The Global Positioning System through time: the history of GPS

Blaise Mibeck

On May 7, 2009, the United States Government Accountability
Office (GAO) reported on the future of the Global Positioning
System (GPS). To put it lightly, the future does not look good.
At issue is the real possibility that “in 2010, as old
satellites begin to fail, the overall GPS constellation will
fall below the number of satellites required to provide the
level of GPS service that the U.S. government commits to.”

How did we get to this point? Most users of GPS are aware that
many satellites overhead provide the signals they use to map
their position or track their progress across town. How many
users know were GPS came from?

The first GPS was invented in 1610 by Galileo. It involved a
telescope and a table of eclipse times for Jupiter's moons.
Measuring the altitude of Polaris gave your latitude. By using
the eclipsing of Jupiter's moons as “ticks” from a global clock,
the time at home base could be determined (using the book of
tables). Comparing local time with the time at home base
produced longitude, or how far east or west you have gone.

Sure, it seems strange to refer to this as the first Global
Positioning System, but in principle today's GPS and that of
Galileo are identical. Each has a ground segment, a space
segment and a user. Each depends on time for the determination
of distance or location. More importantly, the initial
application was identical: navigation at sea. Galileo's GPS was
submitted to a challenge set by King Philip II of Spain in 1598.
Philip wanted a method for determining longitude (latitude was
easy) in order to reduce the risk of shipping goods from the New
World. It wasn't until 1761 that John Harrison's marine
chronometer became the first practical method for determining
longitude at sea.

Even with John Harrison's clock, the problem of position
determination persisted. This problem has always been highly
important to conducting war. The strategic implication of
knowing your position is multifaceted. Global positioning
affects the principles of warfare that deal with deployment of
mass, economy of force, maneuverability, unity of command,
surprise and simplicity. More important to land warfare is the
challenge of knowing your position despite Fog of War (FOW). FOW
describes the effect of battle field chaos that results in
disorganization, loss of central command and casualties due to
“friendly fire”. Naval warfare has its own FOW to contend with,
but also requires constant attention to one's location due to
the featureless nature of the ocean.

Radionavigation, developed in the 1920's, begins to resemble
today's GPS. Shore-based transmitters and radio direction
equipment aboard ships or planes made up this system. Two or
more stations were required for the navigator to triangulate his
position. This only worked in two dimensions (latitude and
longitude) and also encountered problems during bad weather.

Galileo's method, Harrison's clock and shoreline radio
transmitters represent the incremental advances needed to make
modern GPS. These inventions were motivated by trade and used
for conducting war.

To understand GPS today – to get the big picture – it is
important to realize that the problem it solves is ancient. By
seeing the important role global positioning has always played
in trade and war, today's user can better appreciate the system
they take for granted and the politics involved in its use.

How to Find the Best GPS System for Your Car

Mike Hamilton

There are many great GPS devices out there, but how do you
determine which is the best for use in your car? Of the major
brands there is Tom Tom, Magellan, and Garmin.

All of the major brands have something that you will or may find
useful or "cool". The trick is to find a GPS unit that does what
you need and has the most features that are useful to you. For
instance if you have an IPod ready sound system for your car
than a GPS system that plays MP3s is probably not a big deal and
you will, more than likely not want to pay extra for it.

One feature that you will want to be absolutely certain that
your GPS system has if you are going use it while driving is
menu simplicity. The last thing you want while motoring down the
road is to have to navigate a complex menu or the touch screen
is too difficult to hit just right to do just what you want.

The other major item to be on the lookout for is readability.
Some type of anti-glare screen is a must. You don't want to be
in urban traffic during rush hour and have a screen that is
absolutely worthless.

One other thing to check on is does the GPS system come with all
you need to make it work. If other accessories that you want or
need are not included you will want to price them before
purchasing the GPS system and it is too late. Some things that
may fall into this category are the mount and the power cord.
Some units come with a USB cord to charge it up with your
computer but not a cigarette lighter or AC cord.

A Personal GPS Locator Can Make Your Life Easier

John Taylor

A personal GPS locator is a handy little unit taking advantage
of assisted GPS technology for helping to determine its own
location as precise and reliable as possible. The location
information is normally triggered by requests from the internet
or from cell phones.

If you're making the request from the internet, you need to go
to a certain URL that the GPS locator vendor gives you and log
in. Then you will have to follow the instructions with normally
is nothing more that pushing a button or make a click on your
mouse and the real time location of you and your GPS locator
unit will be displayed on a map. You will be able to see your
neighborhood on this map and zoom it in and out and also scroll
it in the directions you want.

Using the cell phone alternative all you have to do is sending a
text-message to a number that your personal GPS locator's vendor
gives you will get the same as described above displayed on your
cell phone window.

Some of the GPS locator units offer personalized safety Zones.
What do I mean by this? A safety zone is a customized virtual
boundary around the location that you've chosen. For equipment
with this function you can normally be alerted via email and/or
text message when you enter or leave any safety zone you have
defined. Most GPS locator units allow you to create several such
zones and they can all be active simultaneously at any given
time.

Continuous Tracking

Dependent of what type of GPS locator you have you can set how
often the feature shall update your location, for example every
5 minutes or every 10 minutes, etc. The last updated time will
normally be displayed on the map or another place.

History of Locations

Location history can be useful; therefore many models are
equipped with this feature. The more expensive the model the
more detailed information you normally get. With this feature
you will have an overview of stored information so you can see
where your GPS locator has moved in a certain periode of time,
for example the past hour, day, week or even month. Models with
this feature will often display the information on a map, that
you are able manipulate as the real-time map, such as zooming
and scrolling.

Power Alerts

Depending on the model of your personal GPS locator, you can be
notified through email or text message when your GPS unit has
been powered off or when the battery's capacity level is at a
certain level, for example when there is 20 percent battery
power left.

As you may already know personal GPS locators are in the same
class as cell phones and other electronic communication devices
when it comes to aviation security, which means you can't use
them on airplanes.

Why A GPS Facilitated Vehicle Tracking Mechanism Can Ensure Peace Of Mind

John Mahoney

If you are part of a logistics or supply chain network then you
probably need a vehicle tracking system in place. This will
improve on your productivity and ensure peace of mind. Safety in
emergencies One of the best things about a vehicle tracking
mechanism is that you can ensure increased safety for both
yourself and your family members.

There is a special button installed in such GPS enabled systems
that you can press during emergencies. Whether it is a situation
of carjacking or some other issue, the respective operator of
the carrier can assist you. Even in situations where it maybe
harmful to talk to you directly, the operator can contact law
enforcement authorities on your behalf.

Help when stranded Our vehicles let us down when we least expect
it. If your vehicle is down and out because of some mechanical
issue then you just need to press a button and help will be at
hand. This is another beneficial aspect of vehicle tracking
systems.

This button is typically known as the ‘communication’ button
with almost all carriers. Being locked out If your kids have
locked you outside the vehicle, you can still be assured with a
vehicle tracking mechanism. All you need to do is contact the
call center of this carrier. Then the vehicle can be unlocked
easily. Losing your vehicle Lost sight of your vehicle? No
problem. With a vehicle tracking system, you can dial in to the
call center.

The operator will help to locate your vehicle and lights will
begin flashing on the vehicle. The horn will start honking too.
Thus, if you are lost in a crowded marketplace and need help
finding your vehicle, a vehicle tracking mechanism can be like a
virtual Godsend.

These operators will then locate your stolen vehicle and note
down the speed at the time of theft. They can then contact law
enforcement and police officials to recover the vehicle.
Logistics and tracking issues If you are part of the supply
chain and logistics segment then a vehicle tracking mechanism
can prove invaluable to you. Having such a system installed can
help you efficiently track movement of vehicles and
equipment.

Thus, you will know exactly how soon your vehicles will reach
their destination, thereby infusing more predictability into
your workflow. In addition, you can pinpoint any slackness on
the part of your employees by efficient tracking methods
introduced by a vehicle tracking installation. Better customer
service scores With the installation of a vehicle tracking
mechanism, you can up your customer satisfaction scores. Through
efficient tracking methods, you can guarantee fast shipping to
your customers – and live up to your promise. This will ensure
repeat sales for your business and more satisfied customers as
well.

IEEE 802.16: Broadband Wireless MAN Standard (WiMAX)

IEEE 802.16: Broadband Wireless MAN Standard (WiMAX)


An 802.16 wireless service provides a communications path between a subscriber site and a core network such as the public telephone network and the Internet. This wireless broadband access standard provides the missing link for the "last mile" connection in metropolitan area networks where DSL, Cable and other broadband access methods are not available or too expensive. The Wireless MAN technology is also branded as WiMAX.

IEEE 802.16 standards are concerned with the air interface between a subscriber's transceiver station and a base transceiver station. IEEE 802.16 is approved by th IEEE in June 2004. Three working groups have been chartered to produce standards: Task Group 1 of IEEE 802.16 developed a point-to-multipoint broadband wireless access standard for systems in the frequency range 10-66 GHz. The standard covers both the Media Access Control (MAC) and the physical (PHY) layers. Task groups a and b are jointly producing an amendment to extend the specification to cover both the licensed and unlicensed bands in the 2-11 GHz range.

IEEE 802.16 and WiMAX are designed as a complimentary technology to Wi-Fi and Bluetooth. The following table provides a quick comparison of 802.16a with to 802.11b:

Parameters	802.16a (WiMAX)	802.11 (WLAN)	802.15 (Bluetooth)
Frequency Band	2-11GHz	2.4GHz	Varies
Range	~31 miles	~100 meters	~10meters
Data transfer rate	70 Mbps	11 Mbps 55 Mbps	20Kbps 55 Mbps
Number of users	Thousands	Dozens	Dozens