Tag: trilateration

Understanding Real Time GPS Vehicle Tracking

We are living in an increasingly complex world where we are constantly bombarded with massive amounts of information every day.  Our world is not so simple as it once was, and while technology can be a great assistance to us in our endeavors to understand the world around us it can also be a hindrance.  Some technology is better left undiscovered by those that would seek to use it, the complexity that it takes to understand its function being too much for some people.  Luckily, real time GPS vehicle tracking is not this type of technology.

It is relatively easy to understand, and can be reduced to overly simplistic terms extremely well.  Even thought it makes use of some the most complex and powerful technology that the 21st century has to offer, the actual function of the technology itself is easily intelligible and intuitive. You can understand real time tracking without having to have the smallest bit of technical understanding. It may appear to work “magically” to some people, but it can be relied upon in its “magic.” The information it provides is easily translatable, meaning that people of all positions and stations can understand what the GPS tracking system is communicating.

Real Time Vehicle Tracking Basics

Even though you don’t need to understand much about how a real time GPS vehicle tracking system works in order to get some benefit from it, it is still a good idea to try and understand the way this technology works so that we can better ascertain its limitations and costs. We need to be thoughtful consumers if the things we buy are to have the maximum amount of positive impact on our lives or our business.

With all things GPS, we should start with the Global Positioning Satellites that orbit the earth. There are over 20 of these satellites continuously transmitting data on a specific radiowave frequency that can be read by specialized receivers. The information contained in these transmissions is critical for how portable GPS devices are able to calculate their position. The data contained is the position of the satellite and the time that the transmission was sent.

Once a GPS device has received enough of these signals (3 signals from 3 different satellites) it is then able to calculate its position using a process called trilateration. What it does is it takes the know location of three or more objects, in this case the GPS satellites, and uses the known distance from these locations, which is calculated by taking the amount of time between when the GPS signal was transmitted and when it was “heard” by the GPS tracking device and then multiplying that time by the speed of the radiowave, to find out exactly where the GPS device you are holding is.  It is a little complicated when talked about this way, but it is actually quiet easy to understand when properly explained.

This video does a great job of communicating the basic principles of how a GPS device figures out its position (it is made for kids, but the information is great):

The acting in this film is, in a word, terrible, but the information contained within it is pretty informative if you ask me.

Now that we understand how a GPS device calculates its position we now need to understand what give real time GPS vehicle tracking its real time component. After all, such things as GPS navigation, golf GPS, and data logging GPS do not have a real time component to their GPS capabilities. So what makes real time GPS tracking real time?

The answer to this question is found in cell phone technology.  Once a GPS tracking device has figured out its location it needs to be able to communicate that data to a third party so that tracking can occur in real time.  Otherwise the device is just a simple GPS data logger.  While some GPS tracking systems also employ radio signals to transmit the data to a tracking unit (such as the Garmin Astro GPS pet tracking system), this is not the norm and is not really feasible for vehicle tracking applications.  GPS vehicle tracking depends on cell phone technology to transmit the data from unit to server where it can then be processed by GPS tracking software.

Because real time vehicle tracking depends on both GPS signals from above and on cell phone signals from below there are some limitations to its ability to track a vehicle.  One of them is that if they are obstructed from receiving a signal from the GPS satellite then they cannot be tracked.  While GPS receivers have grown considerably in strength over the last several decades, there are still some issues with being able to receive a signal in some conditions.  Extremely inclement weather, traveling under ground in a tunnel, or even navigating amidst tower sky scrapers can affect your GPS’s ability to get a lock on your location. A-GPS (Assisted GPS) tries to mitigate these problems by getting help from cell phone signals and has proven to be more accurate than simple GPS, but even that is not fool proof.

The second limitation for a real time GPS tracker is the need for a constant connection to the cell phone grid. If a device looses cell phone reception is no longer is effective at being a real time tracker. There are several things that could result in a signal being lost, but the most common are that the area is remote and has not access to cell phone towers or that the terrain interferes with the signal, like in a gully or ravine.

Another thing about relying on a cell phone grid is that you generally have to pay extra fees for using it. Most real time tracking systems are going to come with a monthly subscription fee that can run you anywhere from $9.99 to $50 depending on how many location requests you make or the capabilities of your providers GPS tracking software. This can be a real back breaker for those that have barely enough to fork out the considerable up front device purchase price.

But if you can stomach the expense and have a need for GPS vehicle tracking then adding a real time tracker to your repertoire is going to be very nice. They are very powerful at what they do, and if you plan on tracking a vehicle that mainly uses the urban landscape for its activities you should have no problem getting a real time, 24/7 picture of the vehicles activities. If you can hardwire the real time GPS vehicle tracking device to the car or truck then you should continuous tracking capabilities. This set up is particularly useful for fleet tracking, car tracking, and teen tracking.

Cell Phone GPS Tracking

Cell phone GPS tracking is a little tricky to talk about because mobile phones have GPS-like capabilities without having to be GPS devices.  So, in some cases, a cell phone is able to be tracked even when it doesn’t have a GPS receiver installed in it.  The reason behind this is rather simple and has everything to do with a principle I have already covered on this site: trilateration.

Once you understand the basics behind this principle you will see that is is obvious that a cell phone could be tracked whether or not it was GPS enable.  Simply put, trilateration takes the know distance of an entity from 3 or more objects to calculate the exact location of that entity.  I know, that sounds confusing – but it really isn’t.

Imagine that you are sitting somewhere in a room.  The room is a 10×10 square and you are somewhere in it and you want to find out exactly where you are in the room.  There is a desk in the middle of one of the walls that you are 5 feet from.  On the exact opposite wall there is another table in the middle of the wall that you are exactly 5 feet from as well.  Then there is a mirror on the third wall that you are looking at yourself from 5 feet away.  Where are you in the room?

If you answered, “In the center.”  Then you already know everything you need about trilateration to completely understand how a cell phone can work without actually having a GPS tracking device installed in it.

Let’s use the example of the two table and the mirrors from above to help us understand this.  The tables and the mirrors here represent cell phone towers that are dotted across urban landscapes all over the country.  In my city, they are dressed up to look like palm trees or other pleasant things but you still know what it is, a cell tower.

These cell towers transmit cellular signals out to mobile phones.  The signals travel at a constant speed which makes finding out the distance between cell phones and cell towers very easy.  All one must do is record the amount of time it takes between the time that the signal was transmitted by the tower and when it arrived at the cell phone.  You then take the time that it took and multiply it by the speed at which the signal traveled.  This looks something like this:

Distance Traveled = Speed x Time

This will give you the cell phone’s distance from the cell tower.  Since the cell phone provider (a cell phone provider is a company like Nextel, AT&T, Verizon, TMobile, etc.) knows exactly where they cell tower is, they know that the cell phone is within x number of feet from that tower.  Imagine a big circle surrounding the cell tower in the map in your mind.

Now imagine a second cell tower that also transmits a signal that is picked up by the cell phone.  This is a certain distance from this second cell tower so imagine another circle around this second tower.  Where the two circles intersect are the potential locations of the cell phone as far as the cell phone provider is concerned.

Once you add a third tower in the mix you should have a pretty darn good fix on the location of the cell phone – all without the use of GPS tracking devices.

It is important to understand that this is also exactly how GPS works, but instead of cellular towers on the urban landscape you have satellites in the heavenly firmament  and instead of circles you have spheres around each satellite.  This is pretty amazing stuff if you ask me.

Now that we have learned that cell phones can have GPS tracking without actually having a GPS device installed in it, let’s take a look at what can be done with GPS cell phone tracking.

There are several different applications that should be considered, but we will only take a look at three to give us a flavor of just how awesome this type of technology can be.  Cellphone GPS tracking can be used for navigation purposes, to monitor a loved ones activity, and to learn useful things about your current location.

Cell Phone Tracking and Navigation

There is little doubt that the use of GPS for navigation purposes is a huge industry.  That was, after all, one of the initial impetus behind the Department of Defense creating the satellite system.  They wanted a way to know where they assets were but they also wanted to us it to tell where there assets were going.

GPS navigation has become the norm in many families across America with Garmins or TomToms or Magellans replacing the friendly AAA triptiks of two decades ago.  I still remember as a child going into the AAA office with my mother to get a triptik ready for a family vacation.  Now, you just enter your trip into the GPS and it does all the routing for you.

Cell phone companies realized that this was a huge market and that their technology could easily break into it.  They could either us GPS technology to do the mapping just like a Garmin can, or they could leverage the cellular signals they were already broadcasting to create new navigation systems.  Some companies decided to go with GPS and other stuck with the cell signal.

Either way you look at, cell phones now use GPS or a GPS-like technology to give turn-by-turn directions to drivers all over the country.  While this isn’t GPS tracking as most would think of it, it still is using a cellular phone to track and record position information.  It can tell people how to fast you are traveling, an ETA (estimated time of arrival), and it can actively tell you your current location.  This is GPS tracking if you ask me.

As we will see this information can be used for other purposes other than navigation.

Cell Phone GPS Tracking And Location Monitoring

Location monitoring is another useful application of GPS in cell phones.  Unlike the type of tracking that goes on for navigation purposes, the information used to track the location of a cell phone is actually transmitted from the cell phone back to the cell company.  This process is often referred to as “tracing a cell phone.”

We hear about it all the time if we watch any crime show drama.  They are always putting “a trace on the cell phone” or “triangulating the cell’s position” – especially when a kidnapper or other bad person decides to call up our favorite detectives for a to have a chat.  Essentially what is happening in these instances is that a third party, in the case the police, are using information gathered by a cell phone provider to find the location of a caller.

The police obviously find this information particularly useful, especially when responding to a 911 call made from a cell phone.  But there are other interesting applications for this as well.  One of them is to GPS track a teen in order to monitor their driving habits or to make sure that they are not lying to you about where they are. All teens use cell phones these days so this service is relatively painless for you and for them.  It is also relatively cheap and can be as little as $6 a month for 4 phones.

Another application of cell phone tracking is for getting fitness performance metrics.  Just take your phone with you on a run or bike ride when you have a certain application installed and you will automatically get information like the average speed of your run and the distance traveled.  You will even be able to see your entire course on a mapping application like Google Maps.

Another bit of information that cell phones have been regularly used to monitor is the activity of a spouse or lover suspected of cheating.  In situations where this could be going on it is imperative that the suspecting spouse snoops around the other’s activities.  This can involved GPS tracking or it can be through other methods, it just has to get done.  Cell phone GPS tracking can be a good solution for individuals that find themselves in this situation so you might want to consider using it.  It might be difficult if you have separate cell phone plans or they regularly pay the cell phone bill since any tracking charges will undoubtedly show up on your bill.  But if you are in charge of this you might be able to set up GPS tracking without them even knowing it.

Finally, cell phones can be a great way to introduce GPS into a kids life.  You could use the phone for GPS tracking for kids or you could just use it to help your child learn about the world around them.  Kids do great with mapping applications and it can really help them get a better understanding of the world around them.  They can also be used to keep kids safe in case of an emergency or other terrible occurance.

These types of location monitoring and tracking applications are going to become more prevalent over the next decade as we experiment with this relatively new technology.  It will be interesting to see how it all pans out.

GPS Tracking Cell Phones and Random Data

The last way that I wanted to talk about was the use of cell phones to communicate random data based upon the location of the user.  What I have in mind for this are apps (like those found on the iPhone) that tell you something specific that you can take action on or find interesting about your location.

If you are on a street and are feeling like Chinese food but don’t know the area you can type “Chinese” into this cell phone tracking app and it will give the location of the 5 closest Chinese restaurants along with some customer reviews and relative price points for the meals.

This idea can have many different applications in areas as diverse as real estate and movie theaters; fishing and ball room dance classes; or finding a replacement part on a car and finding a nanny.  Whatever someone is willing to write an app for the GPS tracking cell phone is going to be able to provide laser-like access to position information that can be used to make life simpler and finding the closest solution to a problem easier.

All of these applications of cell phone GPS tracking have current uses today, but can only be expected to be improved upon with time and advances in personal tracking technology.  You simply cannot underestimate the power of GPS tracking in a cell phone package – it is, in my opinion the future of all things GPS.

Free GPS Cell Phone Tracking

I have compiled a short list of free GPS tracking software and applications, with the majority of the applications working on mobile phones.  Feel free to check out this list and see if your cell phone is already compatible with one of the systems.  If it isn’t, you could always buy a new phone, right?

I also have made some comments on how free free GPS tracking really is – if you are interested in reading those as well.  To sum up I said that if you already have everything that you need (i.e. GPS smartphone and a robust data plan) then it will truly be free.  If you don’t have either of these things then getting free GPS cell phone tracking is going to be anything but free.  You will have to pay the costs associated with getting the new phone and subscribing to the data plan.

How Do GPS Tracking Watches Work?

All GPS tracking devices, including GPS tracking watches, work around a few basic geometric principles. These principles are described by the trilateration equation. Trilateration uses the know location of two or more points of reference (the more the better) and the measured distance between the subject and the reference points to give an exact location for the subject. To aid our understanding of this geo-speak, take a look at the two dimensional example below:

GPS Tracking Example

You are standing at point B in this picture (found where all three circles intersect). Let us imagine that you are standing out in the middle of nowhere and you want to find out where ‘here’ is. On your wrist is your GPS tracking watch, ready for instances just like this one. P1, P2, and P3 represent satellites in the NAVSTAR GPS constellation run by the US Government. There are twenty-four of these satellites orbiting approximately 12,600 miles (20,200 km) above the earth surface that are constantly transmitting microwave signals. At the same exact time, these satellites transmit a signal with information concerning their current location and the time that they were transmitted. The colored circles represent the path of the signal from the satellite at a specific time, let us say 8:45:03 AM, August 5, 1991.

Your GPS tracking device is designed to pick up these signals and record the time at which they arrive. Because the signals from the satellites travel at approximately the speed of light, knowing the difference between when the signal was generated and when your watch picks it up will let you know the distance between you and the broadcasting satellite. This is a very simple physics equation (speed x time = distance). When you combine this with the known location of each of the satellites (this information is contained in the signal that your watch picks up) your GPS tracking device has all the information it needs to give you an exact location for where you are.

GPS Tracking Is More Than Trilateration

Your GPS tracking watch will then do something with this new found information. If your watch is a data logger it will simply log your location in its memory and possibly give you a display of your longitude, latitude, and altitude. Data loggers are often simple devices that are used by bikers, hikers, and joggers to record their journeys, track the distances traveled for training purposes, or to build maps or guides if they are exploring new territory. This type of device has many useful applications, but unless you have a map with you in the middle of nowhere (Point B) this type of information will do you no good. If you are every stranded in some nondescript Point B I hope that you don’t have a data logger.

Instead, you want a tracking device that is going to be a data pusher. What these GPS devices do is they transmit their position information at specified intervals to a central database. This database can often be accessed through the internet, providing valuable information to the search party looking for you. Common applications of data pushers include tracking delivery vehicles, locating stolen property (LoJack), or keeping tabs on an object’s or individual’s location. Data pushers are extremely powerful because of the information they provide – but with this power also comes significant risk of abuse. The most common form of data pushing devices are used for GPS tracking are cell phones.

I hope that was a fairly straight forward explanation of how GPS tracking watches work. It was fairly simplified, so if you are interested in finding out more about the complex mechanics I would recommend checking out the following articles:

How To Teach Your Kids About How GPS Works

When teaching your child about their kids GPS, you are going to want to find a way to relate the information in a way that they can understand.  It doesn’t matter what type of GPS you are using with your child – it could be a short range child locator, a GPS tracking watch, or even a covert GPS tracking device – you just need to find a way to give your child a way to wrap their mind around the idea.

A basic understanding of math is always a good thing to have, but if your child is too young to fully grasp things like geometry they might be old enough to measure things.  If you are in this situation, this quick activity may help you out:

  1. Grab a couple of paper plates out of your pantry.
  2. Draw a few satellites in the center of each paper plate.  This will be a great time to explain what a satellite is and how they fly in the sky around the earth.  You can make sure that they know that satellites make up the Global Positioning System (GPS).
  3. Arrange the paper plates so that they resemble the picture found above.
  4. Take out a ruler and measure the distance between each ‘satellite.’ Take the time to explain how this is important for the child locator that they get to use every day.
  5. Now explain that the child locator knows exactly where the satellites are in the sky around the earth.  It can measure where the child is just like you did together with the ruler.
  6. Now take out your cell phone or your child’s GPS kids phone.  Explain that their GPS device for kids works in the same way the phone does – it talks through the air to another phone.  That is exactly what the kids GPS does – it talks through the air to someone else.
  7. And finally, tell them that the person that the GPS tracking watch talks to also talks to Mom and Dad.  That is how you know that the child locator works and why you got it for them.

Most importantly of all, you want your child to fell like they are safe with their GPS tracking watch and that it makes them valuable/special.  This will give them a better understanding of the world that they live in and will enable them to be productive little guys.