GPS 3 & Dual GNSS
Major update to mobile devices.
Over the last few years, there has been a lot of attention given to 5G and how it will change so much in our society. (Learn more about 5G, by reading 5G – The Hype and the Reality)
But there is a major update to our mobile devices that is getting little to no attention. Without this update, 5G’s impact on our society will be greatly diminished.
That update is the roll out of the next generation of GPS.
In this article I will explain how GPS works, debunk some of the myths, then explain the GPS update and why it is needed.
How GPS Works.
Let me explain how GPS works, you maybe surprised.
A Global Positioning System (GPS) is a satellite-based navigation system made up of at least 24 satellites. Each one of these satellites travels around the earth two times a day each transmiting a unique radio signal.
This is a one-way signal; GPS satellites do not receive a signal from your mobile device.
This signal is saying, “At this time, the satellite is at this location”. Your mobile device then uses this information to figure out the distance between itself and the GPS satellite.
How is distance is calculated?
Remember the last time you watched a firework display. You saw the firework explode then a few seconds later you heard the explosion. That’s because the sound had to travel over a distance to reach your ears.
Now imagine your friend is standing the same distance away with a loud speaker shouting out the current time.
They yell into the loud speaker, “its 10:01 am”. By the time you hear, “its 10:01“, its now 10:02 am. That means it took 1 second for their voice to reach your ears. Knowing that sounds travels at a speed of 343 meters per second (1125 feet per second), we can quickly calculate your friend is 343 meters (1125 feet) away from you.
That’s exactly how the GPS Satellite signal works. When a signal from a GPS Satellite is received by our mobile device, our device can calculate the distance between itself and the GPS Satellite. Except the signal is traveling at the speed of light which is 299,979 km per second (186,282 miles per second)
Now that we know the distance from a single GPS satellite then how do we know our location.
We use a process called trilateration.
Using a simple two-dimensional example, let’s imagine we have three GPS satellites each with a known position in space.
The first satellite broadcasts a signal and our mobile device calculates the distance between itself and satellite 1.
We then can draw a circle, equal to the calculated distance, around satellite 1.
Now we receive a signal from a second satellite, we calculate the distance and draw another circle.
With two satellite’s, we can see that our mobile device could be at either of the two places where the circles intersect (red dots).
If we add our third satellite, we can pinpoint our location (red dot).
Myths.
If we are to believe Hollywood, we would believe that GPS can consistently locate our precise location within centimeters (half an inch). All we have to do to confirm our belief is turn on Google Maps and ask for directions.
But….
Google Maps and other GPS mapping apps are using a bit of smoke and mirrors. The true reality is, that at best, these apps can locate our phones within a 5 meters (16 feet) radius. And that’s under an open sky away from buildings, bridges and trees. Most of the time its around 12 to 15 meters (40 to 50 feet)
If you have ever used a “find my phone” app to locate your phone somewhere in your house, you will know, that the app cant pinpoint your phone under your chair’s cushion.
The app might even incorrectly show the phone is in your neighbour’s house.
The trick that most GPS navigation systems use is to look at your calculated GPS location and direction and then guess which road or path you maybe on.
Then the question arises, “who cares, if the smoke and mirrors are working, why change it.”
Imagine two self driving vehicles are approaching an intersection using our current GPS technology. They both “think” they know where they are, but they could both be off by 5 meters (16 feet) or more.
Or imagine that Boston Dynamics has finally produced a commercially viable automatous robot and it is trying to navigate along a very fine pathway.
I think we can see what could happen.
5G’s promises autonomous vehicles. But what’s truly the point, if all of these devices only know where they are within a 5 meters (16 feet) radius.
For us in the delivery industry, this margin of error is why we are still use location barcodes. Proving a shipment was delivered to a certain location simply cant work in an urban setting when the location is off by 5 meters (16 feet) or worse.
The Big GPS Update
In our explanation above, our mobile device is only receiving a single signal from our GPS satellites using one bandwidth. But, here is the thing, those satellites are transmitting multiple signals on different frequencies.
Multiple signal GPS devices are called Dual-Band GNSS (aka Multi-Band)
Up until recently, dual-band receivers would cost $5000 or more. But now low-cost Dual-GNSS chips are making their way into our consumer grade mobile devices.
By receiving two signals with varying bandwidths from our satellites, we can over come signal loss from weather, buildings and bridges. Which also means, we have a greater chance locking into more GPS satellites at one time, which means better accuracy.
On top of the cost reduction of Dual-Band GNSS chips, a set of new more robust satellite have also come on-line.
All of this simple means, if your mobile device has a new Dual-Band GNSS receiver, then two things will happen:
- Two times reduction in positioning error.
- Can provide accuracy within 30 cm (1 foot)
If you want to read more, please check out this article: https://insidegnss.com/galileo-hits-the-spot-testing-gnss-dual-frequency-with-smartphones/
If you combine this new GPS update with the faster data speeds promised by 5G and include Starlinks roll out, providing faster data speeds to rural location, within a few short years, we will really start to see and experience another large leap forward in technology.