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Saturday, December 19, 2009

PS tracking devices: Powerful tools for vehicle tracking or as a people locator

Any business that has a fleet of vehicles, boats, farm or construction equipment would benefit from the installation of GPS tracking devices. Not only are they extremely useful for vehicle tracking they are can be used as a people locator. GPS uses a network of 24 satellites in staggered orbits around the Earth. At any time, from any location on the planet, four of these satellites are "visible" -- capable of receiving and sending signals. This means tracking devices can by used at any moment in time for vehicle tracking or as a people locator to track staff.

When the receivers of the tracking devices are activated, they obtain the following information from the 4 satellites they can communicate with: latitude, longitude, altitude and time. The location data is translated and displayed on a digital street map viewed on a screen built into the unit. The process repeats as the receiver moves and the unit constantly updates the screen. If there is vehicle tracking or people locator unit in a fleet of taxicabs, for example, the central dispatcher can monitor each vehicle's location, stop time, route taken and speed. An even more critical application would to have these GPS units installed in a fleet of ambulances or police patrol cars.

Another extremely important application for GPS involves tracking stolen vehicles. With tracking devices installed vehicles can be rapidly located and recovered, often within minutes of the theft. In addition, the starter can be enabled or disabled depending on the situation. Remote door unlock is also available. GPS vehicle tracking devices can also be found on boats, planes, movie making gear and laptop computers. This amazing vehicle or people locator space technology has unlimited earthbound uses.

Not only can tracking devices be used for vehicle tracking they are also proving very useful as a people locator. They can bring peace of mind to parents as they can know where their child is, at any given moment. All it takes to know is a phone call to the company which monitors the position of the tracking device and you will be able to find out where the unit is – which can be great for worried parents. Of course, this is not the only use for these neat little devices, they can also be used to keep track of people who have gone out into the great outdoors, such as climbers, trekkers, and walkers.

GPS Tracking Devices navigation & tracking solutions

Aviation, Boating, Car Navigation, Fishing, Golf, GIS, Hunting/Outdoors, Laptop GPS, Mac GPS, Military GPS, OEM GPS, Vehicle Tracking

GPS Tracking and its Applications

Being able to pinpoint the location of a device on planet Earth raises some interesting ideas and applications. Primarily, GPS (Global Positioning System) was intended to be released to the consumer market as a way to aid navigation.

However, since the price of the technology surrounding GPS has fallen, many companies have found new ways to apply it. Indeed, the price of associated technologies has also fallen dramatically since the inception of GPS, which has lead to many innovations, amongst them GPS Tracking.

GPS and how it works

Before we look at GPS Tracking in detail, we first need to establish what it is about GPS that makes this such a unique and useful application of this technology.

The principle behind GPS systems is that they are able to use triangulation to calculate their coordinates on Earth by measuring the time taken for signals from various satellites to reach them.

The GPS software is also intelligent enough to compensate for any irregularities in the signal strength and clock differences between itself and the GPS satellite network by using signals from four separate satellites to improve accuracy.

Usually the coordinates are then used to locate the GPS system on a map, which is either displayed to the user or used as a basis for calculating routes, navigation, or as input into mapping programs. For example, specific coordinates can be stored as waypoints allowing the user to retrace their steps by calculating the direction and distance to each waypoint that they have stored.

GPS Tracking

In fact, it is this use which represents the simplest form of GPS tracking. The user is able, using a portable GPS system, to keep a track of where they have been, in order to be able to either retrace their steps, or follow the same path again in the future.

When combined with other technologies such as GPS phones, this also gives the possibility for other users of GPS to follow in the footsteps of the initial user; which can be a useful application of GPS tracking for field activities.

Where GPS tracking comes into its own, however, is when it is combined with other broadcast technologies such as radio. GPS watches, for example, can be fitted with a GPS receiver which is capable of calculating its position, whilst also broadcasting that using a miniature radio transmitter.

The signal is relayed to a central command center equipped with GPS software systems which can track the position of the wearer, and either store it as a path or relay that information to a third party.

That third party could be an anxious parent, or the police. In fact there are a variety of GPS phones and wristbands which are sold in conjunction with a service which enables third parties to find out where their charges are at any time of the day or night.

GPS Vehicle Tracking

This is particularly useful when using GPS units attached to vehicles which have distinctive identification such as chassis numbers. The same principle applies as to a GPS tracking device designed to be worn by a human, except that the GPS is integrated with the vehicular entertainment system.

This serves two purposes. On the one hand, it provides the driver with an integrated GPS system, without the necessity to purchase a car navigation system, or a PDA GPS system, whilst also offering the possibility to relay that information via a radio or cell phone transmitter.

In fact, these systems have already been tried in the field, primarily as a vehicle locator in the event that the vehicle to which the GPS vehicle tracking system is attached is stolen. The police, once informed, can find out from the control center when the vehicle is, and proceed to track it physically.

A useful consequence of being able to use GPS vehicle tracking to locate a vehicle is that the manufacturer can also use the information to alert the driver as to when they near a service center.

If, along with the GPS coordinates, the system relays telemetry information such as the status of the engine, time since the last service, or even information not relating to defects, the receiver of this information can make a decision as to what kind of alert to pass on to the driver.

Coordinated Tracking

This also opens up the possibility to allow for coordinated vehicle tracking, in which GPS tracking is used to share location information between several vehicles, all pursuing the same end goal.

It is an approach that has been used successfully in conjunction with GPS fishfinder units which help fisherman to locate, track and catch fish. These units are more sophisticated than the average GPS unit, comprising other features such as depth gauges, tide time information and so forth.
The basic GPS functionality is the same however, and units can either share that information with each other, or a central point. The central point can also be one of the fishing vessels, and it has on-board computer systems capable of reconciling all the locator information along with a map, thus allowing the different vessels to coordinate their actions.

This also has military applications, of course, where units can share, in real time, information about their location, even when line of sight is no longer possible. In the past, this was done by relaying often inaccurate map co-ordinate estimations; now the locations can be called in with almost absolute accuracy.

Consumer GPS Tracking

Despite its’ hitech military and commercial fishing applications, as well as use in aviation GPS, the principle application of GPS tracking will be in providing an enabling technology to augment existing systems.

These systems will include cell phones and vehicles, usually in conjunction with a central point of service designed to keep track of the location. The reason for this is to keep the cost of the actual GPS unit down as much as possible in order to provide useful technology to consumers at the right price.

he Many Benefits and Applications of GPS systems

In order to fully appreciate the various possibilities that the GPS technology offers consumers, one first needs to be aware of exactly what the applications and benefits are of this important technology.

This article discusses what GPS systems are, how they work, and what current uses have been found for it that can be acquired on the general market. Of course, there are new applications being developed all the time, as the surrounding technological environment becomes more advanced.

What is GPS

Originally conceived as a navigation aid, Global Positioning System, or GPS systems , has since grown from relatively humble beginnings as different supporting technologies have been developed which fall into consumer budgets.

All that GPS does is provide a set of coordinates which represent the location of the GPS unit with respect to it’s latitude, longitude and elevation on planet Earth. It also provides an accurate co-ordinate time, which is usually as accurate as an atomic clock.

The actual application of GPS is what leads to navigation systems, GPS tracking devices and navigation using GPS mapping. GPS in itself does not provide any functionality beyond being able to receive satellite signals and calculate position information.

How GPS systems work

The actual theory behind GPS systems is very easy to appreciate, since it is exactly the same as traditional triangulation. If one imagines an orienteer needing to locate themselves on a map, they first need to be able to find at least three points that they recognize in the real world, and pinpoint their locations on the map.

They can then measure, using a compass, the heading that would be needed to take them from the point on the map to their current position. A line is then drawn from each of the three points, and where the three lines meet is where they are on the map.

Translating this into the GPS world, we can replace the known points with satellites, and the direction with time taken for a signal to travel from each of the known points to the GPS receiver. This enables the system to work out roughly where it is located – it is where the circles representing the distance from the satellite, calculated on the basis of the travel time of the signal, intersect.

Of course, this requires that the GPS locator has the same coordinated time as the satellites, which have atomic clocks on board. To do this, it cross checks the intersection of the three circles with a fourth which it acquires from another satellite.

If the four circles no longer intersect at the same point, then the GPS systems know that there is an error in it’s clock, and can adjust it by finding one common value (one second, half a second and so on) that can be applied to the three initial signals which would bring the circles to intersect in the same place.

Behind the scenes, there are also many complex calculations taking place which enable the system to compensate for atmospheric distortion of the signals, and so forth, but the principle remains the same.

Tracking Devices

One of the easiest applications to consider is the simple GPS tracking device; which combines the possibility to locate itself with associated technologies such as radio transmission and telephony.

Tracking is useful because it enables a central point to monitor the position of several vehicles or people, in real time, without them needing to relay that information explicitly. This can include children, criminals, police and emergency vehicles or military applications.

The tracing devices themselves come in various different flavors. They will always contain a GPS receiver, and some GPS software, along with some way of transmitting the resulting coordinates. GPS watches, for example, tend to use radio waves to transmit their location to a tracking center, while GPS phones use existing cell phone technology.

The tracking center can then use that information for co-ordination or alert services. One application in the field is to allow anxious parents to locate their children by calling the tracking station – mainly for their peace of mind.

GPS vehicle tracking is also used to locate stolen cars, or provide services to the driver such as locating the nearest gas station. Police can also benefit from using GPS tracing devices to ensure that parolees do not violate curfew, and to locate them if they do.

Navigation Systems

Once we know our location, we can, of course, find out where we are on a map, and GPS mapping and navigation is perhaps the most well-known of all the applications of GPS. Using the GPS coordinates, appropriate software can perform all manner of tasks, from locating the unit, to finding a route from A to B, or dynamically selecting the best route in real time.

These systems need to work with map data, which does not form part of the GPS system, but is one of the associated technologies that we spoke of in the introduction to this article. The availability of high powered computers in small, portable packages has lead to a variety of solutions which combines maps with location information to enable the user to navigate.

The first such application was the car navigation system, which allows drivers to receive navigation instructions without taking their eyes off the road, via voice commands. Usually, these systems take their map data from a CD which can be replaced when the driver moves from one geographical location to another.

Then there are handheld GPS units, such as those from Garmin, which are commonly used by those involved in outdoor pursuits, and only relay very limited information such as the location, and possibly store GPS waypoints. A waypoint being a location that is kept in memory so that the unit can retrace the path at a later time.

More advanced versions include aviation GPS systems, which offer specific features for those flying aircraft, and marine GPS systems which offer information pertaining to marine channels, and tide times.

These last two require maps and mapping software which differ vastly from traditional GPS solutions, and as such can often be augmented with other packages designed to allow the user to import paper maps or charts. The mapsource software is one such industry standard package.

There are even GPS solutions for use on the golf course. Golf GPS systems help the player to calculate the distance from the tee to the pin, or to know exactly where they are with relation to features such as hidden bunkers, water hazards or greens. Again, specific maps are needed for such applications.

Choosing the Right Type of GPS

In order to be in a position to choose from the various GPS solutions that are present in the consumer marketplace, it is necessary to have a reasonable understanding of what they can offer, as well as what the user is expecting from the solution.

There are several components that need to be looked at. There is the GPS receiver (or antenna) itself, which plays an important part. Then there is the portion of the system which uses the received information to estimate where the device is located on an internal map.

Then there are the various capabilities for route planning and recording, which vary from unit to unit. Finally, the display portion of each solution type can vary considerably, from limited location information to full color three dimensional maps of the immediate surroundings and advised route.

How it Works

All GPS solutions are based on the same premise, and it is a good idea to at least be aware of the underlying technology so that a reasonably informed decision can be made as to which application of the GPS technology is appropriate for the user in question.

GPS revolves around the possibility to capture signals from satellites which orbit the Earth at known positions. Each satellite has a separate identification and sends a signal which the GPS software can use to calculate the distance from the device to the satellite.

Much like regular orienteering triangulation, this allows the software to estimate its own position from several (at least 3, preferably 4 or more) signals, by finding the point in space at which the circles representing the distance from each satellite intersect.

From this location information, the software can then pinpoint the devices location on a map and use the information for a variety of different operations, from simply displaying the location, to adjusting a proposed route based on the actual position of the device compared to the desired position.


There are three broad classes of application – road, hiking and maritime – and each is further subdivided into other types which offer different features depending on the exact use to which they will be put and the environment that they will be operating in.

One important thing to remember is that this technology does not allow the transmission of actual mapping data via the satellites. It is purely concerned with the location of the device in space.

The first application we shall look at is the in-car (or in-vehicle) GPS. These units need to be accurate, safe, and contain details of all the roads, and important addresses (gas stations, railroads etc.) and points of interest for the geographical area in which the device will be operating.

These devices start with those which are part of the in-vehicle entertainment system, which ties them to a single vehicle. Obviously this will usually make them much more integrated with the vehicle itself, but also suffers drawbacks such as not being able to remove the unit from the vehicle.

Portable devices suitable for in-vehicle use exist, and offer a great alternative to those which are integrated with a particular vehicle. However, they will not be able to override the in-vehicle entertainment device (CD player, etc.) and so the voice commands might be drowned out by the music.

Then there are portable devices which are designed for general use, which have a limited road database, and reasonable terrain information. They are small enough to be carried in the palm of your hand, but can suffer from inaccuracies stemming from the built-in antenna and relatively low power software.

However, a recent trend has seen PDA manufacturers attaching a GPS antenna, and providing sophisticated software and maps which use the power of the PDA to give an excellent solution. They might not be rugged, but they do provide a very good base for both in-vehicle and general navigation.

Rather than having a direct connection, many PDA GPS solutions use Bluetooth as a means to communicate with the GPS receiver. This makes them more easily installed in, and transported from, vehicles.

Finally, maritime units need very specific features, not least being waterproof, and containing additional information relating to tides and information that can be plotted on nautical charts. Their maps are also very specific, giving undersea elevations as well as navigable channel information.

This includes devices such as fishfinders, which build other fishing related features into the basic GPS unit. A fishfinder is very useful for positioning, tracking and helping the fishing enthusiast to locate fish at sea.

Associated technologies such as GPS tracking have also evolved, where the user wears a watch which relays their position via radio to a central control center. This tracking information is then used in conjunction with an alert system to track anything from vehicles to people.

Updates & Mapping

When choosing a GPS, it is important to bear in mind that each type will be updated in a different way. For example, dedicated in-vehicle units tend to be updated via CD, which has to be purchased, usually at a high price, from the manufacturer.

Those which are attached to a PDA, as well as most handheld dedicated GPS devices are usually updated via a PC. They also need maps, but said maps can usually be acquired at a much lower price than the dedicated branded ones needed for other systems.

Being able to update the device easily and at a reasonable cost is a very important part of the decision process; unlike other consumer devices that you purchase, the cost of ownership of a GPS unit is proportional to its usefulness.

The less you spend on maintaining it, the less useful it becomes since the road networks are always changing. This is perhaps less important for devices aimed at hiking and orienteering, but could be a factor in deciding whether a multi-function device is better than one dedicated to a specific use.

Specific software vendors have solutions for preparing maps which can be uploaded into the GPS unit. For example, many are based around the mapsource system which permits users to define their own maps, perhaps scanned from a real one, in order to get the most out of their GPS.

Accuracy & Portability

If accuracy is paramount, then it is also important to choose a unit that is equipped with WAAS (Wide Area Augmentation System). This is a terrestrial service which provides additional information to the GPS which enables it to increase its accuracy.

WAAS equipped devices might be especially useful for road users and those involved in either door to door selling, or providing a service which requires them to be able to pinpoint their position right down to a few feet.

On the other hand, it is useless to purchase a WAAS capable system if the service is not available in the area in which the device is to be used. Most big cities should provide WAAS coverage, and it can also help to compensate for lack of GPS signals due to blocking by tall buildings.

The other way to avoid this is to use a better antenna, but this will hurt the portability of the device. If portability is a key part of the decision process, then it will usually be a trade-off against accuracy, whether that accuracy stems from poor GPS signal acquisition, or less powerful triangulation software coupled with a less detailed map.

The Choice

In the end, the choice is reasonably straightforward – buy the most expensive GSP that fits your needs; if price is a deciding factor, then buy the most expensive one you can afford which fits your needs.

Try to think about the following:

▪ Portability
▪ Features
▪ Mapping and Updating
▪ Environmental Features

Portability is affected by weight and size, as well as the antenna. This could have an effect on the features that the device offers – clearly if the screen is tiny, and the whole unit is about the size of a cell phone, then some advanced features will not be fitted.

The mapping and updating capabilities are also important. Should it be able to accept any old map from a PC, or is it enough that the unit is replaced after 5 years? Technology moves almost as fast as the roads are updated, so this could be an option.

Finally, are there any specific environmental options that are needed, such as waterproofing, rugged shock-proof design, or other features that make one device more attractive than another?

Answering these questions will help determine what type of GPS is right for you, and at the right price.

How GPS Works

For those who are unfamiliar with the term, GPS stands for Global Positioning System, and is a way of locating a receiver in three dimensional space anywhere on the planet.

GPS remains one of the most important inventions of our time, and has so many different applications that the technology is continually being improved in order to make the most of it.

To understand exactly why it is so useful and important, we should first look at how GPS works. More importantly, looking at what technological achievements have driven the development of this fascinating positioning system.


In order for GPS to work, a network of satellites was placed into orbit around planet Earth, each broadcasting a specific signal, much like a normal radio signal. This signal is powerful enough that it can be received by a reasonably low cost, low technology aerial.

Rather than carrying an actual radio or television program, the signals that are broadcast by the satellites carry data that is passed from the aerial to the GPS software.

The information is specific enough that the GPS software can identify the satellite, it’s location in space, and the time that the signal took to travel from the satellite to the GPS receiver.

Using many different signals, the GPS software is able to triangulate the position of the receiver. The principle is very similar to that which is used in orienteering – if you can identify three places on your map, take a bearing to where they are, and draw three lines on the map, then you will find out where you are on the map.

The lines will intersect, and, depending on the accuracy of the bearings, the triangle that they form where they intersect will approximate to your position, within a margin of error.

GPS software performs a similar kind of exercise, using the known positions of the satellites in space, and measuring the time that the signal has taken to travel from the satellite to Earth.

The result of the triangulation of at least three satellites, assuming that the clocks are all synchronized enables the software to calculate, within a margin of error, where the device is located in terms of its latitude (East-West) and longitude (North-South).

Timing & Correction

In a perfect world, the accuracy should be absolute, but there are many different obstacles which prevent this. Principally, it is impossible to be sure that the clocks are all synchronized.

Since the satellites each contain atomic clocks which are extremely accurate, and certainly accurate to each other, we can assume that the problem lies with the GPS unit itself.

Keeping the cost of the technology down to a minimum is a key part of the success of any consumer device, and it is simply not possible to fit each GPS unit with an atomic clock costing tens of thousands of dollars. Luckily, in creating the system, the designers also defined how GPS works out whether it’s clock is accurate or not.

There are a few solutions. The first is to fit a separate receiver which can receive a terrestrial signal from a nearby atomic clock. This technology exists for clocks which cost a fraction of the tens of thousands that would be required for a true atomic clock, but would still add tens, if not hundreds of dollars to the price of the GPS receiver.

The solution that was chosen uses a fourth satellite to provide a cross check in the triangulation process. Since triangulation from three signals should pinpoint the location exactly, adding a fourth will move that location; that is, it will not intersect with the calculated location.

This indicates to the GPS software that there is a discrepancy, and so it performs an additional calculation to find a value that it can use to adjust all the signals so that the four lines used in the triangulation intersect.

Usually, this is as simple as subtracting a second (for example) from each of the calculated travel times of the signals. Thus, the GPS software can also update its’ own internal clock; and means that not only do we have an accurate positioning device, but also an atomic clock in the palm of our hands.


Knowing where the device is in space is one thing, but it is fairly useless information without something to compare it with. Thus, the mapping part of any GPS software is very important; it is how GPS works our possible routes, and allows the user to plan in advance.

In fact, it is often the mapping data which elevates the price of the GPS solution; it must be accurate and updated reasonably frequently. There are, however, several kinds of map, and each is aimed at different users, with different needs.

Road users, for example, require that their mapping data contains accurate information about the road network in the geographical location that they will be traveling in, but will not require detailed information about the lie of the land – they do not really worry about the height of hills and so forth.

On the other hand, hiking GPS users might wish to have a detailed map of the geographical surroundings, rivers, hills and so forth, and perhaps tracks and trails, but not roads. They might also like to adorn their map with specific icons of things that they find along the way and that they wish to keep a record of – not to mention waypoints; locations to make for on their general route.

Finally, marine users need very specific information relating to the sea bed, navigable channels, and other pieces of maritime data that enables them to navigate. Of course, the sea itself is reasonably featureless, but underneath quite some detail is needed to be sure that the boat is safe.

Fishermen also use marine GPS to locate themselves and track the movement of shoals of fish both in real time, and to predict where they will be the next day. The advent of GPS fixing has also meant that co-operative fishing has become much easier, where there are several boats all relaying their locations to each other while they locate the best fishing waters.

Special kinds of marine GPS, known as fishfinders, also combine several functions in one to help fishermen. A fishfinder comprises GPS and also sonar, along with advanced tracking functions and storage for kinds of fishing and maritime information.

Getting Started

There are a few solutions available to consumers, ranging from in-car GPS systems, which feature voice guiding, powerful dynamic route calculation, and the possibility to update the map from a CD.

Then there are handheld GPS devices, such as those from Magellan and Garmin, which store a map inside, and are usually quite rugged and designed for outdoor use. They cannot generally perform dynamic route calculation since they do not have any road information, and leave the user to find their own way from A to B.

Finally, a more recent solution has appeared on the market which uses the power of a PDA to run the actual GPS software, and uses the interface capability to attach a GPS receiver (antenna) to the unit. These tend to be the cheapest, easiest to use and most flexible solutions, but are only as rugged as the PDA to which they are attached.

More recent systems can make use of a wireless Bluetooth connection so that they can be used both as a personal navigation aid and also inside a vehicle, by having several receives with Bluetooth capabilities, and a single PDA.

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Tuesday, December 1, 2009

Satsports Rugged All-Weather GPS Helps Golfers, Cyclists, and Skiers Navigate, Re-Live Glory via Google Earth

We've already seen plenty of outdoor, rugged, handheld GPS units from the usual suspects
(Garmin, Magellan, DeLorme), but according to manufacturer, Satsports is unique in that it's the first GPS to offer "true real-time interactive navigation for skiing, snowboarding, golfing, running, cycling and automotive enthusiasts in a portable, all-weather device."

Once you finish your outdoor adventures, Satsports can connect to your computer and sync the data with Google Earth.

Priced at $490, Satsports isn't cheap, but I'll reserve judgment until I actually test it.


2.7-inch display
Li Ion rechargeable battery
90 x 55 x 16 mm
Weight: 125g
GPS receiver: SiRF Star III
Micro SD memory card slot (256MB internal RAM)
What's in the Box:

Satsports GPS unit
USB Cable
AC Power Adapter
Car mounting bracket
Car charger
Spare battery
Protective case
Bicycle mounting bracket

Tag :garmin gps gps gps tracking gps map gps maps gps earth gps unit gps receiver gps simulator
gps signals gps satellite gps-garmin-accessories-unit

What are the Best-Selling GPS Models This Year?

So far this year, these are the top 5 selling GPS models for 2009:

Garmin nuvi 255W
Garmin nuvi 205
Garmin nuvi 205W
TomTom ONE 130
TomTom ONE 125
(Source: The NPD Group/Retail Tracking Service)

Nothing too shocking here. The less expensive, basic models sell the best, with Garmin taking the top 3 places.

I'm slightly surprised that Magellan's not in the top 5, since in many ways Magellan provides more features per dollar than Garmin or TomTom. Although given Magellan's lack of consistency in its product line and persistent customer service issues, it's not terribly surprising to see them lose market share.

Monday, November 30, 2009

GPS Security Functionality

by: Jeremy Maddock
One of the most common uses of Global Positioning System (GPS) technology, by businesses and consumers alike, is to ensure security from theft, as well as human safety.
Using a GPS tracking system  is an excellent way for an individual or small business to keep track of important equipment including vehicles, machinery, and portable electronic devices, such as laptops and cell phones.
A prime example of the usefulness of GPS technology for security purposes is its abilities in the fight against vehicle theft. If you car or truck were stolen, and it had a GPS vehicle tracking  system installed, then you would be able to pinpoint the exact location of the vehicle, and see its exact coordinates on a map. You could then turn this information over to the police, allowing them to retrieve the stolen vehicle, and apprehend those responsible for the theft.
GPS technology can also be instrumental in ensuring basic human safety. This is especially true with children, as every parent’s worst fear is their child getting lost or kidnapped. Fortunately, with the help of a child GPS  tracking device, you can always know the exact location of your child. In the event of a kidnapping, you would be able to determine the exact location of the kidnapper and notify police and other emergency authorities of this information.
All in all, there is little doubt that GPS can be an excellent way to fight crime, and ensure the safety of your belongings and of your family.

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Track With Your GPS Vehicle Tracker

by: Joe Gooden
GPS is one of the newest crazes on the Market today. GPS is now available in almost everything. GPS tracks your locations from a satellite which makes it a popular feature in cars when on a trip, to help you find your way around without getting lost.
While GPS tracking can help track your location it also works the other ways. You can use GPS tracking to track someone’s location without them knowing. GPS tracking is used this way in theft deterrent system to help people recover their stolen vehicles. GPS tracking is also a new tool used to track a vehicle when someone is just driving their own car.
Why you may want to consider the use for GPS tracking is to track a non stolen vehicle but keep track of the driver. Especially if it is suspected that the driver is up to something unauthorized. GPS tracking can locate where the car is going with out tailing them or running the risk of being caught. GPS tracking devices are available in many different kinds of product at every price level to get the job done. The #1 GPS Vehicle Tracker in the market today is the Spy Matrix GPS. This GPS tracking device is small enough to be undetectable when planted on a car, person, or package. Several different kinds of GPS tracking products are available at They also offer several different products to meet all of your surveillance needs such as cameras, night vision products, listening devices and many other kinds of products to help get the job done right and prove the case.
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Practical Uses for GPS Technology

 by: Jeremy Maddock
Since the US Department of Defense established the worldwide Global Positioning System (GPS) network, it has been put to a very wide variety of uses by governments, corporations, organizations, and individuals alike.
It has been put to good use for many years in its original, and most obvious, purpose of coordinating military operations. In fact, if it weren’t for GPS, many modern military operations and practices would simply not be possible. It is also frequently used in search-and-rescue missions as well as disaster relief efforts.
In addition to this, GPS technology has proven to be instrumental in numerous scientific research expeditions, especially in very remote regions such as mountain ranges and the north and south poles.
The other side of GPS functionality, which is sometimes forgotten, is the many uses it can be put to by individual consumers. Handheld GPS units ( ) and other GPS devices ( ) are available for sale through many ordinary retail channels, and can be very useful for a variety recreational purposes. For example, having a GPS device handy when camping, hiking, hunting, fishing, or boating can be an excellent way to ensure that you don’t get lost, even if you somehow manage to wander off course.
Another common consumer use of GPS technology is for safety security purposes. Using a GPS tracking system ( ) can be an excellent way to combat crimes such as theft and kidnapping.
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Wednesday, November 25, 2009


Find All The GPS Systems Information You Need
by: J Herrera
Are you looking for some GPS systems information? Then come to see us. We have been providing technical courses and advanced GPS training on GPS systems information since a long time ago. We offer more than 20 courses on professional GPS and all you want to know about GPS systems information.
But, first than anything, what is exactly a Global Positioning System (GPS)?
It is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. At first, GPS was going to be used by military applications, but later in the 1980s, the government allowed it to be available for civilian use. It doesn’t matter the weather conditions, GPS keeps working anywhere in the world and the whole day. It is not necessary any subscription fees or setup charges to use GPS.
The second question would be: How it works?
GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers can calculate exactly where the user is by taking this information and using triangulation. In other words, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. And by repeating this procedure with a few more satellites, the receiver can determine the user's position and show it on the unit's electronic map.
A GPS receiver can calculate the latitude and longitude and track movement if it is locked on to the signal of at least three satellites. And it can determine the user’s latitude, longitude and altitude using four or more satellites. But it doesn’t end with this, because once we have the user's position, the GPS unit can calculate other information, such as speed, bearing, track, trip distance, distance to destination, and much more. So not just you can know where exactly somebody is, but also you can know a lot of things about that person, and it doesn’t matter where in the world that person may be.
There is so much more GPS systems information and a lot of things you can learn to understand and use a GPS system correctly and you can find all of them just by looking for us.
Browse our list of course schedules, course descriptions, locations, and the incredible low prices and discounts we have for you. We also have an extensive selection of books, software, and equipment for GPS users of all types.

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Saturday, November 7, 2009

The Fundamentals of GPS

What exactly is GPS?
By now, most of us have come into contact with some form of GPS.They are in our cars, sometimes on the dashboard and sometimes in the glove compartment; they're making their way into our cell phones and even being attached to children.Oh, the humanity!

GPS, or the Global Positioning System, is a satellite navigation system that provides positioning and clock time to the terrestrial user.The system consists of more than just satellites. While the satellites make up the space segment, the system also includes a control segment that monitors and maintains the satellites, as well as the user segment that gets to have all the fun.
When most people think of GPS, they think of the United States NAVSTAR (NAVigational System Time And Ranging) constellation.However, although GPS was the brainchild of the U.S.Department of Defense, other space-based satellite positioning systems are in existence or are slated for development, most notably the GLONASS system created by the former Soviet Union and the Galileo system recently approved for funding by the European Union.
Where, when, how and why
The U.S.Department of Defense created NAVSTAR to work optimally with a constellation of 24 satellites.NAVSTAR was declared fully functional on April 27, 1995 with a constellation of 24 Block II and Block IIA satellites.Unofficially, NAVSTAR became fully operational December 8, 1993 with a mix of Block II, IIA and the original concept validation Block I satellites; 28 Block II, IIA and IIR satellites are currently in orbit and operational.(Visit for more information.)
Each of the 28 NAVSTAR Space Vehicles (SVs) is equipped with two channels: L1 and L2.The L1 channel produces a Carrier Phase signal at 1575.42 MHz as well as a C/A and P(Y) code - all this jargon is explained below.The L2 channel produces a Carrier Phase signal of 1227.6 MHz , but only P(Y) Code.Currently, there are plans in progress to implement an additional civilian code on the L2 band as well as the creation of a brand new L5, but that is for another article.
Carrier Phase: GPS uses microwaves, and just like all light and radio waves, each signal has a unique frequency and wavelength.Although these waves do a great job of penetrating the atmosphere, they are still not capable of cooking a burrito from orbit.
C/A and the P(Y) Code: Binary data that is modulated or "superimposed" on the carrier signal is referred to as Code.Two main forms of code are used with NAVSTAR GPS: C/A or Coarse/Acquisition Code (also known as the civilian code), is modulated and repeated on the L1 wave every millisecond; the P-Code, or Precise Code, is modulated on both the L1 and L2 waves and is repeated every seven days.The (Y) code is a special form of P code used to protect against false transmissions; special hardware, available only to the U.S.government, must be used to decrypt the P(Y) code.
How do you like your data?
Not all GPS positions are created equal.Natural and man-made error sources can degrade the standalone accuracy of GPS by as much as 100 meters horizontally and 300 meters vertically. Fortunately, man-made errors (at least the deliberate ones) are relatively small at the present time.
Navigated or Autonomous Positioning is an uncorrected position calculated by the receiver using Code measurements.
How Code Works
While the GPS receiver is listening to the satellites, it is also downloading information about the satellites' orbit and trajectory.An almanac is transmitted every 12.5 minutes and contains approximate orbits for the constellation, as well as atmospheric modeling.The ephemeris is transmitted every 30 seconds and contains shorter, more precise trajectory data for a given satellite.
Philosophy and Math
Each satellite produces a unique code sequence of ones and zeroes.By matching the time difference of the code generated by the satellite's atomic clock and the user's clock (not so atomic), the GPS receiver is able to match the code and calculate a time difference. Based on the calculated time difference and known value of the speed of light, the distance between the SV and the receiver can be determined (speed of light multiplied by time.) Because of the clocks' discrepancy, the slowing of light through the atmosphere and slight inaccuracy of the transmitted almanac, we call this distance apseudorange.
The receiver position can then be calculated by intersecting distances from multiple satellites.Three satellites are required to determine a 2-dimensional position and four or more are necessary for 3D.
Differential Corrections
When we talk about differential or DGPS, we use the known position of one receiver to correct for the position of the unknown rover.Since we know the position of the satellite and the position of the known receiver, we can take the difference between the real range and the pseudorange to create a correction.We can then apply the pseudorange correction for each satellite to the unknown or rover receiver to calculate a better position.
Code Differential: We already covered the basics of calculating ranges using code techniques, so by using the same techniques to apply differential corrections to the ranges we can hope for a 30 centimeter-3 meter solution.
Phase Differential: Because phase data is all about the waves, the problem becomes figuring out just how many whole waves there really are. This is known as "Integer Ambiguity." After an autonomous position is calculated using code methods, clock errors can be negated by observing two satellites from two receivers (a method known as double differencing).Once the better approximation of the position is known, a statistical calculation of phase intersections from multiple satellites can be used to resolve ambiguous results.Because we know the length of the wavelength (e.g.19.4 cm for L1), we can add the number of wavelengths plus the fraction to create a distance that is not time dependent.
Post-Process Differential is done on a computer after the GPS measurements have been performed by the receivers on-site.In order to process this data, the user must have office software capable of calculating the differences, as well as a receiver that is capable of capturing raw data, which usually consists of a navigation file that includes satellite information and a file of observations with pseudoranges and their corresponding SVs.Although most receivers use a proprietary raw filetype, a generic format known as Receiver Independent Exchange Format (RINEX) was created to facilitate processing between different receivers and software packages.
Real-time Differential involves the use of a reference receiver, but differs from post-processing in that corrections are communicated instantaneously to the user or "rover."

Real-Time Code: There are currently several popular forms of RT-Code differential available to the consumer.
  1. Radio Beacon Correction: A land-based radio correction usually controlled by the Coast Guard and provided free of charge.(In the United States a National DGPS initiative has begun to provide double redundant beacon coverage across the 48 continental states.)
  2. atellite Corrections: A subscription-based service that provides the user with corrections from a geo-stationary satellite.
  3. WAAS EGNOS and MSAS: The Wide Area Augmentation System and its sister corrections in Europe and Japan are a new satellite-based differential that is free of charge, but still of questionable reliability. These systems are designed to provide a higher confidence level in autonomous GPS positioning for use in aviation.Unlike radio and satellite differential, WAAS corrects the atmospheric and orbital data so that autonomous calculations can better determine true position.
  4. User Defined: Higher end units can be used to create their own differential by employing two receivers (a reference and a rover) and communicating via radio, Internet, or cellular phone.

Real-Time Phase: Although similar methodologies are employed, RT-Phase (Real Time Kinematic) is far more complex than code and is usually performed on L1/L2 RTK-enabled GPS receivers.
Sources of Error: Finally, it is important to recognize the many error sources that GPS receivers that we as users must not only be aware of, but also correct.  For example:
  • Atmosphere: Ionospheric and Tropospheric refraction can delay the signal and cause ranging errors.(Think of a pencil in a glass of water.)
  • Multipath: Reflecting or bouncing signals not traveling directly to the antenna can cause ranging errors, e.g.buildings, tree trucks, canyons.
  • Satellite Geometry (Dilution of Precision or DOP): Bad satellite geometry can result in weak positional solutions.These DOPs can be separated into Vertical, Horizontal, Positional (3D) and Geometric (with time).
  • Selective Availability: The US government's ability to degrade positional accuracy by "dithering" or slightly altering the satellite clocks and by changing the broadcast ephemeris to report a slightly different satellite position.(Switched off on May 1, 2000, but can be reinstated at any time.)
  • Anti Spoofing: To prevent hostile outside sources from degrading the P-Code, the (Y) Code replaces the P Code, creating an encryption that can only be demodulated by special hardware.

While there is much more to GPS than covered in this article, we have hit the major hotspots of user level discussion.In future columns, we will build on this basic knowledge.
Greg Pendleton is a Licensed Land Surveyor and Product Manager for the GPS/GIS product area of the GIS & Mapping Division of Leica Geosystems, which specializes in creating hardware and software solutions for the acquisition and update of geographic database data via satellite positioning.

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