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GPS Solution - GPS can measure the moving direction of a rigid object

Январь 12th, 2016 by homesecuirtycameras and tagged , , ,

Currently, GPS ( tracking platform ) is the best known and most used satellite positioning system. Over the past 30 to 40 years, several other positioning solutions have been deployed for use in various scenarios, based on various approaches, using infrared, ultrasound, image processing or electromagnetic waves. Positioning or location can be understood as the unambiguous placement of a certain individual or object with respect to a known reference point. This reference point is often assumed to be the center of the Earth coordinate system. In practice, Mobile Positioning and Tracking João Figueiras and Simone Frattasi the reference point can be any point on the Earth that is known to the system and which all the coordinates can relate to. Although the position itself is obviously a very important source of information, this position must be related to a specific time to be even more useful.

In particular, when we consider tracking systems, time information is a key necessity, not only for knowing the position of a certain device at a specific time, but also for inferring higher-order derivatives of the position, i.e., speed and acceleration. Thus, “tracking” is a method for estimating, as a function of time, the current position of a specific target. “Navigation” is a tracking solution that aims primarily at using position information in order to help users to move towards a desired destination. The sever has associated a relational database to store all information about users, devices, and sessions, and a spatial database to support the storage of spatial information, such as the GPS magnetic tracker fixes from all the mobile devices. The location-based application here also responds to queries sent from the “control station,” or main monitoring station, to obtain the GPS fixes of a particular user or group of users and display their positions in a graphical user interface in real time.

GPS also employs TOA ranging and threedimensional positioning model to calculate user position. The measurement of vehicle GPS tracking device positioning model is similar to two dimensional positioning model. Assume that each satellite transmits a unique ranging signal in space. A satellite has a clocks synchronized with others clocks built on other satellites. The clock synchronization and orbit plane of these satellites are monitored and controlled by the control segment (MCS).

GPS also can measure the moving orientation (direction) of a rigid object, e.g., a vessel, an aircraft, etc. A GPS receiver also has a clock synchronized to GPS system time. Ranging signals transmitted from GPS satellites contain time information. It enables the receiver to measure the propagation time of the ranging signal left the satellite based on satellite clock time. We can find that the user position would be at two possible points, and only one of the points is the correct user position. For the user position, it is generally locates on the surface of the earth. Therefore, the lower one of two points will be the true position. In order to measure the more accurate user position, the fourth satellite will be applied to calculate and fix the user’s altitude. In addition GPS can determine the user velocity. The most popular used method is based on estimating the Doppler frequency of the received GPS signals.

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GPS tracking device are available as handheld portables

Январь 7th, 2016 by homesecuirtycameras and tagged , , ,

GPS tracker mini are available as handheld portables, as stand- alone bracket mounted or in - dash models, and as “ black boxes ” combined with sonar devices. Sportfi shing boaters use GPS to get to and from selected locations and to determine the exact location of important fi shing grounds. The additional value to anglers is in pinpointing places to fish, schools of fish, or significant underwater structures, and being able to return to them unerringly. In some instances there is great value to pinpointing the specifi c part of an area to fish such as the riprap near a submerged wreck. The locations saved in GPS receivers are called waypoints. Once a waypoint has been saved, an angler can return to it at any time. Saving is most commonly done by pressing a button while the unit is located at the waypoint ’ s position; the position can also be saved by entering its latitude and longitude coordinates through the keypad.

These coordinates are important because with the lat/lon coordinates you can fi nd a place that you have never been to; the coordinates can be given to you, or you can take them off a good navigational chart. It’s a good idea to record waypoint information in a logbook as a backup, in case the unit is lost, stolen, or breaks down. You can reenter the waypoints manually after fixing or replacing your unit or acquiring another. Integrating with a personal computer will allow you to store appropriate information as well as plan trips.

No detailed study of vehicle GPS locator is complete without a study of the most commonly used protocol for communication between the GPS and other devices. Even if you have no intentions of writing applications that process or work with GPS data, and instead plan on using only readymade applications. Therefore, anglers who troll use various other instruments, referred to as speed gauges, speed sensors, or speed indicators, to accomplish this. These include electronic instruments fi tted with a paddlewheel, which is secured to the boat transom flush to the hull; GPS navigational devices; and non - electronic drag - weight gauges, which measure speed relative to markings on a plate. Additionally, there are devices, attached to downrigger weights, that measure via paddlewheel the speed of the lure at the depth of a downrigger weight. This is sometimes different than surface speed. The most accurate speed gauge is a GPS unit, which measures distance traveled over time. If you ’ ve used an automobile navigator you know how reliable this system is at determining speed. Most larger sportfishing boats are equipped with some type of vehicle GPS tracking systems, often in combination with a sonar device, and when trolling, the speed is always known and displayed.

Dustproof and Waterproof Car tracking GPS is a powerful and easy-to-use GPS tracker specially designed for motorcycle, electromobile and common vehicles. Operating voltage is from 7.5-90 VDC, which would be suitable for every vehicle on the road.  With GSM+GPRS+GPS technology, the device can easily achieve fast and accurate positioning. IP65 standard protects the device from rain and dust. Vibration detect, SOS button, geo-fence alarm and remote cut off power protects the vehicle in 360 degree.

Remote control ( Remote cut Off power/electricity )

Send SMS to the device to cut off the vehicle engine and circuit when someone startup the vehicle illegally in remotely.

Low voltage protection for battery

When your vehicle is laid-up, it will be in low battery to protect your vehicle.

Dustproof and Waterproof

It is waterproof and dustproof so that it can be protected well for a long time.

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GPS tracking solutions —— basic knowledge about GPS system

Декабрь 28th, 2015 by homesecuirtycameras and tagged , , ,

Today, GPS (  GPS for vehicle ) is causing a renaissance of the navigation, surveying and mapping professions and may, within only a few years, completely replace conventional methods of transportation navigation and land surveying. The uses and implications of the GPS system are yet to be fully realized, and new applications are being found at an ever-increasing rate. There are three parts to the GPS system: the satellite segment, the user segment, and the control segment.

Control segment

This part keeps the whole system running smoothly. Satellites need to be kept in their proper orbits and their signal transmissions kept up-to-date. The Air Force operates a series of five ground stations around the globe, typically at exotic tropical locations: Hawaii, Ascension Island, Diego Garcia, Kwajalein, and the decidedly nontropical master station in Colorado Springs. You’ll probably never think about the control segment, but without it, the entire system would quickly fall into disrepair.

Satellite segment

Satellites are the heart of the Global Positioning System. They broadcast the signals your receiver uses to determine your position. At least 24 satellites are in operation at all times, each orbiting the earth every 12 hours (or 11 hours and 58 minutes, if you want to be precise). Their orbits are designed so that, theoretically, at least 6 and as many as 12 satellites are above the horizon virtually all the time, regardless of where you are. “Theoretically” is the key word here—the satellite signals don’t travel through mountains, buildings, people, or heavy tree cover, so unless you’re on a flat plain or body of water, some signals probably will be blocked. Since your receiver must lock onto at least four satellites to accurately determine its position, you may have to move around to get better reception. (By the way, it’s a little-known fact that all GPS satellites perform a second duty: Each includes an X-ray detector that lets the U.S. government monitor nuclear explosions anywhere in the world.)

User segment

Your handheld receiver makes up the user segment. There’s a lot of power inside that little package. Not only does it contain a sensitive receiver capable of detecting signals less than a quadrillionth the power of a light bulb, it also includes a powerful computer that converts the raw data into such useful information as your position and speed. A GPS magnetic tracker doesn’t include any kind of transmitter, meaning it is a passive positioning system—you can determine your own position, but there’s no way for anyone else to use it to track you.

However, accuracy can be improved by combining the electronic tracker with a Differential GPS (or DGPS) receiver, which can operate from several possible sources to help reduce some of the sources of errors described above. Differential GPS works by placing a GPS receiver (called a reference station) at a known location. Since the reference station knows its exact location, it can detennine the errors in the satellite signals. It does this by measuring the ranges to each satellite using the signals received and comparing these measured ranges to the actual ranges calculated from its known position. The difference between the measured and calculated range.

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