’t understand aboard a British registered aircraft it would need thorough testing. A B707 was used and a discreet portion of the forward hold was used to house the device, for 6 months before every flight a white coated technician would crawl into the hold, open a locked door and perform what we now refer to as the alignment, the door was then locked again and at the end of the flight another white coated technician would crawl back in and take some readings, before the whole process was repeated again. The crew had no access to the output of the thing in the hold therefore it was still down to the second officer (nav) to use dead reckoning, star shoots, loran C and other basic navigation aids to provide a position known as a “cocked hat” where the aircraft was basically somewhere in the middle. That little box in the forward hold would eventually make the poor old second officer position obsolete but at that time he was the busiest guy on the flight deck.
@@CallMeByMyMatingName unfortunately he’s no longer with us, when I knew him he had not long stopped flying commercially, that was in 1986 by then he was in his early 60’s, by the time I lost touch with him in the mid 90’s he had had a couple of cancer scares and died a few years later. While everybody in aviation thinks they lived through the golden age (me included) I really think he did, he joined BOAC on the Lockheed Constellation then on to the Bristol Britannia, after a short period he joined the B707 fleet until they were retired. He was then offered a short term contract flying a small fleet of B727’s leased from Branif until he scored his dream type, the Concorde. He flew her for his last few years in BA as they had a retirement age of 55 in those days, but was able to pick up some contract work on the B727 until he had to finally hang up his wings.
I joined BOAC in 1971 and flew the B707 until 1978. I recall when dual inertial nav systems were retro fitted to the aircraft and it was the best thing since sliced bread! This meant there was no longer any requirement for a flight navigator on oceanic flights so the minimum crew became 3, ie Captain, First Officer and a Flight Engineer. But more importantly it brought the navigation on long overwater flights "in view" of the pilots whereas before the Flight Navigator would have been beavering away with charts on the flight nav table behind the pilots. All waypoints (maximum 9) had to be inserted manually into the inertial units as lat and longs so it was important to crosscheck tracks and distances to verify the correct positions had been loaded. As you flew along the route and passed waypoints you'd be loading the waypoints further along the route - good game! I can't recall whether it was west or eastbound but terminal errors were higher going in one direction due earth's rotation but final errors at end of an atlantic crossing would only be a few miles. You could also update position at the end of the crossing by accurately overflying a ground based radio beacon and when right overhead pressed an appropriate button and load the charted position of the radio beacon. At the end of the flight terminal errors were recorded for the airline nav dept and engineers to monitor performance. One revelation is that before inertial nav aircraft over the oceans were often 30 or 40 miles off track. When inertial came along you'd be halfway across the pond and actually see opposite direction traffic (at least 2,000 feet above or below) go right over or below you - something we rarely saw before! Also the extra accuracy meant that separation over the pond could be reduced which increased the flow rate on routes.
@@fireflyrobert it really was a time of rapid advances, I did my ATPL writens in 1986 and by then the CAA felt that they must add some questions about these new fangled INS thingies so I got about 5 questions mostly odd unpractical stuff in my instruments paper, unfortunately they were a little behind the times as by then the INS had been phased out in favour of the IRS system. My first Jet was the DC9, I joined the fleet in late 88 and left it in early 95, as it was basically a Cherokee with JT8D’s it had no long range nav kit at all, when I first flew the thing nobody really minded you being a few miles off course but by the end of my time on her ATC had got used to all the other aircraft going where they were told to so we would often be changed from making our own way to being given steers. I consider myself lucky that I’ve gone from the Do228 to the F27, then the DC9 followed by the B737, after that my long marriage with Airbus flying the A320 family and the A330 before landing the queen of the skies the B747-400, that would’ve been enough and to be honest after the Jumbo was rudely retired early I thought that that was it? But again luck has stepped in and I find myself doing my last few years on the A350. The changes along the way have truly been remarkable and not just the technology on the aircraft but the airspace changes also. I wonder what another 30 years will bring?
@@johnmorris7815 in many ways your career and experience echo mine. The advances we have seen in our careers have been quite remarkable. As you say what's coming in the next few decades?
I’d have to say that I’ve never disliked one of this channel’s videos. This video is new and already amongst the favorites I have! Extremely informative and entertaining! Keep up the great work, Paul!
Just stumbled across this channel. If you're interested: (Google) Autonetics / Anaheim ,Ca. At it's peak, the facility employed 36,000 people in Orange County - down the road from Disneyland. The facility was huge (Calisphere /images)
It was flown in a Boeing C-97 stratofreighter which shared the wings, engines and tail with the B-29. This system is covered in detail in the Apollo Guidance Computer episode of Moon Machines that was on the Science Channel
You are legitimately my favorite TH-cam creator. Your delivery is smooth and easy to digest. Always instant click when winding down after a busy day. Thank you for your time and education, SIR!
Back in the late 1940's these mech gyros and systems were found in surplus stores in LA such as Palleys; we got our hands on some of these devices, they were mesmorizing to us youngins.. In the early 1960's with a tech degree, worked for Autonetics on INS; Polaris N7F, A-4 (Skyhawk?), MM II, all in a one secured double-building. Semi conductors were already used heavily at this time, the INS integration was mind-blowing. Tektronix at this time was also integrating their front-end amplifiers with semi-conductors the first being the Tek 547 O'scope.
A former colleague worked for both Autonetics and Sperry on INS systems for aircraft and submarines. Had some interesting stories about slight initialization inaccuracies causing major drift in courses: one was caused by failure to compensate for the slight twisting of the carrier deck while sending starting point coordinates from the INU on the bridge to the unit on the aircraft. He was also involved with the electronic systems integration on the B-58 Hustler program. (I worked with him much later, outside of the defense sector.)
I had a friend who scavenged all the microwave surplus he could grab after the war. He knew what he was looking for, and found stuff in the surplus stores that nobody else would recognize, know how to wire up, or apply to anything... He was lighting gas tubes 8 feet away from his various microwave generators. The lights would dim in his house when he powered stuff up.
The prospect of the Gyro theory module was always the one more senior courses used to 'scare' us during my Artificer Apprenticeship training as a Weapons Engineer in the Royal Navy. This video is an order of magnitude more fascinating than the raw maths, I can confirm.
As an air-nav junkie, this is an early christmas present. The amount of innovative navigation techniques and systems from the 40s to the 80s before GPS was the standard is phenominal. Great choice of topic.
It makes sense and really underlines the importance of maintaining this type of knowledge, making sure it is not lost...perhaps developing it further. Who knows what may become possible in the future? I am struck by the intelligence of design found in these older ways and in the overall evolving of the ways we investigate the laws of physics to navigate. As a side note, I wonder if human powered flight will ever be possible, in some sort of way to fly like a true bird!
@@peteconrad2077im fairly certain submarines still use inertial navigation when underwater and then get a gps correction everytime they surface or pop a radio antenna up etc.
My Gandfarther worked for Sperry during WW2 in the UK (He had a protected occupation). He made the Gyroscopes that were used in ships and on planes for the war effort. Fascinating episode, we are all today standing on the shoulders of giants
For about a year around 1974 I worked for Ferranti in Edinburgh where they were developing the Inertial Navigation system for the Panavia Tornado. An amazing electrochemical bit of kit.
When I was doing a student apprenticeship with a uk defence electronics company in the early 1960’s we used solid state analogue electronics and miniature gyros (I had the same gimbles as a record player arm support) and it was tested by going round and round the Glasgow subway and achieved an amazing accuracy over a days travel in both directions.
I worked on the F111 and it was one of the earlier aircraft to use innertail navigation. Even in 1973, the inertial navigation assembly cost over 1 million dollars
Excellent coverage - I worked on analog and digital Inertial navigation systems(INS) in the U.S.A.F and remain absolutely amazed at how well they work. We depend too much on gps and should retain INS technology in newer applications.🧑🔧
I've heard that consideration is being given to updating and re-activating a number of LORAN stations in case GPS satellites are damaged or destroyed by EMP or radiation beams from space-based assets of rogue nations.
I follow several technology and history channels, I guess this is a combination of the two. Your videos are very relaxing and informative. It's always presented a and very easy to follow. Presented slowly and steadily with great visuals, it gives us time to really absorb and appreciate the presentations.
I used to work at MIT, where among other things I worked on components for small satellites. I spent at least ten days at Draper Lab in their vibration test facility, having assemblies tested on their sinusoidal sweep equipment so that what I'd made could go through an equivalent of the forces encountered during a rocket launch. Along with that, I had a friend whose father hard worked there, and at some point years ago I was given a memento from the dad's workdays - a gyroscope housing. I don't have much knowledge of where it was used but given its size (a bit smaller than a basketball) I'd guess it was for early (1960's) missile...
This type of system was on the sub that I served on for 4 years. I ran this system which ours was the upgrade to this system. It really worked well and we had a total of 3 redundant systems. SO if one broke the 3 others took over and you could also compare the 3 systems. It was really cool and this was back in the 1980s.
This is a good amount to take in. I know I appreciate having piezoelectric gyros on my 3D RC choppers. Without them, it would be nearly impossible to keep any sort of heading.
@@MadScientist267 Same thing. It uses internal inertia references to make course correction adjustments so that the primary changes come from the controller.
Mk-19 Gyrocompass Tech. First encounter with "Synthetic Lubrication" to handle the insane rotational speeds of the gyros in the system. I still have dreams (nightmares?) of the labyrinth of servos, synchros, roll/pitch resolvers and otherwise magical forces that kept that little "R2D2" pointing our boat in the right direction.. As an aside, My boat was one of the first to upgrade from the original SINS (Ships Inertial Navigation System) to ESGN (Electrically-Suspended Gyro Navigation) system. A quantum leap in capability
Worked in the Navy on the Litton ASN 42. Had a great record for accuracy by adjusting the peramitors to within plus or minus 3 millivolts rather than the accepted 6 millivolts.
I've been re-watching loads of stuff on the Apollo Guidance Computer (courtesy of the marvelous Curious Marc & team), and saw an interview with the guys who were programming the orbital dynamics. With the data from the inertial guidance system, after going through an ADC, they were able to "Easily" control the individual thrusters, and everything from pitch, yaw and roll to when the engines would fire. The system had one little wobble on Apollo 11, saved by Neal Armstrong's manual pilotage skills, but from then on, the system never put a foot wrong. Simply incredible engineering.
The "little wobble" was due to the Rendezvous Radar being left on during the decent portion of the moon landing. The computer did not have enough "through put" to handle THAT... AND... the complex calculations needed to perform the landing. It sent out an error code saying: "You're overwhelming me with work. I can't handle all of it". When the Rendezvous Radar (which is not normally used during descent) was turned off...the computer complaining went away.
I also heard that Armstrong had to take control to avoid a field of large rocks which may have damaged the LEM if a landing was attempted in that area.
I do not understand why you do not have more regular viewers of your videos! They're correct duration, well researched, interesting and most of all informative. I would expect over a million each video. Keep it up.
It's always a good day when I see one of your videos is up. Interesting and informative too. I imagine it takes quite a bit of time to research and put together one of these. Thank you for all your effort. I really enjoy these.
Nice summary. Inthe early '90's, I worked for a defense contractor manufacturing solid state accelerometers and gyros (rate sensors). Even back then, each sensor was packaged in a container the size/shape of a wrist watch. Now, commercial grade sensors are far smaller. Military grade sensors survive and maintain accuracy far better regardless of temperatures, vibrations, shock, EMI, etc. Ours were tough enough to be fired out of a cannon. We also made the first rate sensors for enhanced skid control in GM;s Corvette's and Cadillacs (~'92?). Solid state accelerometers and especially rate sensors commonly measure changes in frequency, displacements, etc. of vibrating MEMS structures. I think the most accurate ones use fiber optics.
"thank our patrons for thier [sic] support" & the plane showing testing the inertial guidance system across the country is not a B-29, as said in the narration, it is a cargo plane developed from the same main components but a much larger fuselage with two levels and a pinched waist. Don't recall its designation offhand
I have always wondered how the worked, in more depth than just a sentence or two. Thank you! Well done, it was excellent! Amazing how far it has come to that tiny device at the end.
It’s incredible to think that this exact or at least similar technology has been so miniaturized and advanced to the point that a solid state form of it fits into every single one of our portable electronic devices.
You get what you pay for there. The small devices drift significantly however GPS aiding cures a lot of ills. So low quality gyros like FOGs and accelerometers that were junk in the earlly 80s could be used with GPS to correct the drift and model the sensor errors. In a high jamming environment the drift rate of these devices becomes quite high.
As a USAF navigator who predated GPS integration, I found this very interesting. Maintaining vertical is indeed paramount, a parameter established during initial alignment, along with latitude. Knowledge of the Schuler Cycle was required for calculating the intervals between position updates, whether by radar, VOR/VOR, VOR/TAC, DME/DME and even celestial.
Great work! I plan to use this video for my physics classes when I teach rotational motion unit. Also, a newer application of this is the seakeeper gyro stabilization system used on boats!
Superb subject matter Paul, delivered in your usual interesting and professional style. Over the last 30 years working on light aircraft, I have seen general aviation aircraft navigation systems progress from 'steam-driven' (not actual steam, but an engine-driven vacuum pump) mechanical gyro units through to the MEMS-gyro electronic displays we have today. Inertial navigation was too complex a system to make it 'down' to my world, but gyro's remain a fascination for me. Thanks Paul, I hope you are well, and Happy Christmas 🎄🍻
From an aviation context, I have never seen such a thorough introduction to Inertial systems and their story. Thank you! As well stated in the video, INS systems nowadays are eerily accurate. Example of this is the GOL 1907 midair collision (INS was accurate enough to be kind of a contributing factor).
Absolutely fantastic! I remember the 'black boxes', which were the laser IRS on aircraft in the 90s, quite big by then...I would like to know how laser inertial systems work.
You split a laser in half, each beam do a semi circle in one direction. Then you shoot both beam into a sensor and you calculate the interference between them. If the compass isn't moving each beam travels the same distance and there is no interference. Once you start turning, one beam is gonna have a longer path and you have interference.
@@ameunier41 split, ok. In a semi-circle? A laser? A triangle perhaps. The interference phenomenon, as a means to measure the displacement is a cool technique.
A Laser ring gyros is built on a triangular piece of glass. It works like an inferometer to measure rotation about its center axis by measuring the frequency shift of the two laser beams. I’ve seen the production line and it is mind-boggling how they are manufactured in terms of tolerances of the glass body and the drill holes.
I appreciate all of your programs, but this is some of your best work. Covered much I didn’t know, explained the hard parts very well. However, it was inspiring to see the path from ancient mariners to my iPhone. Thank you.
I worked on the Sperry AN/WSN-7 Inertial Navigation System in the US Navy. It featured a 3 axis Ring Laser configuation. Once set at port, it was extremely accurate, but was fined tuned by GPS updates. I had a NASA Grace gravity map in my shop, as changes in gravity would affect the system - I had to mangage filters and dampers to correct those effects. There is still a huge negative gravity void in the Indian ocean, where the sub-continent used to be.
The Delco Inertial Naviation systems that came after the first Draper model were much smaller and were first put on Boeing's 747 in 1968. The Apollo program also used slightly larger gyros to accomplish it flights to the moon. Later (in the 1970's) several American military aircraft: the C-141, C-5 and the KC-135 had the same Inertial Navigations systems installed. New technology gyros in inertial systems are used on MANY deep space satellites.
On my way to a job with the airlines. I flew the DC-3 and the C-46, both were hand flown with no autopilot and no radar. A flight to Detroit to Dallas was a long 8 hours. If we flew Part 91 back it was a very long day.
This was a revelation to me. I only vaguely understood how these systems worked until now. Great video once again. I would love a follow up which dives into the development and functioning of the electronic navigation devices.
I recall when Qantas introduced INS to the B707 aircraft. The box about the size of a small refrigerator was located at the forward end of the forward cargo compartment. Interesting times. Navigators were retained for several years later but were on standby, some for around seven years.
INS is a system independent of the autopilot, though it may be used in conjunction with one.by WW2, autopilts were capable of flying a heading, and even tracking some radio navigation systems. INS merely replaced those radio or gyro held bits of info.
During the 1970s I flew a number of tactical aircraft for which a single analogue INS was the primary navigation aid. Even then they were remarkably accurate and reliable. Typically present position drift rates were better than 1nm/hr. These early systems were fairly clunky analogue systems with lots of moving parts. Since then there have been many improvements. Modern INS are fully digital and essentially solid state with few if any moving parts with all the mechanical functions reduced to mathematical algorithms running in a computer. A computer card incorporating a fully functional INS chip can now be purchased for as little as $1,000.
Learn more in 20 mins with this video then most textbooks. Remeber the L1011 used lasers or light in thier internal nav system. And that was in the late 70's early 80's
8:10 - bit of a correction. A gyro (an ideal one, anyway) doesn't sync to the ground where it was first spun up. Rather, it remains aligned to the "fixed" stars. So as the earth rotates, an ideal gyroscope will remain pointed at some fixed place in distant space, even if the gyro itself doesn't move (or fly) at all. This is actually a conundrum in physics, as we have no satisfactory explanation as to why there is a preferred frame that a gyroscope can align itself to.
Yes, it is affected by both, but the changes in angle induced by those two movements are tiny compared to the change induced by Earth’s spin on its axis.
There is another aspect of inertial reference systems that is not addressed here. That is the ability to make a fundamentally unstable aircraft stable. This is very useful in high dynamic flight such as a fighter.
I knew a man who was of the engineers of Wernher von Braun's V2 rocket. He worked on the rocket's gyro system in 1944. Gyros were invented by Anschütz 1908 in Germany.
I just got my Dynon D3 attitude gyro. Used in place of the mechanical gyro indicator that are prone to failure in airplanes. $800 bucks. Also has GPS and sim of topography. You don't want to fly into a mountain. Critical when there is a cloud in your wind screen.
Detector unit, DU unit, to keep it referenced to magnetic north, too. Compensation added/deducted for true north. Coreolis affect compensation too, round Earth etc..
Interesting, somehow I'd missed the history of inertial guidance pre Apollo. At least that was mostly figured out before then. I had always assumed it was developed for Apollo. I watched a video of how the gyros were calibrated to the launch pad while moving around from the wind. Seems like a much more exciting time for engineering than today
Modern maned aircraft and large UAV's Inertial navigation system use Ring laser gyro's not MEM's, these are used on cheep drones with a short flight times as they suffer more drift than Ring laser gyro.
Flew with the litton LTN-51 in alaska in a cessna 402. 747 was the first to use the system. We could fly for 6 hours and we were within 600 feet. 1970 ish.
One of the very earliest star tracker, but it seems it was lost in the shuffle. If only they would have stuck with that. A star tracker was used in the Navajo missile program, to fly to it's destination. The same star tracker with updates would be used in the SR-71. Thanks Paul.
Nowadays, all INS are updated by GNSS (GPS and other), which became a problem after cases of GPS signal Spoofing in Ukraine and Middle East. Honeywell released they are developing a INS based on Celestial Star Tracking as a backup to GPS.
Among other things, this helped, maybe even allowed, the Nautilus to cross from the Pacific to the Atlantic while continuously submerged under the polar sea ice and have a very good idea where they were then surfaced.
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That was a DC-3 camouflaged as a B-29.
Thanks for your research into this fascinating technology, Paul. 🙂👍
So.. in Apollo 13 is this the "gamble lock" they are talking about? (I might delete this by end of the video - 5:37 I think that was my clue but not a full answer lol)
@@jackbarnhill9354 Nope, it was a C97. DC-3's a tail dragger..
You shill worthless VPNs? So you don't respect your audience?
Ex Naval Weapons Engineer here. A key feature of these gyro's when used as a compass is that they apply the coriolis effect to find north. The earth's rotation caused the gyro axis to move relative to the earths surface. This movement was inside a control system loop that applied precession to keep the gyro axis pointing to true north. If the earth was flat, gyro based navigation systems would not be able to find north. They would not work.
As a 1960 Fire Control Technician aboard the SS 311 Archerfish, I could never get an answer as to how the submarine’s gyro established true north. Thank you for answering the question, “coriolis effect.”
The gyros had a method of applying and adjustable torque to the gyro. The torque was adjusted for latitude. Zero torque at the equator. Max torque at the poles. The correct torque caused the gyro to precess to keep it horizontal to the earths surface and pointing north. This was the open loop adjustment. Fine errors were detected and minimised with the closed loop control system. At least that is what I remember from the 1990's @@MikeCasey311
Much to the frustration of the flat earthers !! Lol
@@MikeCasey311 On old gyro compasses, the Gyro Tech hangs weights on the gyro to precess the gyro at a rate that matches the earths rotation and keeps the gyro axis parallel with the earths surface. The weight depends on the latitude. Zero weight at the equator where the gyro axis of rotation matches the earths axis. This is open loop control. The closed loop control system is north seeking and does the fine adjustments.
@@darrenconway8117 Thank you, from Mike Casey FT2 SS.
On the Apollo program, just before a mid-course correction burn, the astronauts would use a telescope to orient the "stable member" (the platform that held the gyros and accelerometers) to an orientation fixed in space. They would then maneuver the orientation of the space craft (in pitch, roll and yaw) around that "stable member"...using it as a reference. The Apollo Guidance computer would tell the astronauts the exact pitch, roll and yaw to obtain in order to accurately orient the command module for what was called a "Delta V" engine burn. That "Delta V" maneuver was a short burn of the CM's main engine and/or the small thrusters on the side to make the necessary flight corrections to obtain the proper orbit around the moon.
The Space Sextant
Thank you for the response. Some say after the Apollo program we lost the technology to get to the moon. It's my knowledge that it was less about the technology and more about how the craft navigated there and back. Some of these shortcuts are just now being declassified like you just discussed.
Used to service Sperry rate gyros for F-4 Phantoms, three on each aircraft - roll, pitch and yaw. Simple things. Take them to bits, change bearings and balance the wheel and back together, gas fill and test. Magnetic field damping using a copper vane they had.
I got to see (and tinker with) a working museum model of that system last summer... Blew my mind to say the least...
Gas filled? Helium or nitrogen?
@@davidg3944I think the goal is to reduce friction, so I would go with helium, just like newer hard drive.
As an Electronics Engineer, in the early 80's I was delighted to be given a guided tour of a 747 aircraft. All these planes were equipped with Inertial guidance (INS) from the start. The INS was HUGE - and heavy. In recent years I have been routinely designing in tiny 9 axis (accelerometer, gyro, magnetometer) chips into products. MEMS devices have had an enormous effect on general life for most people who are technology connected, but very few appreciate just how mind-blowingly significant such devices have become.
I am now retired but still vividly recall the 747 INS as a stark contrast to the near equivalent parts I need reading glasses to see nowadays.
Great doco' Sir. Thank you.
Yea, old Sperry, King's,LN1-LN3..
Another intelligent, interesting and educational video. Thank you. Why a TV production company haven’t snapped you up is beyond me. Your presentations are leaps and bounds beyond what I’ve seen put out by the BBC, Sky etc….
When I was young in the Navy, worked on Sperry gyrocompasses (Mk 19 and Mk27). Two gyros inside, electrolytic levels, lots of servos and mechanical integrators. Fascinating bits of machinery that could find true north from just about anywhere as well as provided a stable roll/ pitch reference to feed into fire control systems.
the 19 did it all, the 27 was just heading.
An old friend of mine was a second then first officer then captain and later fleet manager of the BOAC B707, he told me that before the CAA would allow such a high tech device that frankly they didn’t understand aboard a British registered aircraft it would need thorough testing. A B707 was used and a discreet portion of the forward hold was used to house the device, for 6 months before every flight a white coated technician would crawl into the hold, open a locked door and perform what we now refer to as the alignment, the door was then locked again and at the end of the flight another white coated technician would crawl back in and take some readings, before the whole process was repeated again. The crew had no access to the output of the thing in the hold therefore it was still down to the second officer (nav) to use dead reckoning, star shoots, loran C and other basic navigation aids to provide a position known as a “cocked hat” where the aircraft was basically somewhere in the middle. That little box in the forward hold would eventually make the poor old second officer position obsolete but at that time he was the busiest guy on the flight deck.
Impressive use of four periods!
Pea. ess.
How old is your friend?
@@CallMeByMyMatingName unfortunately he’s no longer with us, when I knew him he had not long stopped flying commercially, that was in 1986 by then he was in his early 60’s, by the time I lost touch with him in the mid 90’s he had had a couple of cancer scares and died a few years later. While everybody in aviation thinks they lived through the golden age (me included) I really think he did, he joined BOAC on the Lockheed Constellation then on to the Bristol Britannia, after a short period he joined the B707 fleet until they were retired. He was then offered a short term contract flying a small fleet of B727’s leased from Branif until he scored his dream type, the Concorde. He flew her for his last few years in BA as they had a retirement age of 55 in those days, but was able to pick up some contract work on the B727 until he had to finally hang up his wings.
I joined BOAC in 1971 and flew the B707 until 1978. I recall when dual inertial nav systems were retro fitted to the aircraft and it was the best thing since sliced bread! This meant there was no longer any requirement for a flight navigator on oceanic flights so the minimum crew became 3, ie Captain, First Officer and a Flight Engineer. But more importantly it brought the navigation on long overwater flights "in view" of the pilots whereas before the Flight Navigator would have been beavering away with charts on the flight nav table behind the pilots.
All waypoints (maximum 9) had to be inserted manually into the inertial units as lat and longs so it was important to crosscheck tracks and distances to verify the correct positions had been loaded. As you flew along the route and passed waypoints you'd be loading the waypoints further along the route - good game!
I can't recall whether it was west or eastbound but terminal errors were higher going in one direction due earth's rotation but final errors at end of an atlantic crossing would only be a few miles. You could also update position at the end of the crossing by accurately overflying a ground based radio beacon and when right overhead pressed an appropriate button and load the charted position of the radio beacon.
At the end of the flight terminal errors were recorded for the airline nav dept and engineers to monitor performance.
One revelation is that before inertial nav aircraft over the oceans were often 30 or 40 miles off track. When inertial came along you'd be halfway across the pond and actually see opposite direction traffic (at least 2,000 feet above or below) go right over or below you - something we rarely saw before!
Also the extra accuracy meant that separation over the pond could be reduced which increased the flow rate on routes.
@@fireflyrobert it really was a time of rapid advances, I did my ATPL writens in 1986 and by then the CAA felt that they must add some questions about these new fangled INS thingies so I got about 5 questions mostly odd unpractical stuff in my instruments paper, unfortunately they were a little behind the times as by then the INS had been phased out in favour of the IRS system. My first Jet was the DC9, I joined the fleet in late 88 and left it in early 95, as it was basically a Cherokee with JT8D’s it had no long range nav kit at all, when I first flew the thing nobody really minded you being a few miles off course but by the end of my time on her ATC had got used to all the other aircraft going where they were told to so we would often be changed from making our own way to being given steers.
I consider myself lucky that I’ve gone from the Do228 to the F27, then the DC9 followed by the B737, after that my long marriage with Airbus flying the A320 family and the A330 before landing the queen of the skies the B747-400, that would’ve been enough and to be honest after the Jumbo was rudely retired early I thought that that was it? But again luck has stepped in and I find myself doing my last few years on the A350.
The changes along the way have truly been remarkable and not just the technology on the aircraft but the airspace changes also.
I wonder what another 30 years will bring?
@@johnmorris7815 in many ways your career and experience echo mine. The advances we have seen in our careers have been quite remarkable. As you say what's coming in the next few decades?
I’d have to say that I’ve never disliked one of this channel’s videos. This video is new and already amongst the favorites I have! Extremely informative and entertaining! Keep up the great work, Paul!
I just watch to see his shirts!
Let's see how many times you'll be willing to listen about Nord VPN.
@@j7ndominica051 Eh, at least it's not cigarette advertisements... :)
Just stumbled across this channel. If you're interested: (Google) Autonetics / Anaheim ,Ca. At it's peak, the facility employed 36,000 people in Orange County - down the road from Disneyland. The facility was huge (Calisphere /images)
It was flown in a Boeing C-97 stratofreighter which shared the wings, engines and tail with the B-29. This system is covered in detail in the Apollo Guidance Computer episode of Moon Machines that was on the Science Channel
Great episode indeed.
I was wondering about that since the opening sequence did show a C-97, but a bit later showed a clip of a B-29.
The AGC and it's software is just...
😚🤌
You are legitimately my favorite TH-cam creator. Your delivery is smooth and easy to digest. Always instant click when winding down after a busy day. Thank you for your time and education, SIR!
Do you have an illegitimate favorite as well?
Back in the late 1940's these mech gyros and systems were found in surplus stores in LA such as Palleys; we got our hands on some of these devices, they were mesmorizing to us youngins.. In the early 1960's with a tech degree, worked for Autonetics on INS; Polaris N7F, A-4 (Skyhawk?), MM II, all in a one secured double-building. Semi conductors were already used heavily at this time, the INS integration was mind-blowing. Tektronix at this time was also integrating their front-end amplifiers with semi-conductors the first being the Tek 547 O'scope.
A former colleague worked for both Autonetics and Sperry on INS systems for aircraft and submarines.
Had some interesting stories about slight initialization inaccuracies causing major drift in courses: one was caused by failure to compensate for the slight twisting of the carrier deck while sending starting point coordinates from the INU on the bridge to the unit on the aircraft.
He was also involved with the electronic systems integration on the B-58 Hustler program.
(I worked with him much later, outside of the defense sector.)
I had a friend who scavenged all the microwave surplus he could grab after the war. He knew what he was looking for, and found stuff in the surplus stores that nobody else would recognize, know how to wire up, or apply to anything... He was lighting gas tubes 8 feet away from his various microwave generators. The lights would dim in his house when he powered stuff up.
The prospect of the Gyro theory module was always the one more senior courses used to 'scare' us during my Artificer Apprenticeship training as a Weapons Engineer in the Royal Navy.
This video is an order of magnitude more fascinating than the raw maths, I can confirm.
As an air-nav junkie, this is an early christmas present. The amount of innovative navigation techniques and systems from the 40s to the 80s before GPS was the standard is phenominal. Great choice of topic.
GPS is still combined with inertial for most commercial aviation systems. GPS on its own isn’t reliable enough.
It makes sense and really underlines the importance of maintaining this type of knowledge, making sure it is not lost...perhaps developing it further. Who knows what may become possible in the future? I am struck by the intelligence of design found in these older ways and in the overall evolving of the ways we investigate the laws of physics to navigate.
As a side note, I wonder if human powered flight will ever be possible, in some sort of way to fly like a true bird!
@@peteconrad2077im fairly certain submarines still use inertial navigation when underwater and then get a gps correction everytime they surface or pop a radio antenna up etc.
@@kizzjd9578 in sure they do. Although there could be a vlf or elf nav network we don’t know about.
@@kizzjd9578I believe that this use was actually the use that started what has become GPS.
My Gandfarther worked for Sperry during WW2 in the UK (He had a protected occupation). He made the Gyroscopes that were used in ships and on planes for the war effort. Fascinating episode, we are all today standing on the shoulders of giants
you are standing on the shoulders of idiots who destroyed their own people
For about a year around 1974 I worked for Ferranti in Edinburgh where they were developing the Inertial Navigation system for the Panavia Tornado. An amazing electrochemical bit of kit.
When I was doing a student apprenticeship with a uk defence electronics company in the early 1960’s we used solid state analogue electronics and miniature gyros (I had the same gimbles as a record player arm support) and it was tested by going round and round the Glasgow subway and achieved an amazing accuracy over a days travel in both directions.
I worked on the F111 and it was one of the earlier aircraft to use innertail navigation.
Even in 1973, the inertial navigation assembly cost over 1 million dollars
Excellent coverage - I worked on analog and digital Inertial navigation systems(INS) in the U.S.A.F and remain absolutely amazed at how well they work. We depend too much on gps and should retain INS technology in newer applications.🧑🔧
I've heard that consideration is being given to updating and re-activating a number of LORAN stations in case GPS satellites are damaged or destroyed by EMP or radiation beams from space-based assets of rogue nations.
what a wonderful episode, something I have wondered about for 50 years....thank you....
I follow several technology and history channels, I guess this is a combination of the two. Your videos are very relaxing and informative. It's always presented a and very easy to follow. Presented slowly and steadily with great visuals, it gives us time to really absorb and appreciate the presentations.
You never, ever disappoint Paul! WELL DONE AGAIN!!!
I used to work at MIT, where among other things I worked on components for small satellites. I spent at least ten days at Draper Lab in their vibration test facility, having assemblies tested on their sinusoidal sweep equipment so that what I'd made could go through an equivalent of the forces encountered during a rocket launch.
Along with that, I had a friend whose father hard worked there, and at some point years ago I was given a memento from the dad's workdays - a gyroscope housing. I don't have much knowledge of where it was used but given its size (a bit smaller than a basketball) I'd guess it was for early (1960's) missile...
Fascinating! It would be interesting to know more about the laser-based accelerometers and gyros used on planes today.
3:02 video starts if you want skip the intro and VPN advert
This type of system was on the sub that I served on for 4 years. I ran this system which ours was the upgrade to this system. It really worked well and we had a total of 3 redundant systems. SO if one broke the 3 others took over and you could also compare the 3 systems. It was really cool and this was back in the 1980s.
a brilliant doco thanks. that answered many questions for me, cheers from NZ
This is a good amount to take in. I know I appreciate having piezoelectric gyros on my 3D RC choppers. Without them, it would be nearly impossible to keep any sort of heading.
Forget heading. Stability period would be impossible.
@@MadScientist267 Same thing. It uses internal inertia references to make course correction adjustments so that the primary changes come from the controller.
@@BigMobeItt having the pusher same in you
@@MadScientist267 It isn't impossible. Lots of RC choppers flew before those micro gyros were available. It just takes skill.
@@prophetsnake Reading comprehension... 🤦♂️
Mk-19 Gyrocompass Tech. First encounter with "Synthetic Lubrication" to handle the insane rotational speeds of the gyros in the system.
I still have dreams (nightmares?) of the labyrinth of servos, synchros, roll/pitch resolvers and otherwise magical forces that kept that little "R2D2" pointing our boat in the right direction..
As an aside, My boat was one of the first to upgrade from the original SINS (Ships Inertial Navigation System) to ESGN (Electrically-Suspended Gyro Navigation) system.
A quantum leap in capability
Worked in the Navy on the Litton ASN 42. Had a great record for accuracy by adjusting the peramitors to within plus or minus 3 millivolts rather than the accepted 6 millivolts.
I've been re-watching loads of stuff on the Apollo Guidance Computer (courtesy of the marvelous Curious Marc & team), and saw an interview with the guys who were programming the orbital dynamics. With the data from the inertial guidance system, after going through an ADC, they were able to "Easily" control the individual thrusters, and everything from pitch, yaw and roll to when the engines would fire. The system had one little wobble on Apollo 11, saved by Neal Armstrong's manual pilotage skills, but from then on, the system never put a foot wrong. Simply incredible engineering.
The "little wobble" was due to the Rendezvous Radar being left on during the decent portion of the moon landing. The computer did not have enough "through put" to handle THAT... AND... the complex calculations needed to perform the landing. It sent out an error code saying: "You're overwhelming me with work. I can't handle all of it". When the Rendezvous Radar (which is not normally used during descent) was turned off...the computer complaining went away.
I wonder if they missed a checklist item...or if it was not on the checklist.
@@badguy5554
I also heard that Armstrong had to take control to avoid a field of large rocks which may have damaged the LEM if a landing was attempted in that area.
I do not understand why you do not have more regular viewers of your videos! They're correct duration, well researched, interesting and most of all informative. I would expect over a million each video. Keep it up.
People don't want to learn as much as being simply entertained.
It's always a good day when I see one of your videos is up. Interesting and informative too. I imagine it takes quite a bit of time to research and put together one of these. Thank you for all your effort. I really enjoy these.
I love how your videos show the importance of the history of technology. There isn't enough awareness of this.
Nice summary. Inthe early '90's, I worked for a defense contractor manufacturing solid state accelerometers and gyros (rate sensors). Even back then, each sensor was packaged in a container the size/shape of a wrist watch. Now, commercial grade sensors are far smaller. Military grade sensors survive and maintain accuracy far better regardless of temperatures, vibrations, shock, EMI, etc. Ours were tough enough to be fired out of a cannon. We also made the first rate sensors for enhanced skid control in GM;s Corvette's and Cadillacs (~'92?). Solid state accelerometers and especially rate sensors commonly measure changes in frequency, displacements, etc. of vibrating MEMS structures. I think the most accurate ones use fiber optics.
"thank our patrons for thier [sic] support" & the plane showing testing the inertial guidance system across the country is not a B-29, as said in the narration, it is a cargo plane developed from the same main components but a much larger fuselage with two levels and a pinched waist. Don't recall its designation offhand
I'll give you this, CD: of all the tech blather on TH-cam, yours is the most accurate and error-free.
Thank you.
I have always wondered how the worked, in more depth than just a sentence or two.
Thank you! Well done, it was excellent!
Amazing how far it has come to that tiny device at the end.
It’s incredible to think that this exact or at least similar technology has been so miniaturized and advanced to the point that a solid state form of it fits into every single one of our portable electronic devices.
You get what you pay for there. The small devices drift significantly however GPS aiding cures a lot of ills. So low quality gyros like FOGs and accelerometers that were junk in the earlly 80s could be used with GPS to correct the drift and model the sensor errors. In a high jamming environment the drift rate of these devices becomes quite high.
Wow……..what an amazing story. The discoveries of scientists like this are truly miracles! Great video!!
Definitely an amazing story and definitely a great video, but also definitely not a "miracle".
As a USAF navigator who predated GPS integration, I found this very interesting. Maintaining vertical is indeed paramount, a parameter established during initial alignment, along with latitude. Knowledge of the Schuler Cycle was required for calculating the intervals between position updates, whether by radar, VOR/VOR, VOR/TAC, DME/DME and even celestial.
Great work! I plan to use this video for my physics classes when I teach rotational motion unit. Also, a newer application of this is the seakeeper gyro stabilization system used on boats!
Superb subject matter Paul, delivered in your usual interesting and professional style. Over the last 30 years working on light aircraft, I have seen general aviation aircraft navigation systems progress from 'steam-driven' (not actual steam, but an engine-driven vacuum pump) mechanical gyro units through to the MEMS-gyro electronic displays we have today. Inertial navigation was too complex a system to make it 'down' to my world, but gyro's remain a fascination for me. Thanks Paul, I hope you are well, and Happy Christmas 🎄🍻
I have been watching your channel for years. This has to be the best and most interesting subject you've posted for my taste. Great job!
From an aviation context, I have never seen such a thorough introduction to Inertial systems and their story. Thank you!
As well stated in the video, INS systems nowadays are eerily accurate. Example of this is the GOL 1907 midair collision (INS was accurate enough to be kind of a contributing factor).
Absolutely fantastic! I remember the 'black boxes', which were the laser IRS on aircraft in the 90s, quite big by then...I would like to know how laser inertial systems work.
You split a laser in half, each beam do a semi circle in one direction. Then you shoot both beam into a sensor and you calculate the interference between them. If the compass isn't moving each beam travels the same distance and there is no interference. Once you start turning, one beam is gonna have a longer path and you have interference.
@@ameunier41 split, ok. In a semi-circle? A laser? A triangle perhaps. The interference phenomenon, as a means to measure the displacement is a cool technique.
A Laser ring gyros is built on a triangular piece of glass. It works like an inferometer to measure rotation about its center axis by measuring the frequency shift of the two laser beams. I’ve seen the production line and it is mind-boggling how they are manufactured in terms of tolerances of the glass body and the drill holes.
I appreciate all of your programs, but this is some of your best work. Covered much I didn’t know, explained the hard parts very well. However, it was inspiring to see the path from ancient mariners to my iPhone. Thank you.
I worked on the Sperry AN/WSN-7 Inertial Navigation System in the US Navy. It featured a 3 axis Ring Laser configuation. Once set at port, it was extremely accurate, but was fined tuned by GPS updates. I had a NASA Grace gravity map in my shop, as changes in gravity would affect the system - I had to mangage filters and dampers to correct those effects. There is still a huge negative gravity void in the Indian ocean, where the sub-continent used to be.
10:34 This, and the aircraft at the beginning of the video, is a C-97, a cargo adaptation of the B-50 bomber
Great timing with Scott Manley's show on submarine missiles
Dr Draper was highly involved in the Apollo Guidance Computer (AGC). Also he developed a clever backup solution. Very well researched video
This channel is never short on quality content we expect. Thanks a lot
The Delco Inertial Naviation systems that came after the first Draper model were much smaller and were first put on Boeing's 747 in 1968. The Apollo program also used slightly larger gyros to accomplish it flights to the moon. Later (in the 1970's) several American military aircraft: the C-141, C-5 and the KC-135 had the same Inertial Navigations systems installed. New technology gyros in inertial systems are used on MANY deep space satellites.
Paul, nice vieo on the development of inertial guidance. (I see someone else spotted to mislabeled "B-29")
On my way to a job with the airlines. I flew the DC-3 and the C-46, both were hand flown with no autopilot and no radar.
A flight to Detroit to Dallas was a long 8 hours. If we flew Part 91 back it was a very long day.
This was a revelation to me. I only vaguely understood how these systems worked until now. Great video once again.
I would love a follow up which dives into the development and functioning of the electronic navigation devices.
The missile knows where it is because it knows where it isn't...
I recall when Qantas introduced INS to the B707 aircraft. The box about the size of a small refrigerator was located at the forward end of the forward cargo compartment. Interesting times. Navigators were retained for several years later but were on standby, some for around seven years.
INS is a system independent of the autopilot, though it may be used in conjunction with one.by WW2, autopilts were capable of flying a heading, and even tracking some radio navigation systems. INS merely replaced those radio or gyro held bits of info.
nice film Paul.
Love your videos. So informative. Learn something new every time I watch one.
Thank you for the video lecture, interesting and thank you to Dr. Draper for his contribution to the Inertial navigation system.
One of the first INS was installed in SSN 571, USS NAUTILUS, to sail under the North Pole's ice pack.
Greetings from Patagonia, Argentina ! 🇦🇷
A nice intro into the history of aerospace tech. Great video, I'll be coming for more.
That's +1 to your fleet of subs!
Brilliant as always thank you 👍
Took me 3 minutes to gather myself afterward Droid. Oh boy you did it again. Thanks.
During the 1970s I flew a number of tactical aircraft for which a single analogue INS was the primary navigation aid. Even then they were remarkably accurate and reliable. Typically present position drift rates were better than 1nm/hr.
These early systems were fairly clunky analogue systems with lots of moving parts. Since then there have been many improvements. Modern INS are fully digital and essentially solid state with few if any moving parts with all the mechanical functions reduced to mathematical algorithms running in a computer. A computer card incorporating a fully functional INS chip can now be purchased for as little as $1,000.
Thanks for the presentation very interesting and enlightening
Such a great interesting video.
Thank you for this awesome informative channel. 👍💪😎
I am very impressed by the quality of this video. My compliments!
Learn more in 20 mins with this video then most textbooks. Remeber the L1011 used lasers or light in thier internal nav system. And that was in the late 70's early 80's
8:10 - bit of a correction. A gyro (an ideal one, anyway) doesn't sync to the ground where it was first spun up. Rather, it remains aligned to the "fixed" stars. So as the earth rotates, an ideal gyroscope will remain pointed at some fixed place in distant space, even if the gyro itself doesn't move (or fly) at all. This is actually a conundrum in physics, as we have no satisfactory explanation as to why there is a preferred frame that a gyroscope can align itself to.
Modern version of the voyages with John Harrison's H4 timekeeper?
Always a good day when you post another video.
Good to see you Paul. Great content as always
Is the motion of the gyroscope affected by the movement of the Earth going around the solar system AND going around the Galaxy?
Yes, it is affected by both, but the changes in angle induced by those two movements are tiny compared to the change induced by Earth’s spin on its axis.
There is another aspect of inertial reference systems that is not addressed here. That is the ability to make a fundamentally unstable aircraft stable. This is very useful in high dynamic flight such as a fighter.
I knew a man who was of the engineers of Wernher von Braun's V2 rocket. He worked on the rocket's gyro system in 1944. Gyros were invented by Anschütz 1908 in Germany.
I just got my Dynon D3 attitude gyro. Used in place of the mechanical gyro indicator that are prone to failure in airplanes. $800 bucks. Also has GPS and sim of topography. You don't want to fly into a mountain. Critical when there is a cloud in your wind screen.
Detector unit, DU unit, to keep it referenced to magnetic north, too. Compensation added/deducted for true north. Coreolis affect compensation too, round Earth etc..
Thanks again, Paul, for antother interesting, informative and entertaining video!
They cover this real well in the TV Series, Moon Machines. The Navigation Computer..
And Charles Draper had a nice humor about him.
The aircraft is a Stratocruiser, not a B29 bomber. Similar wings and such, but a different fuselage.
Interesting, somehow I'd missed the history of inertial guidance pre Apollo. At least that was mostly figured out before then. I had always assumed it was developed for Apollo. I watched a video of how the gyros were calibrated to the launch pad while moving around from the wind. Seems like a much more exciting time for engineering than today
Did the star navigation system of the SR-71 use neutron stars?
Modern maned aircraft and large UAV's Inertial navigation system use Ring laser gyro's not MEM's, these are used on cheep drones with a short flight times as they suffer more drift than Ring laser gyro.
1,800 kg of an inertial guidance system now is down to a few milligrams of accelerometers in my phone. Quite a change.
Your phone has no gyro system so it can’t really be used as internal nav.
@@peteconrad2077my midrange device purchased several years ago has gyroscopes.
That was an excellent explanation how an inertial nav. works.
Thumbs up.
…and subscribing…
As always, great job.
Great video as always, one of the best channels I follow.
That was a great video, I did not know we could make them that small.
Flew with the litton LTN-51 in alaska in a cessna 402. 747 was the first to use the system. We could fly for 6 hours and we were within 600 feet. 1970 ish.
is Romane lettuce the best choice to minimize the plant's narcotic properties
(they are thinking of growing a bunch of lettuce 'up in' space)
One of the very earliest star tracker, but it seems it was lost in the shuffle. If only they would have stuck with that. A star tracker was used in the Navajo missile program, to fly to it's destination. The same star tracker with updates would be used in the SR-71. Thanks Paul.
Excellent video. Thank you so much.
Best and most informative TH-cam channel
12:59 is that Robert McNamara on the left in the glasses?
Hanscom AFB isn't just near Boston, the base is in Concord, MA where the American Revolution began.
Nowadays, all INS are updated by GNSS (GPS and other), which became a problem after cases of GPS signal Spoofing in Ukraine and Middle East.
Honeywell released they are developing a INS based on Celestial Star Tracking as a backup to GPS.
Great guidance video, SSBN navigation is done by different contractors (Lockheed/Boeing)
Among other things, this helped, maybe even allowed, the Nautilus to cross from the Pacific to the Atlantic while continuously submerged under the polar sea ice and have a very good idea where they were then surfaced.