East is Least. West is Best.

[TheGreenGoblin]

In these days of Unmanned Autonomous Vehicles using sophisticated corrected inertial navigation systems it is easy to forget how far the the science of navigation of cruise missiles had come by the late 1950's.

With a hat tip to Doc Draper of Inertial Guidance System fame

Draper Labs were to design and build the on-board guidance systems on the Apollo moon missions.

This is the guidance system from the Snark, an air-breathing, subsonic, unpiloted winged missile built by Northrop Aircraft in the 1950s. The system used a combination of inertial and stellar techniques to navigate from launch points in the United States to targets up to 8,000 km (5,000 miles) away. The inertial system guided the missile during launch. Once the missile achieved cruising altitude, the system locked onto a star and corrected any errors in its trajectory caused by drifting of the gyros or other factors. For the final dive to the target, the inertial system once again took over.

The Snark was briefly deployed in the 1950's but was quickly replaced by ballistic missiles in the U.S. arsenal. The advances in stellar and inertial navigation developed for the Snark were later used on other aircraft, most notably the SR-71 Blackbird.

From the Smithsonian Museum site

Snark Missile

[Pontius Navigator]

TGG, today people marvel at the Bletchley bombes but don't see the other huge computing miles stones.

A Nimrod aircraft computer was 8 kb, 8kb compared with your cheap smart phone with a 128 Gb card.

A V-bomber computer weight 1,400lbs.

The fix reduction tables for an Omega fix would fill a bookcase.

Your car Sat Nav is already obsolete.

Who would willingly fit filament bulbs? (Though I keep a big box full for when I move house).

I remember composing email posts off line on CompuServe before going on line at 2.4 kbs and tying up a pay per call phone line when SWMBO wanted to use the phone.

When adults could operate a TV: it had one channel.

When you couldn't lose a TV remote; it was attached to the TV with a cable.

Music was stored on cassettes.

[TheGreenGoblin]

TGG, today people marvel at the Bletchley bombes but don't see the other huge computing miles stones.

You are quite right PN.

Yesterday I was looking at my tablet (not of stone but consisting of a lot of sand and germanium, namely my PDA) and noted that its functions include a digital accelerometer, gyro, barometer, GPS and magnetometer (not to mention the camera/scanner with optical recognition features). Therein being all the basic requirements for a GPS corrected INS in a plastic case weighing less than 800 grams.

Ok, I know that the scan sample rate of the accelerometer is too low and that the sensitivity of the one gyro too coarse for anything but a toy that is useful only for a journey around one's lounge and that it would soon drift over a journey over a mile or two, but I predict that within 5 to 10 years we will see usable multi-gyro INS systems appearing as apps on our digital devices.

In fact one can purchase useful portable digital INS systems for less than £3000 these days.

https://www.trimble.com/GNSS-inertial/index.aspx

Paul Simon was right when he wrote...

"These are the days of miracle and wonder
This is the long distance call
The way the camera follows us in slo-mo
The way we look to us all
The way we look to a distant constellation
That's dying in a corner of the sky
These are the days of miracle and wonder"

... although he saw a much darker significance in our techno-barbarity.

[Pontius Navigator]

Crikey, 800g, that is heavy.

You can get a 'communicator' that can do all that, beam moving pictures around the planet, store you library of books, and wear it on your wrist and weighing less than 50g.

My 'state of the art' wristwatch (10 years old now) can automatically correct its time using one of 3 low frequency broadcast signals. Later versions use one of 4. The most recent uses satellites.

Some watches can send an emergency signal anywhere in the planet.

What used to cost $sqn is now available from China for $$.

Just how many people in the world can actually design these things that we need mortals take for granted?

But there must be people now that cannot survive without the basics. I was in London during the public transport shut down of 7/7. I think taxis stopped too. Commuters used to travelling underground like moles were peering around trying to find a way home. I was much in demand for my bus map.

[TheGreenGoblin]

Crikey, 800g, that is heavy.

You can get a 'communicator' that can do all that, beam moving pictures around the planet, store you library of books, and wear it on your wrist and weighing less than 50g.

Definitely one too many 0's in my estimated weight, as you say PN.

[Undried Plum]

I worked on the seabed search & recovery of the Challenger Shuttle.

Our four priorities were, in order:

1) Human remains

2) the Starfix gizmo

3) The SRBs

4) the cargo

The Starfix gizmo was located just in front of the Captain's windscreen and was the same unit as in Trident nooqular mistles. We found it just after we recovered the human bits.

We never did find the cargo. It was a supersecret spy satellite, which is why they had the hoopla of the wumman schoolteacher to distract public attention while the in-orbit launch took place. Them pesky Rooskies had been waiting 'downrange' in a diver lockout sub just in case of such a crash. The barstewards had facked orf with the satellite by the time we got around to looking for it.

[Boac]

Not familiar with 'Starfix', UP - anything you can tell?

[Undried Plum]

There are actually two star tracking cameras pointed in orthogonal directions to eachother. It's quite old technology and by modern standards the sensor chips have quite coarse resolution, but it works and can produce a fix which is good to a hundred metres or so because the cameras have a very narrow field of view. The computer has the co-ordinates of all 57 navigational stars and uses them in pairs for orientation and a series of fixes to compute a position fix.

Trident uses INS for the climbout phase and then uses the star tracker(s) for orientation and navigation for the 'cruise' phase to correct its trajectory to the target before launching the MIRVs. If it starts tumbling in flight it's buggered as it needs to know, within a degree and a half, where to look for a particular star. It doesn't use GPS at all because the NavStar constellation wasn't yet usable when Trident was being developed and the old Transit system wasn't suitable for that sort of task. Its predecessor Polaris was purely INS driven and had lousy accuracy

The Shuttle had the same unit as Trident. The two cameras were on a single elongated chassis which was machined to remarkable precision. Most of the navigation of that space vehicle was done from the ground and the Keppler parameters were telemeted to the onboard nav computer, so the StarFix system was mostly used for orientation of the vehicle.

The Soviets were, at the time, very keen to get hold of one of these things, particularly its firmware, as they wanted to improve the accuracy of their own ICBMs so they could whack individual Minuteman silos and command bunker adits.

[TheGreenGoblin]

A little bird has indicated that a plastic object related to navigation might be in the offing as a birthday present next week. I am agog with excitement.

[Boac]

Get it soon, then, 'cos I believe the poles will flip sometime soon - no, not the immigrant workers...

[barkingmad]

The most interesting and quirky pieces of navigation equipment were often seen embarking/disembarking from a Dominie.........

[TheGreenGoblin]

I chose on the basis of Fox3's advice. I trust she has abided with that. Whatever the case I will be pleased, not least because my life will depend on it...

[Sisemen]

As a 15 year old attending the Introduction to Mountaineering course at Plas y Brenin in Snowdonia I was taught MUGS and GUMA. Magnetic Unto Grid Subtract, Grid Unto Magnetic Add. Stuck with me ever since.

[Sisemen]

As a 15 year old attending the Introduction to Mountaineering course at Plas y Brenin in Snowdonia I was taught MUGS and GUMA. Magnetic Unto Grid Subtract, Grid Unto Magnetic Add. Stuck with me ever since.

Edit: I also acquire the knack of coming into a thread years and years behind everyone else