SatNav of the future?

Galileo satellite in orbit.

I always love it when the more theoretical aspects of physics, so often the exclusive realm of mathematicians and those studying the origins of the universe, have a direct impact on our daily lives. 

Take the GPS system, for example, which has so many challenges that it really shouldn’t work at all, as far as I can see.   Quite apart from the very clever software and signal-processing needed to allow a weak radio signal, from a satellite tens of thousands of miles above you, to be diluted over a substantial chunk of the earth’s surface, and distorted by the ionosphere, and compromised by the weather, yet still be picked up by a small battery-powered device in your pocket when you’re sitting inside a moving metal box surrounded by lots of other noisy electrical signals… quite apart from all that, there’s another problem… and it involves Einstein.  

Did you know you were using his Theories of Relativity whenever your satnav tells you how far it is to the next junction?    I’ve always found this very pleasing.

GPS depends on being able to make very accurate time measurements, and the issue is that the satellites are travelling very fast, which means that time itself runs at a different rate for them than it does for the those of us down below driving round the M25. Their atomic clocks run more slowly than an equivalent on Earth.  But a bigger effect comes from the fact they’re in a lower gravitational field, which causes them to run faster!  Pleasingly, this means that both Special and General Relativity need to be taken into account by the GPS system, in order to work out these differences and stop a gradual drift, which would be visible over time on your satnav map and might make you think you were on the wrong road.  Thanks for sorting that out, Albert!

However, for all the magic of GPS, it has its limitations, as you’ll know if you’re driving through a long tunnel, or between skyscrapers on the streets of Manhattan.  And the delicacy of the GPS signal also means that it can easily be interfered with by, for example, an enemy on a battlefield. When the GPS signal is lost, navigation systems have to fall back on ready-reckoning using accelerometers and distance measurements to try and guess where you are.  This is a process as old as navigation itself, but it is very fallible, because your knowledge of your current position is based on your position a little while before, and any errors in that process get magnified the further you go. The accuracy of accelerometers has greatly improved over time and become less dependent on things like the bearings of spinning gyroscopes, but it’s still a problem.  

This is why a lot of people are awfully excited about the recent experiments with Quantum Positioning, which may offer a much more accurate way to do this in the future (and I would guess may be useful long before quantum computing!)  Once again, theoretical physics may help us find out where we are.  It may be rather a long time before you have this mounted on your dashboard, but perhaps not so long until it’s in ships, submarines and aircraft.

So how do you use quantum mechanics to work out your position?  (Or, more precisely, your acceleration, from which changes in position can be derived?)

Fortunately, there’s a really excellent video by Ben Miles explaining the basics.  Nicely done.

Code Review

It’s easy for those of us who passed their UK driving test a long time ago to forget that the Highway Code is not a static document: it is updated from time to time and old drivers need to know about the changes as well as young ones.

For example, I didn’t know about all these changes in 2022, mostly to do with the interactions between different types of road users: drivers, cyclists, pedestrians and horse riders. Did you? They’re quite important.

Yesterday

I liked this Beatles tribute, reposted on Mastodon but, it appears, written originally by one Sunni Freyer in the late 90s:

YESTERDAY

Yesterday,
All those backups seemed a waste of pay.
Now my database has gone away.
Oh I believe in yesterday.

Suddenly,
There’s not half the files there used to be,
And there’s a milestone hanging over me
The system crashed so suddenly.

  I pushed something wrong
  What it was I could not say.
  Now all my data’s gone
  and I long for yesterday-ay-ay-ay.

Yesterday,
The need for back-ups seemed so far away.
I knew my data was all here to stay,
Now I believe in yesterday.

Poets of Matter

Ask any of the chaps, and they’ll tell you.

“Q?”, they’ll say, “Why, he’s a vigorous young buck, springing lightly from one adventure to the next!”

So you might be surprised to hear that, not only am I actually old enough to have a nephew who is himself a father, but that he’s also well established in his career as a design engineer, to the extent that he’s recently published a rather nice little book on the topic.  

If you’re thinking about engineering as a career, or a degree course, or an apprenticeship, then you may have some idea of the kind of exams you’ll need to pass and the things you’ll need to know.  But what might your life actually be like?    Are you basing your expectations simply on the splendid pictures of Isambard Kingdom Brunel standing beside enormous anchor chains?  Because if so, you might need a little bit of updating.

Poets of matter.

James talks about the inspirations and the frustrations, the hard work and the sense of achievement, the old skills and the new tools that might be associated with the noble pursuit of engineering in the modern age. It’s a great guide to what might lie ahead of you if you do decide to go down this path, and the mental attitudes that will help you prepare for it and get the most out of it.  I’m biased, of course, but I thought it was very nicely done.

Recommended for anybody you know currently contemplating their future careers.  

Go on, buy ’em a copy!

 

 

Train-ing data

I very seldom use the railways in the UK any more, though I did make two short one-way train journeys in 2023. The first was to collect our campervan from the dealer, and the second was when Rose, Tilly and I took our inflatable kayak from the little station at Bures one stop up the line to Sudbury, and then paddled back down the River Stour to where we’d left the car in the station car park.  That was fun.  They do have their uses for one-way journeys.

But I don’t think I went on a train at all in 2024. (Oh, actually, wait a sec… none in the UK: there were a couple of trips on the Athens metro.)   I do quite like trains as a theoretical concept, and use them when I’m in other parts of the world, but the reality here in the UK is that, unless you’re unfortunate enough to live in London, driving is generally much more comfortable, more reliable, usually quicker, and always much cheaper than going by rail, so there are very few circumstances when I’d choose to go by train.  Even the obvious advantage that you can read on the train is now significantly diminished by having Audible in my car.

And before anyone points out the green credentials of rail travel, it’s less clear-cut than you might think. This page suggests that even if you include all the CO2 used in manufacture, the carbon footprint of two people travelling in an EV will work out at 90g/person/mile; very similar to the 80g/person/mile of a standard-class UK train seat, and way better than a first-class seat.  If there are more than two of you in the car, you can feel especially virtuous, as well as saving lots of money. This UK government report suggests that EVs and trains have broadly the same emissions if there are only 1.6 people in the car.

There was a brief period in the past when I worked in London for a few weeks, but I quickly realised that life is not a rehearsal, you only go around once, and spending any significant part of one’s all-too-limited time on a commuter train was sheer madness!  But I’ve found that as long I only use the railways for unusual trips at off-peak periods, or on holidays, I can maintain a nostalgic fondness for them.  (And if you’re ever able to take all that money you save over the years by not going on trains and blow it all on one ticket on the Orient Express to Venice, I can definitely recommend the experience!)

All of which is a rather long introduction to the fact that I do still find this live train map from SignalBox to be rather pleasing!  You can sit comfortably at home, picture all those trains rushing in around the country, and feel some sympathy (or perhaps schadenfreude!) for those whose icons are not green.

Another AI cautionary tale

In one of my YouTube videos, I talk about how I’ve wired up my solar/battery system to ensure the energy in my home battery isn’t ever used to charge my car (which has a much bigger battery, so doing this doesn’t normally make sense), while still allowing the car to be charged using any excess solar power.

I had a query from somebody who was confused about how it worked, so I did my best to answer, and we went to and fro in what became a decent-length conversation.  He has a similar inverter to me, but had some fundamental misunderstandings about how it worked.  

At first, I assumed this was because he had different goals: he lives in another part of the world where there’s a lot more sun and a much less reliable electricity supply, for example.  But no, it turned out he wanted to do the same thing as me, but was convinced it wouldn’t work the way I had described it.

It turned out, in the end, that the source of his confusion was that he had asked four different LLMs (ChatGPT, Claude, Perplexity, and Grok) about how to configure the system, and they had all agreed that ‘battery power is never used to power loads on the “Grid” port’, which is actually incorrect.

What persuaded him, in the end, that my description was right, and that all four LLMs were wrong?

He read the manual.

W. Heath Robinson

We have some Heath Robinson cartoons which we still very much enjoy, but for which no longer have the wall space, and so have given them away.

I thought, though, that other Status-Q readers might enjoy them too. (Click for larger versions.)

Plucky Attempt To Rescue A Family Overtaken By The Tide

Some Occasions When A Gentleman Is Not Expected To Give Up His Seat To A Lady

A Surprise Packet For The Cat Burglar

Christmas Classics

The oral tradition has long been an important part of preserving human culture, and it is perhaps especially at this time of year that we’re conscious of works of music and literature that have been handed down through the ages.

While I was showering this morning, for example, I found myself singing a cheerful seasonal song which my brain had kindly preserved for me, almost intact, for more than half a century, but I just couldn’t remember the first line.  It was only as I was towelling myself down, that it came back to me.

Christmas, Christmas, in Smurfing Land

Anyone else grow up in the 70s?

Misplaced trust

This might be a little technical for some readers, but don’t worry, it’s not actually the technical detail that’s important…

On my home server, I run about half a dozen services that I need to access via a web browser, so they’re all behind a Caddy reverse proxy which connects me to the right one, depending on the name I use in my browser: ‘homeassistant’, ‘unifi’, ‘searxng’, ‘octoprint’ etc. (All of these names are aliases for the same machine.)

One of these services is Nextcloud, which has user accounts, and I was thinking it would be handy if I could use those accounts to authorise access to the other services. Can I allow someone to use my web search frontend only if they have an account on my Nextcloud server, for example?

I thought I’d try out an AI system to see if it could speed up this process, because they’re often good at this kind of thing – Google Gemini, in this case. And, to my delight, it gave me pages of detailed instructions.

It knew that Nextcloud supports the OpenID Connect system, told me how to set it up, and then how to use the oidc directive in the Caddy configuration file to connect the two, so that Caddy could ask Nextcloud whether the user should be allowed in. It gave me nice examples of oidc actually in use, and the parameters you’d need to configure when using it to talk to the Nextcloud instance.

“Great!”, I thought, and grabbed a coffee, went upstairs to my machine, and started typing code to try it out. And it was then that I discovered…

Caddy doesn’t actually have an oidc directive.

The Maritime Approximation

Spotted this nice xkcd item on Bluesky today.  It’s tempting to think it’s significant, but it is, of course, a coincidence.

(People who like this might also like this elderly post and its comments.)

Making ‘social’ social again?

Back in about 1996, I was attending a conference in San Francisco.  As we walked into the Moscone centre to register, we were all given not only the usual branded bag and bits of paper, but something much more exciting: a box containing what was to become my first true pocket-sized mobile device, the recently-released Palm Pilot.

Palmpilot professional cradle.

I don’t know whose idea it was to give these to everybody attending the conference, or how the finances worked, but it was a brilliant move.  Not only was it an exciting surprise, but we immediately had an application for it: the conference proceedings were available on it, and you could slip it into your back pocket; something you certainly couldn’t do with the paper equivalent.  And there was something more important, which I’ll come back to in a moment.

But for those less ancient than me, I should perhaps explain that what was brilliant about the Palm Pilot was the things it didn’t try to do.  It had been preceeded a couple of years before by the Apple Newton, for example, which was a lovely device, but just tried to do too much and was thus expensive, large and heavy on power.  The Palm guys realised that what people really wanted was just a cache, in their pocket, of the stuff they had on their PC.  (Laptops were heavy, and expensive, with a short battery life, and you had to wait for Windows to boot up before you could check someone’s address.  You might have one in your hotel room, but you probably wouldn’t carry it around.)

With the Palm devices, though, you would create and manage most of the content on your computer, which had a proper keyboard and screen.  When you got back to your desk, you’d plug the device into its cradle, press the sync button, and any changes would zip to and fro, after which you could unplug it and put it back in your pocket.  If you had migrated away from paper diaries and address books to keeping data on your PC, this allowed you to have that information back in your pocket again.

But you did have to plug it in to its cradle periodically, where it could talk to the PC using an RS-232 serial port. This was before 802.11 (the standard which, several years later, would become known as ‘WiFi’) and the Palm Pilot had no other networking.  Well, almost none.

And that was, I think, really important.

You see, the lack of WiFi meant that it couldn’t distract you all the time with incoming messages.  You could read email on it, but only the email that had been received on your PC when you last plugged the two together.  So you would actually listen to what was being said at the conference: something almost unheard of these days!  

But the device did have one further trick up its sleeve: it had infrared capabilites.  It could exchange information with other Palm Pilots (and later with some other devices), using the same kind of line-of-sight connection that TV remotes used.  That meant that for me to get your address and you to get mine, we needed actually to have met and collaborated in the exchange. I could send you my contact details across a conference table or while having a drink at a bar, in much the same way I could give you a business card, but it was so much more convenient because there was no need to transcribe the information afterwards if you wanted it in digital form.

This did require both of us to have Palm Pilots, of course, so what better way to kick this off than to make sure that, at a few key tech conferences, almost everybody you bumped into, for several days, would have one in their pocket?

~

Back in the early days of LinkedIn, there was a similar culture of only linking to people you actually knew; in fact, not only knew, but endorsed.  I joined the beta release back in early 2004, and to this day I normally only link to people I’ve at least actually met, though in more recent years I’ve extended that to include ‘met on a video call’ or ‘had really quite a long phone call with’.  

Nowadays, I do sometimes wonder why I’m still on LinkedIn, since it’s the source of more spam in my inbox than anything else.  I’m not really out hunting for jobs. I’ve always joked — and it’s almost true — that I’ve never got any job I applied for and I’ve never applied for any job I got.  And I’m not recruiting people either at present.    LinkedIn is very much a work-related system, but having dropped in to the website just now for the first time in ages, I must confess that there was more interesting content on there than I expected, perhaps because it is linked to people I actually know in real life.

(Increasingly, social networks are things I visit in the same way I might visit parties; drop in for a while, see what the atmosphere is like, leave if it doesn’t appeal, but maybe visit again a few weeks later.  I’ve just deleted the Twitter app from all my devices because I realised I could still drop in there using the web if wanted, but I didn’t need its content, or its notifications, delivered to my pocket.)

~

Anyway, I was thinking about all of this as I read Ev Williams’ article, Making “Social” Social Again, in which he announces the launch of Mozi.  This is meant to be a social network to help you with your actual social life (and not a ‘social media’ platform).  It’s about getting and maintaining up-to-date contact information for your friends, and knowing about their travels so you could meet up with them.

I don’t know whether it’ll succeed.  There’s always the problem of bootstrapping a network when you can’t, say, give several hundred people a sexy new device that they’ll all be carrying around in their pockets for a few days.  But it would be good to have something that is primarily about contacts rather than content, and yet isn’t primarily about work.

And he reminded me about Plaxo:

As I was making my birthday list, another, more practical, thing struck me: I had no go-to source for knowing who I knew. No online social network reflected my real-life relationships. The closest thing, by far, was the contacts app on my phone.

And, boy, was that a mess. I’m guessing, yours is too.

Why?

Twenty years ago, there was an internet company called Plaxo. There have been others like it, but Plaxo was the first big online address book. I remember thinking it was one of those simple but profound twists on an old product that was now possible because of the internet, i.e.: Why do I have to keep details up to date for hundreds of people in my address book? Now that we have the internet, you can update your address in my address book, and I only have to keep mine updated.

It was an obvious idea. And here we are, 20+ years later, with address books full of partial, duplicate, and outdated information.

Anyone encountering the same problem while writing Christmas cards?

The problem with Plaxo was that it required you to upload your address book to their servers, and I always felt uncomfortable with that.  When someone gives you their details, their is an element of trust involved.  They might not want you to broadcast their home address to the world, and they’re kind of assuming you won’t.

But nowadays, most people do this anyway, they just often don’t know that they’re doing it.  It’s one of the reasons that, for a long time, I didn’t want to have anything to do with WhatsApp, Facebook and Instagram.  But I abandoned my principles last year when I realised that all those friends I was trying to protect were already using those services and so all of their contact information was there anyway. And, because of them, so was mine.  GDPR, eat your heart out!

Signal, in contrast, has a much better system which allows them to discover whether your contacts are on Signal without actually uploading your address book.  In a world where we have these kind of techniques, and end-to-end encryption, and protocols for sending contact information, why is it that I can’t give you the permission to update your entry in my address book without my address book being stored on someone else’s servers?

I don’t know if Mozi will enable that.  If they do, then I’ll believe we’ve made some progress from last millennium, when I could send you my current information with a couple of clicks and a beam of infrared.

 

 

The FreshWash Clip – Every home should have one!

This afternoon I went into our little utility room, made some measurements, and created this beautiful work of art on my iPad:

 

Rough sketch of clip

I then went upstairs and opened up my CAD program, where I was able to turn it into this:

Flat sketch of clip

And extrude it into three dimensions, so it looked like this:

whence I could 3D-print it, to get this:

Now, as most of you stand amazed, there may yet be some readers for whom its use isn’t immediately obvious, so I should explain.  

If, like us, you don’t have kids, and therefore don’t need your washing machine to be running 24×7, the seals and the inside of the drum stay fresher and nicer if you can prop the door open and let them dry between washes.

And so I created the FreshWash Clip™️.  

It works perfectly, and I get a deep, if childish, satisfaction from it.  The hole on the top makes a bit of a handle so it’s easier to clip on and off, and can also be used to hang it on a hook on the wall.

This particular model is sized precisely for our elderly and out-of-production model of John Lewis washing machine, so I doubt I’ll be producing it en masse, but no doubt Chinese entrepreneurs will seize the opportunity to prove a whole range of different sizes and colours, and on Etsy you’ll soon find artisanal variants lovingly crafted from bamboo.

And as FreshWash Clip mania takes hold, and no home can be considered complete without one, please remember that you saw it here first!

© Copyright Quentin Stafford-Fraser