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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How GPS tracker work - Time is of the Essence

Декабрь 25th, 2015 by homesecuirtycameras and tagged , ,

With progressive development in technology in recent years, one can relish the prime advantages of the various innovative software solutions such as field service tracking software. A lot of operational costs can be reduced using this software to improve the ROI. From various records, it is also proven that many industries have saved up to 30% using the field service tracking system. The best thing about using this software is that, it can be accessed from computers, smart phones or tablets. In addition to these types of GPS receivers, larger and less portable models are used in airplanes, boats, and commercial vehicles. The U.S. government and military uses restricted-use GPS units, and expensive receivers are used for surveying. Although some of these vehicle GPS tracking devices are discussed briefly, don’t expect to find out as much about them as the land and auto consumer models. I tell you what questions to ask when selecting a GPS receiver and give you some hints on which features are best for different activities. You can apply these questions and selection criteria to pretty much any GPS 3G tracker for Car to pick the right model for you.

In a conventional Personal GPS tracker the information, such as carrier frequency and initial C/A code phase obtained from the acquisition, can be used to track a signal. The navigation data phase transition can be found through the tracking program. For a weak signal it is difficult to determine the exact location of the navigation data transition from the tracking program. In order to process the data efficiently, the exact location of the navigation data phase transition is needed such that one can start to process the data every 20 ms. Thus in this section the determination of the location of the navigation phase transition is discussed. In general, it is easier to determine whether there is an existence of data transition than to determine the exact location of a data transition.

Even though the vehicle GPS tracking device knows the precise location of the satellites in space, it still needs to know how far away the satellites are (the distance)so it can determine its position on Earth. There is a simple formula that tells the receiver how far the satellites are (the distance)so it can determine its position on Earth.  There is a simple formula that tells the receiver how far it is from each satellite:Your distance from a given satellite object equals the velocity of the transmitted signal multiplied by the time it takes the signal to reach you (Velocity x Travel Time = Distance).

The satellites orbit at an altitude of approximately 20,200 kilometers, or about half the altitude of a geostationary satellite. A geostationary satellite, orbiting at about 40,000 kilometers altitude, circles the Earth every 24 hours, the same time period that the Earth takes to complete one full rotation (one day). Therefore, a geostationary satellite always remains over the same spot on the Earth (thus “geostationary”), essentially following that “spot” on the surface as the Earth rotates. The GPS satellites, at one-half that altitude, complete one orbit every 11 hours, 58 minutes (its “orbital period”). Since the Earth is rotating underneath the orbiting satellites, any given satellite’s orbit slowly “moves” slightly westward with each rotation.

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Essential applications for electronic tracker

Декабрь 22nd, 2015 by homesecuirtycameras and tagged , ,

motorcycle GPS tracker are designed with many built-in features but only a few are essential for wilderness navigation. Any feature that requires the tracker to stay switched on for prolonged periods should be used sparingly as conserving battery power is an important consideration, especially in cold weather.

Not all GPS receivers can display maps. Lower-cost models (typically under $150) or GPS receivers with very small screens usually don’t support maps. If you already own a GPS receiver, make sure that it’s compatible with the map software you’re interested in using. Manufacturer Web sites are pretty good about listing product compatibility. The same holds true if you’re shopping for a new GPS receiver.

You can use only proprietary products (made by the same company that manufactures your GPS tracker). Admittedly, I’m belaboring this point, but a fair number of novice GPS users think that they can load just about any map on their new GPS tracker, which isn’t the case.

Don’t expect the level of detail in a GPS map to match paper maps. In order to maximize memory space, Magnetic GPS use vector maps (created with lines and shapes) instead of raster maps (scanned paper maps). And because a GPS tracker has a fairly small screen to display a map, don’t expect the map on your GPS tracker to appear as an identical version of your favorite paper map. Until tracking devices for people incorporate science-fictionlike, holographic projection systems where a map appears in midair (and I’m not holding my breath), viewing a paper map will always be easier and more effective than staring at a map on a GPS tracker.

Determining your position

The ability to pinpoint your position during any type of weather almost anywhere on Earth is the most basic application of a waterproof tracking devices. Just switch on the tracker and wait for a position fix. Your position can be displayed as a grid number, a geographic coordinate, or a point on a built-in digital map. With signals from a minimum of four satellites, the tracker will display your elevation.

Storing a position as a waypoint

A waypoint is simply a named set of coordinates representing a position. Once your tracker has acquired a position fix, you can store the position in the tracker’s memory as a waypoint. This is very useful for finding your way back to the position. You could also give the waypoint’s coordinates to someone else, who could then find the waypoint with his or her own tracker.

Inserting a waypoint

You can manually key a position into your tracker’s memory as a waypoint without ever having set foot at that location. The coordinates for the waypoint could be obtained from a printed map or from someone else who has previously been there. With a computer, you can insert waypoints electronically into a GPS tracker from a digital map.

Navigating toward a waypoint

Finding your way toward a stored waypoint is the essence of GPS navigation. With waypoints stored in its memory, switch on the tracker and let it acquire a position fix. With a few keystrokes, the tracker will display the distance and bearing toward any stored waypoint. There are two primary ways to navigate toward a stored waypoint: (1) using the tracker by itself, or (2) using it together with a compass. By itself, the tracker must be switched on continuously. With a compass, the tracker requires only intermittent use with most of the navigating done by the compass.

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