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GNSS
Episode 5115th November 2022 • Tech Talk with Amit & Rinat • Amit Sarkar & Rinat Malik
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Every day we use some kind of navigation to go from one place to another. We also use it to track our fitness routine like running or cycling or hiking. We sometimes use it where there are no roads or waymarkers. And we use it even without a mobile network. Have you ever thought about how this navigation works? Why do we need to activate location services on our mobile phone to receive our accurate position?

In this week's talk, Amit and Rinat talk about GNSS, the different systems in the world, how it works, and a lot more!

Transcripts

Rinat Malik 0:00

Hi, everyone. Welcome to another episode of Tech Talk. With us today we have Amit and myself. We are going to talk about GNSS despite be a bit of an unfamiliar topic to a lot of you, but part of it is very simple, very familiar. GNSS stands for Global Navigation Satellite System. And a lot of you would probably be familiar with a subset of this topic, which is GPS, which we're going to talk a lot about in this topic. But yeah, the parent topic, the overall bigger idea is GNSS. And it's an interesting topic very technical. And quite excited to talk about it today. Amit, thank you for coming up with this topic. I don't really know a lot but I'm looking forward to learning from you today. So yeah, let's, let's start talking about it. What's GNSS?

Amit Sarkar:

So global navigation satellite system is GNSS. And but first of all, thank you so much for the introduction Rinat. I wanted to touch base on this topic is because we are all familiar with GPS and we are all using it constantly in our daily lives for navigation, for checking which other closes restaurants near us, etc, etc, based on our location. So we are constantly using it. But do we really understand how the technology works and what are the implications and what are the other systems? And why GNSS what is GPS? And what are the other satellite systems? So that's why he just wanted to touch base on this topic to get people familiarised with type of technology that is quite ubiquitous. But yeah, I mean, a lot of people don't know actually about it a lot.

Rinat Malik:

Yeah. And when you talk about navigation system, you I mean, you know, we always come back to this about privacy and security and things like that and GPS or GNSS would have a like a large part talking about how you're being tracked. Right. That's, a really important part of the topic itself. But yeah, I mean, there are so many sort of areas where GNSS on GPS can be explored into and it's very interesting and complex topic because you know, the technology behind it is so interesting, and it could date back all the way back to Newton's theory of gravity. And, you know, from there how we found that that doesn't work and Einstein's theory prevails because of the minute changes in calculation. So these are all very interesting, and hopefully you guys could enjoy this talk with us. And as we explore the topic further.

Amit Sarkar:

Yeah, so, so let me first, like, make it a bit clearer that it has got nothing to do with privacy. The reason being, we're just receiving a signal on a radio device that said it just as simple as that we're not sending anything out. All the calculation is done on your phone on your device actually.

Rinat Malik:

Does Google not Track your location? does it not really…

Amit Sarkar:

Google tracks the location, but the satellite the system itself doesn't track it. You use a system. The phone itself will track your location that track all the voice they will track all the search history. Yes, it does. But we are not talking about the phone we are talking about the system itself. Let's start from the beginning Global Navigation Satellite System. Global it means it covers the whole planet. Navigation means you are using some system to navigate around the planet to go from one place to another. Navigation means to go from one place to another to Overland oversee over mountains etc. And the satellite system is basically you're using the satellite, then not a single satellite but a system of satellites multiple satellites 2030 satellites in that system. And together it's called a navigation satellites Global Navigation Satellite System. And there are different countries who are who have made their own systems. And what we call them is a constellation a constellation from what we read when we were young, is basically nothing but a group of stars. A group of stars together it's called constellation. Similarly, a group of satellites together can be called a constellation. Now if you look back systems which were there before GPS came, we had maps someone had to draw the maps and then we used to look at the sun and then we used to decide where we are. But if it is the night use look at the stars. We used to say this is the North Pole, sorry, the North Star and based on the North Star, if you're in the northern hemisphere, if you're in the southern hemisphere, you have a different star. So if you're in the southern hemisphere, you have the Southern Star and based on the star you would be able to navigate Okay, so that there is that constellation there is this constellation and based on where you are or what you can see, you can then maybe to a certain extent, figure out where you are in the world, or how far you are from where you started. So that was how we navigated. Okay, so we look at the tree we look at the star then we move then we look at another tree, another star, etc, etc. And similarly over the period of time we looked at how the sun moves, so we have a sundial so we know how, what's the time of the day, etc. So looking at the stars, you could tell the time and you could also navigate. Similarly, with a GPS system, you are able to navigate, as well as know where you are in the world and then figure out what time is it because based on the location you can figure out what time is it on you're at a particular location. So GPS, GPS was started by us and it is still operated by us. So us owns the satellite system. They launch the new satellites. Each satellite lasts for about 10 years. And once a satellite gets old they renew it by sending a new satellite. Okay, in that constellation. There are about 24 to 30 satellites. Each satellite takes about 12 hours or you can say the complete two rounds. of planet Earth in 24 hours. Okay, so two rounds a planet Earth in 24 hours. So that's the satellite system. Okay, that is what the satellite is doing. Now, in order to control the satellite, you need a ground station you send a signal. Okay, steer here. Stay in orbit. Okay, what's the time on your, on your sat on the satellite? Okay, this is the time here on Earth. So can we just sync the time, like we sync with atomic clocks, or we sync with different servers? So we sync the time we look at whether they are at the right orbit, do we have to give them enough trust so that they stay in orbit? Then is there any software maintenance needed, etc. So there is a ground system taking care of that? Those satellite systems

Rinat Malik:

So sorry to interrupt. So GPS, as far as I know, it stands for Global Positioning System, right?

Amit Sarkar:

Yes.

Rinat Malik:

So a lot of the times what happens is whenever I hear an acronym, here, the fool for me kind of gives me a bit of sense and so I thought that global positioning system is like a global solution by all the different countries they all collaborated, but now you're saying GPS is just U.S. So how does this and what is global positioning system even mean like …?

Amit Sarkar:

So basically, the system was launched by U.S. When it was launched, it was launched by the US military for their purposes, and it was called NAVSTAR. When it became public, when it was given out to the public, that's when it became actually GPS Global Positioning System. Okay. But it is just one constellation maintained by a country. Okay, so those are satellites. Someone has to send the satellite remember that someone has to send the satellite someone has to maintain it on course, then of once the life of the satellite is over, they have to send another satellite and someone has just sent it on a rocket, someone has to buy space on a rocket ship to launch those satellites. So someone has to do all that work. Now there is no collaboration right now in even in International Space Station, which is majority U.S. it is still coordinated by other countries. But still it is ISS is all of U.S. baby. It is still an international cooperation, but it's more of a US baby. So similarly, GPS is a US baby. So GPS is maintained by U.S. and it was the phone system and now there are other systems in the world, which can be used for navigation. Now, if you go to GSM Arena, good. Yeah.

Rinat Malik:

So so when I Right now we're both in UK, right? And we're getting our positions in Google Maps or wherever we are using GPS as far as I know it was GPS, but is it not called GPS. So, so another yard is like Middle East or why am I using somebody else which is called somebody else?

Amit Sarkar:

So let's cover the basics first then I'll explain. So we have one system 30 satellites. Around about 30 satellites, they take the complete two cycles around the planet. And the satellite is basically sending radio signal. Why radio because radio can travel long distances. Wi Fi doesn't travel outside our house. So you need a signal stronger than Wi Fi, maybe a radio signal but FM or AM? you don't know. Right? So there is a basically a radio signal that's coming and our smartphones are basically nothing but a radio device. Right? We receive a signal from a cell phone tower. That's a radio signal. It could be it could be maybe not at the radio frequency but at some other frequencies. But it's still effectively electromagnetic wave that's coming to your phone. Let's say it's a radio signal because voice is there etc. And we have to carry the voice over long distance. Sometimes what happens is it's part of it is travelling digitally and the part of the parties like analogue, but most of it is still radio signal. This satellite is sending a signal, the phone is receiving it and there is a ground station that's controlling the whole system. So there are three systems involved a satellite, ground station and the receiver. The receiver could be a smartphone. It could be a smartwatch, it could be any GPS device, okay, we call it a GPS device. Now, how does it How does your phone know where you are? The satellite is not telling me where I am I receive a signal okay, then I calculate wherever I received the signal, how long has it taken, then I receive another signal. Then based on that I can say okay, this signal is coming from this place and it has taken this much time and then I take a third signal, so forth. So I take about three signals to identify my 3d space where I am on a two dimensional level without any alternative.

Rinat Malik:

Yeah, so this is what I've heard about like you triangulate from three different cell phone towers that you know, once your time delayed, you could kind of identify

Amit Sarkar:

But the cell phone tower has a long range. So if you're inside the tower and you can travel from your house to another house, maybe another two blocks, the range is quite good right. But if you want pinpoint accuracy, like I am here, not three blocks away, that I need to have a better triangulation system, right? Far better compared to a cell phone tower. So for that, and when the smartwatch or smartphone is calculating the calculate the exact location. They don't create a circle or they don't pinpoint like, they don't draw a line. Or they don't draw. What they draw is a sphere in this sphere. I could be anywhere in this 3d space. I could be anywhere. Then they take another sphere that is in 3d space.

Rinat Malik:

Right, I'm just thinking like, because you've said radiofrequency right so now the wave has it's like it's really large wave, right? The wavelength is probably like 10 metres or something.

Amit Sarkar:

I don't know the exact wavelength. I think it is

Rinat Malik:

Is it because of the wavelength that the pinpointing is not possible because…

Amit Sarkar:

No, it's simple mathematics. So let's say I tell you are 300 metres sorry, 300 kilometres from Trafalgar Square. Okay. 300 kilometres of Trafalgar Square could be anywhere. Right? Now I say you are 300 kilometres from Trafalgar Square. But you are 200 kilometres from Brighton. Brighton Beach, no region, you still don't know a point you know and intersecting a region. Then you say I'm 300 kilometres from Trafalgar Square 200 kilometres from Brighton Beach and I'm 100 kilometres from Dover Beach. So now that's triangulation, right. You have three different points. And now you can say which is the intersecting area and in that small right but in that intersecting area, there will be still two or three points where you could be a circle something right. So it will have two dots. So you could be there or there. If you if you draw three circles together, and then you see where the points in where the circles intersect, there will be two points of intersection. Okay? so that's that's the triangulation, but instead of imagining it as a circle or a line, imagine a 3d space. So you have a 3d space with the radius from Brighton 3d. space with radius from Trafalgar Square in 3d space with radius from Dover. And in that 3d space, you are somewhere in that region, get a fourth satellite, and now you can tell exactly where you are. And you can also tell how high you are the elevation.

Rinat Malik:

But, but, I mean, how is the height determined because this is in a geometric space, you're kind of later fourth tower sort of pinpointed more your location but how ?

Amit Sarkar

Exactly, but pinpoint is…. So the location, location is for the device, right? And the device is at a particular height. Say you're in Mount Everest, giving an example. So from Mount Everest, the signal will take less time specially from the sky, it will take less time to come to you. So you can you can decide the horizontal elevation and the vertical elevation right? where you are. So based on based on where you are located.

Rinat Malik:

Is it because of the depending on the time it takes for the signal to cover?

Amit Sarkar:

Yes, that is

Rinat Malik:

as very intricate. That's really interesting. Yeah,

Amit Sarkar:

So it's not just like the signal you're receiving the signal. How much time is that it has taken for you to receive that signal from that particular satellite, so all that is calculated. And these satellites are sending signals at particular frequencies or range of frequencies and each system so we talked about GPS and there are other cons, star constant satellite constellations provided by other countries in the world, and they use their own system, so they must be using a different frequency because you don't want to send the same signal at the same frequency. You want to use different frequencies so you don't jam so you don't jam, maybe aircraft transmission. So l aircraft is travelling and they are sending the ATC tower or they're talking to the ATC tower at a particular frequency. You have cell phone frequencies. You have so many other frequencies. So you need to have a bandwidth in which you will send only the GPS signals and no one else is going to use it for anything else. And then you need to say my country my constellation of satellites will sell set the GPS signals only in this frequency but your satellite your system will send it in that frequency. So from one country to another, there are different regulations right? So you cannot like the cellphone frequencies that you use say in UK are different from maybe cellphone frequencies that we use in India or in U.S.

Rinat Malik:

Is that how it is? because I didn't realize

Amit Sarkar:

pretty sure, I'm pretty sure. I mean, they might have a limitation like okay if you because that's why you need a SIM card to register yourself on that. particular network.

Rinat Malik:

Right now, I remember like, I think more than 10 years ago, but there was GSM 900. And

Amit Sarkar:

GSM 900 there is minor debt. Yeah. So I think it's the same set of frequencies. But you have to use a particular network in order to access those frequencies. So yes, you're right. You're using the same frequencies everywhere. But you have to get authenticated to use that network in that particular region.

Rinat Malik:

This is what also confuses me because you know, what you're saying is GPS is only in U.S. So in Europe, we have not….

Amit Sarkar:

No, no…globally, because earth is, if you take a circle around the planet earth, it's not like you're just going above U.S.

Rinat Malik:

You said, That's owned by U.S. but

Amit Sarkar:

Owned by U.S. What that means is if you look at Facebook, Facebook is a US company right? It’s like that. Facebook is used globally, but it's a US company, it's registered in the US. Right? If they operate in Europe, they have to have a separate companies have separate taxation, etc. But essentially it's a US based company. But it's used by everyone in the world. So GPS is a US based system used by everyone in the world. Okay? The other systems that are there is GLONASS. This is owned by Russia. Global Navigation, satellite system, glow. For global NASS navigation SS satellite system, okay. For Europe, it is called Galileo. Okay? then for China there is Beidou spelling is B E I D O U. Beidou China. Okay?

Rinat Malik:

So the same as Baidu

Amit Sarkar:

Which is a search engine, which is the famous search engine, which is the alternative to Google in China, right? So China has their own constellation. Then you have India, India's called something called as NAVIC. Navigation, Indian Constellation, Navigation, Indian Constellation. Okay. So that's India, and then there is Japan. Q Z S S, quasi Zenith Satellite System, Q Z S S. Okay. So these are the major satellite systems in the world today. Okay. Now, when you buy a smartphone, if you look at the specs, say you go to a website called GSM Arena, and you look at the specs for a particular phone say iPhone 10 or iPhone, say the recent iPhone 14 Pro, you just look at the specs for that. And if you scroll down, at the bottom, you will see G navigation systems and there will be GPS, GLONASS, etc, etc. So basically what it means is it is not just using one singular system to tell you where you are, and what's your elevation, how fast you are moving, but it's using multiple satellite systems to tell exactly where you are. And but why is it needed? Can you answer why is it needed? Why are these different satellite systems?

Rinat Malik:

triangulating it's triangulating from farther away or by

Amit Sarkar:

but GPS system could do everything Why did Europe or in Russia build their own?

Rinat Malik:

Travelling then I am also covered or is it because the GPS also covers the whole world Right?

Amit Sarkar:

Exactly. Rinat Tell me why do we need so many systems?

Rinat Malik:

So the only other thing I only the reason I could think of is because if it would give you more accuracy if you know if you had

Amit Sarkar:

I think from a tech I don't think technology

Rinat Malik:

yeah if I if I kind of zoom out a little bit international relationships or whatever. I think each country will do it for their own safety.

Amit Sarkar:

Tomorrow, U.S. blocks access of GPS to Russia. How will people navigate in Russia? So there is a there is a war happening now in Ukraine Russia has invaded Ukraine and Western countries have put a lot of sanction. And I'm guessing one of the sanctions would be you're not going to use a GPS satellites.

Rinat Malik:

Yeah, that hasn't happened yet. I think but yeah, it could.

Amit Sarkar:

It could, right? It's a it's a part of the warfare. I mean, I don't know how you block it. Like do you block it when it goes over? Russia? How do you do it? I don't know. But it is one way to block access to a navigation system. Right? Of course, also jam a signal so you're receiving a signal you can jam that signal from that particular so you need backups. In case GPS fails, the world has no backup. So every country vote for itself thought for its own benefit and they have come up with their own system. So Europe has GLONASS. It doesn't mean that you are using just GPS you are actually using all the systems which are supported by a smartphone, which you are not aware of which you will be only aware when you actually looking at the specs. And that's where I got this idea of let's talk about this topic because many people may not be aware that we are using multiple navigation systems on our store

Rinat Malik:

Even if I am just in one country, I'm still using all of these?

Amit Sarkar:

All the systems all the systems, if the satellite is going up, have you so imagine that there are 30 satellites have a GPS and there is maybe 30 satellites, Galileo, and if you're in India, then you have NAVIC so it has about 20 or 30 satellites and they are there. But at any given point in time you will not have all the satellites over you. So suppose the 30 satellites orbiting around planet Earth from GPS, not all the 30 satellites will be over India when you're there. Maybe one or two maybe three. But if you want more accuracy, you might use some other systems. I use system from India. I'll use system from Europe. I'll use system from Russia and with those with all that information I can pinpoint exactly where you are under which tree you are. Right. So in order to increase the accuracy, the systems there are so many systems so just leverage on those things. Okay? So, that is that is the whole constellation and that is the whole idea of why we have why there is why we selected this topic of global navigation satellite system because there are multiple systems and GPS is the most popular. It's the first so it has stuck. So now there is a search engine we say Google it. Google is not the only search engine there is Bing there is Baidu there is many others. Exactly. So but we it's like okay, just Google it. Just like Earth we have GPS, but GPS is just one system of many

Rinat Malik:

Right yeah.

Amit Sarkar:

But GPS what is it used for? I mean, we know position location, but exactly what are the what are the main things so what is your position or location where you are? Others navigation? Point A to Point B so you use Google Maps or you use any mapping software and you want to go from one place to another so you use navigation. So it looks at where you are located. And from there, where do you have to go and based on that it tracks your chart that tracks whether you're on track or not. If you go out on the road, or you miss a turn then it out based on the location. So it's tracking navigation. Then

Rinat Malik:

Ami you start talking about this and then you realise how much calculation is actually going on in all of your mundane tasks that you do. So amazing.

Amit Sarkar:

Right and it's happening in the palm of your hand.

Rinat Malik:

Yeah, Also the expertise required to make all of these happen. I mean, it's just it's just phenomenal. I mean, but the thing is there's so many smart people are working to make all of this possible but they all have specific expertise. The person who is like, you know, really expert on GPS system or maybe doing not, maybe you can't be an expert on the whole GPS. You can only be an expert on that part of it to do one type of calculation from satellite to your phone or whatever. And then all of these different experts collaborated together to make something that is that is so beneficial to the mass public exactly, which is quite interesting to me.

Amit Sarkar:

I mean, just like the internet, right, it was called the dominant. Right? And the internet because it was open to the public. So similarly, this was NAVSTAR when it was open to the public, for the benefit of everyone, right? But because the military saw that, okay, this can be actually used for so many other people and so, so many other benefits. So we talked about location, we talked about navigation, what are the other things we can use it for? Tracking. So, if someone gets lost, you can track that person where they are. tracked? Yeah, farm animals, where they're going.

Rinat Malik:

Oh, yes, yes. Yeah. I mean, anything that you want to track which needs a higher range than Bluetooth, yes, that's that as long as you can. Right. I mean, but I, one of the things I always wonder, right. I mean, I see some YouTube videos where they create like a makeshift balloon to go to space with a camera and then drops down after you know, after it reaches a certain height you can't go on anymore because the pendulum bursts or whatever. And they kind of drops down but by the time it drops down, it's like farther away from where it lifted off from. So, How does the person find that?

Amit Sarkar:

So, tracking beacon so that is constantly being sent and you're just tracking that?

Rinat Malik:

And the other thing is, you know, location in Mars, you know, when we sent the I even forgot the name, the rover or

Amit Sarkar:

Pathfinder perseverance.

Rinat Malik:

Yeah. So how would we know the look is how are we communicating with the that’s not GPS, of course,

Amit Sarkar:

That is not GPS. SO they have other navigation system, and I'm pretty sure there is a so before you send a rover on Mars, you have to first send a satellite that can orbit the planet. So you track the weather, you track the you, you map the whole thing. So the next step from tracking is mapping. So you have to first you have to then start mapping and how you map is you take the phone and you start moving around with the phone. So then you can figure out okay, where are the roads? Okay, how much is the height and you can then create a map just based on altitude and where you are located which are the roads which are the rivers how fast you're moving, if you're on a flight, et cetera, et cetera, right. So that we can do mapping. So that's another way and the last is time. You keep track of the time based on the location based on the where we are in the orbit. Right?

Rinat Malik:

Right. Okay.

Amit Sarkar:

Because time is arbitrary, right? Time is arbitrary. I mean, we say that okay, time is part of the universe, but it's not measured against something. What? reference point, but what is the original reference point? It's like the question of God, is that really what is original God? So it's something like that. What is the original reference point? There is no original reference point. Everything is referenced against something.

Rinat Malik:

Yes, yes. That is that is very interesting, to be honest. I mean, I know we're kind of off topic. Off topic a bit. Yeah. Right. Yeah. Where are you talking about length? Yeah, there is a reference point even which you know, which, against which the metre is defined or centimetre

Amit Sarkar:

But length, you can see time you see,

Rinat Malik:

That's what I really like, makes me really excited. To think about is because time is the reference point is also a reference point itself is arbitrary. You're just deciding this is what a second is

Amit Sarkar:

Exactly. And the second is different based on the gravitation force. So theory of relativity says that the time on Earth and the time on Mars will be different, or the time at the centre of the Earth and the time and top of Mount Everest will be different. time on an aircraft that is travelling at the speed at very high speed will be different than people who are actually on the ground. Time of the satellite. will be different people are on your smartwatch.

Rinat Malik:

Absolutely. And people who are frequent fliers would age differently. I mean, you could be a very decimal point. Second, smaller higher but still

Amit Sarkar:

There is a difference. So when the grounds had when the ground stations are controlled, controlling all the satellites, even if there is a one second out of sync, then the satellite could be like hundreds of kilometres away off orbit. So you have to make sure that they are always constantly in sync with the time so that you can track where they are exactly. Otherwise you can lose a satellite.

Rinat Malik:

Yeah, this is this is actually related to what I was saying in the beginning. of our talk that this is how we kind of proved that Einstein's theory of gravitational theory is more correct than Newton’s. Be more or less correct.

Amit Sarkar:

I think he just added a dimension of gravity. So Newton added the dimension of length and time, and Einstein added the dimension of gravity to the whole equation. So Newton said that everything is absolute Einstein said everything is relative.

Rinat Malik:

Yeah, I think I mean in terms of gravitational force, though, I think basically Newton was saying is to two masses are attracted to each other. But Einstein was saying that we're all in this fabric of space time. And then we bent the space time and that's how the attraction calculation is. Different.

Amit Sarkar:

Yes. So the gravity that is actually not gravity. It is the bending of space time. So it is like you're going on a piece of paper, but if there is a ball, you start sinking, you start towards that ball. So similarly I'm going towards Earth. From sun, because I'm closer to earth. So closer to the what do you say the curve, the curve that is created, and if you go towards sun, it is more so I fall more quicker. The moment I enter sun's gravity

Rinat Malik:

Yes, absolutely. Yeah.

Amit Sarkar:

But if I

Rinat Malik:

There are really good graphics around,

Amit Sarkar:

Really good graphics, but those are all two dimension, you have to now think about three dimensions because that same thing is applied on top as well. It's not like it's just you're going down as well. Right? The space is went around it, not just in one dimension.

Rinat Malik:

That's very interesting to think about. Because for some reason, we're all like, I don't know. I mean, the initial instinct is to just think about 2d, but we are 3d people. I mean, when we're very much capable of imagining it the way we were taught in our education system is to make it easier for us to understand they're probably showed us 2D and then took us to 3D but I think we just you know, got familiar with 2D so much. That probably imagining something and that's a that's probably I don't know whether it's a good thing or a bad thing. But yeah, I mean, we have to kind of tell ourselves that we are in a 3d world and imagine, you know, all the physics around you is happening in 3d.

Amit Sarkar:

So if you think of a wormhole, what how would a wormhole look like in space in three dimensional space? Will it be a hole?

Rinat Malik:

It'd be a tube, right?

Amit Sarkar:

It could be a tube but how to how do you put a tube in space?

Rinat Malik:

Yeah, no, I didn't know. I don’t have the answer

Amit Sarkar:

So yeah, so intercell at the movie, they tackled this concept, right? The whole will be a sphere. Another dimension, but so just moving on from the what you said is yes, we by default, we assume everything is we assume everything into dimension, but we are actually three dimensional beings. So we need to start imagining in that direction. So how would 3d space when it's bent look like? we can't draw it right? We can't draw it. We can't create a week. Maybe we can create a video out of it. Maybe I'll share a video if there is someone on something on YouTube. But yeah, so that's about gravity. But let's come back to the navigation system. We have explored the different types of navigation system we have explored there are three main components. One is the satellite system sending the signal one is the controls area which controls the satellite to stay in orbit to maintain it to make sure that it's everything is correct. And then a receiver which could be your smartphone, which could be a smartwatch, which could be a proper GPS device. And the bigger the sensor, the better the signal accuracy. It's as simple as that. The bigger sensor of a camera, the more the better quality of the images. So similarly, if the bigger the sensor, the more information you can capture and you can exactly tell where you are. Okay. So it's important, but of course, now, the other any limitations to the system. Of course, there are limitations because these systems have been They are there but they don't know they can't differentiate between land and ocean. Right? So suppose

Amit Sarkar:

you are navigating and it shows Okay, there is a road going, going, going going and now you have to go to an island there is a straight line to go through a bridge, but now it takes you to the river. And there have been cases where actually someone has fallen into a river because the navigation took it there. Then

Rinat Malik:

This is in the early stage though right? when

;:

Early Stages nobody even now systems are getting better. But yes, it has happened. Someone has gone up a mountain and they're not able to go up or down. So those things can happen with the navigation system. And even now, I mean, when I try to ride a bicycle, it takes me somewhere like it's totally where there is no road I can't even ride a bicycle there. Of course you can walk over those areas, but it takes me to those locations where a cycle can't go. So those GPS systems are not that it will not tell you how the land is it will just tell you your location. So you need to think about that as well. It has got a limitation. It will not tell you the geography of the land. It will tell you where you are. If you're in the sea, it will know you are in the sea but you will not be able to tell that okay you are in the sea.

Rinat Malik:

Yes it is in your cell phone it cross references with previous data that Google Maps already knows which one is returned. And what is water. Exact. So that's how it …

Amit Sarkar:

So you use how Google Street View or mapping must have done satellite images and then people moving on that so then you can figure out which are roads which are not roads, you can maybe do you can create an algorithm where you can say okay, these are roads these are

Rinat Malik:

That’s another interesting part where how Google understand whether it's traffic or not because I saw another video I knew it before. But then this guy in the YouTube video where he actually put it in practice. I think it was in Norway or Denmark some European countries where he got all of his friends for actual mobile phones in a in a trolley. Like there's like 50 mobile phones and then he was walking around in a very quiet room when there is no traffic at all. But at that time check in Google Maps. It was like read like fully, you know, full traffic in that road because what Google does is Google takes Google doesn't know whether there is traffic or not whether this traffic jam, you know, people have to wait there's just no there's no GPS location of the mobile phones and if the phones are not moving in a straight then it kind of calculates that as

Amit Sarkar:

Exactly that's how they know that is a traffic jam. Because if there is so many people going in a particular direction, and Google knows that it's a road from the maps. And if people are not moving and the speed is slow, based on the GPS location, then it can connect everything together. And then say you're in a traffic

Rinat Malik:

Experiment was so cool. I've thought about doing this myself, but I couldn't I couldn't gather

Rinat Malik:

Yeah, I mean, if you just literally get 50 People walking the same direction but very slowly on a street. It will come up as a

Amit Sarkar:

System. So GPS system because it's a radio signal it can be jammed, you can block it. You can turn signals, right do you how do you block signals? Do you have some reflectors or you send some opposite signal etc, etc. So you can always jam it. And you know, they're a document a rotation, like okay, this signal is being sent at this frequency so you can monitor those frequencies. I mean, of course there is no information there it just position of a satellite and what will you do with the position of a satellite from Earth? You can't do much you can't remote control a satellite from Earth.

Rinat Malik:

Yeah, but I feel like if we within our audience, if we have like an avid telescope, person who looks at the stars and things in the sky. They might be quite interested in that you could calculate where a satellite is from

Amit Sarkar:

Yes, There are Apps and then apps can

Rinat Malik:

Point your telescope at it. And then you can see and I saw a video recently where the person was waiting, I think for a long time to see a satellite against the moon. So you know it would you know, they pointed it to the moon. But you know, a satellite would go through go past in between and that was that was actually a very cool video to watch as well.

Amit Sarkar:

I would I would love to watch that it would give a nice light trail across the moon. That'd be nice. So I actually, I actually use an app to track the International Space Station and when I knew that International Space Station was going above me, I actually saw it with my naked eyes because International Space Station is not very far. from us. It's like a few think it's about 400 kilometres. I can't remember exactly, but it's the closest it is closer to us.

Rinat Malik:

That’s sound like very close to Everest.

Amit Sarkar:

Yeah. So, so you can actually see it moving really fast with a very bright light with naked eyes, no sattelite needed. It is one of the so there are trackers which tell you like okay, when is passing over you? So, it's so cool. Like, you can do all these things. But imagine with these technologies, a smartphone has made us so dependent on it like we cannot travel without our smartphone. We don't know what to do. If we go to the forest, like how do we navigate ourselves?

Rinat Malik:

Exactly. More interesting even especially more interested now after you know learning all of this from you today. Is that how much calculation is happening in the background? Right I mean, you think Oh Why is my phone slow and but you know, it's just churning away mathematics behind in the background. So, but now it's due to should be fast enough.

Amit Sarkar:

I mean, we should also appreciate the computing power that has happened in the amount of space has in the physical space. So earlier, the computers used to fill up a room they used to be giant, okay, They use to fill up a room. Now they sit in the palm of our hand. They're that small, and they can calculate much more than what was calculated maybe in the computer that was sent to the moon.

Rinat Malik:

Yeah, yeah, absolutely.

Amit Sarkar:

So the computing power has become what do you say the computing power has become very, a lot. Computer computing power of computers has improved quite a lot and the size of the computers has reduced or the processor and because of that, we are able to enable all these technologies. We are moving further ahead. Now we are going to have AI processor on our chip someday that is going to just create a random AI or whatever and that will be the next step. So with so much compute power, you can do so many things.

Rinat Malik:

Yeah, absolutely. I am looking forward to what the future holds. Unfortunately, I won't be here forever. But yeah, but next 34 years. So we will be seeing that and of how things change. I mean, the way things are changing now are like in Mega speed. I mean, you know 100 years ago, then there were innovations but not at the speed that we're at. We're experiencing right now. Right? I mean, you know, cell phones have gotten like from a break to, you know, tiny ones. Handheld and foldable phones can do so much more. Right. Yeah, and all the different things where innovation is happening right now in AI and then in med tech in edtech. is all in all of these different technologies being worked on I'm quite excited for the future and hopefully our audience are too and hopefully you guys have enjoyed our talk about GNSS which is a parent topic of GPS. Today with us, please do let us know if you guys have any suggestion or feedback around what we talked about or we could talk about in future. If any of you guys have a particular expertise or not just want to reach out to us to talk about anything. do reach out our contact details and everything is within the description. In which platform you're listening to us at pig speaking of platforms, we are available in YouTube and all the major podcast platforms please to seek out if you are just randomly come across to us when we talk about any kind of technology related topics and we'll continue to do that as long as we can, I suppose. And we welcome any guests in relevant topics that we can. Yeah, hopefully you guys had a bit of awareness bit of understanding on the technology behind you know in your day to day life today. And we hope to bring you more and more topics in the coming weeks.

Amit Sarkar:

Yes thank you so much Rinat for ending that. Ending it on. High. I think sometimes we stop appreciating the marvel that we have in our hands. And we just end up scrolling through Instagram and Facebook etc. But there is such a I mean, so much human ingenuity has gone into making that smartphone, which is which is the culmination of so many years of efforts and innovation, that it's unimaginable. But here it is. And it's just good to understand what's happening behind the scenes. So yeah, this is our way of trying to understand it and then bring it to you guys so you can appreciate it even more and maybe you can do something with it. So yeah. Thank you so much for listening and see you next time.

Rinat Malik:

Yes, thank you very much, guys.