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GPS applications - personal vehicle tracking devices

Январь 8th, 2016 by homesecuirtycameras and tagged , , ,

Understanding the right positions and directions of people and objects is a significant issue from the ancient eras to the present. In the past, people often launched a war in order to satisfy the craving for the dominating powers and spread their realms. In the recent, Global Satellite Positioning System (GPS) has become the one of most popular positioning technologies. GPS can provide users precise positioning information, no matter wherever that may present their own positions. The early GPS positioning technology has been widely used in military, marine use, until recently gradually applied into our daily life, e.g. automotive navigation, geodesy surveying, etc. In this chapter, the authors will briefly introduce some GPS issues including the origins of GPS, GPS system architecture, and related vehicle GPS tracking device applications.

The most driving purpose is to traverse to the destination safely, efficiently, and comfortably. Two types of approaches could achieve the goals, including the static and dynamic approaches. In the static aspect, vehicles use the static road and traffic information to navigate. Conversely, in the dynamic aspect, vehicles adopt the dynamic information instead. However, both of the two approaches first require getting the vehicle’s location and then map the position on an e-map. Thus, this chapter first introduces some important vehicle location determination algorithms: the dead reckoning and global position system algorithms, in which the precision of location technologies are compared. Then, the map-matching algorithm is described in detail. Finally, various vehicle navigation approaches are detailed, in which the important topics include: the navigation architecture, the navigation routing algorithm, and navigation applications.

The aim of tracking platform is to guide the vehicle along the optimal path from the starting point to destination. A reliable vehicle navigation system can reduce the traffic chaos in the city and improve the transportation delay. In order to achieve reliable vehicle navigation system, the detail system requirements, system analysis, and system architecture are shown in the chapter. Each component of vehicle navigation system is briefly illustrated, and the system communication is also described. They also present the architecture of the proposed vehicle navigation system, and show the difference of these systems. Therefore this chapter helps understanding the architecture of vehicle navigation system.

A smart GPS tracking device will tell you everything you want to know about the location of the vehicle, the speed at which it is traveling as well as the other conditions in that locality. It will give you a peace of mind as you now know clearly where the vehicle is. Moreover, you don’t have to worry constantly about calling up the driver every other minute to find out the status of the travel. There are some tracking systems that will also keep sending constant updates to your Smartphone. So, even if you are on the move and away from your laptop or desktop, you can still keep track of the vehicle.

Most electronic tracker work based on GPS, known as Global Positioning System. Hi-end systems even give you real time data imports. A good tracking system can keep track of multiple vehicles at the same time. So, if you are running a taxi service or is a college administrator keeping tracks of the many buses you have in your college fleet, you can keep track of all the vehicles using one system. When you are installing an online vehicle tracking system, you can be assured of the safety of your loved ones. Keep an eye them from afar with these high-tech tracking systems.

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Electronic tracking devices - about Multipath error

Январь 5th, 2016 by homesecuirtycameras and tagged , , ,

Multipath is a major error source for both the carrier-phase and pseudorange measurements. Multipath error occurs when the GPS ( personal GPS tracking devices ) signal arrives at the receiver antenna through different paths. These paths can be the direct line of sight signal and reflected signals from objects surrounding the receiver antenna. Multipath distorts the original signal through interference with the reflected signals at the GPS antenna. It affects both the carrier-phase and pseudorange measurements; however, its size is much larger in the pseudorange measurements. The size of the carrier-phase multipath can reach a maximum value of a quarter of a cycle. The pseudorange multipath can theoretically reach several tens of meters for the C/A-code measurements. However, with new advances in 32 Introduction to GPS receiver technology, actual pseudorange multipath is reduced dramatically. With these multipath-mitigation techniques, the pseudorange multipath error is reduced to several meters, even in a highly reflective environment.

Under the same environment, the presence of multipath errors can be verified using a day-to-day correlation of the estimated residuals. This is because the satellite-reflector-antenna geometry repeats every sidereal day. However, multipath errors in the undifferenced pseudorange measurements can be identified if dual-frequency observations are available. A good general multipath model is still not available, mainly because of the variant satellite-reflector-antenna geometry. There are, however, several options to reduce the effect of multipath. The straightforward option is to select an observation site with no reflecting objects in the vicinity of the receiver antenna. Another option to reduce the effect of multipath is to use a chock ring antenna (a chock ring device is a ground plane that has several concentric metal hoops, which attenuate the reflected signals). As the GPS signal is right-handed circularly polarized while the reflected signal is lefthanded, reducing the effect of multipath may also be achieved by using an antenna with a matching polarization to the GPS signal. The disadvantage of this option, however, is that the polarization of the multipath signal becomes right-handed again if it is reflected twice.

When a cell phone operator calls 911 to report emergency situation, it is desirable to locate the caller automatically. Often the caller is inside a building. If the building is equipped with a geolocation system, the caller’s location inside the building can be identified. The location of the building must also be identified. This combination of information is sent to the emergency unit receiving the call. Another approach is to use the GPS signal to locate the caller. However, inside a building the GPS ( GPS Tracking Device ) signal strength may be very weak.

One of the approaches is to use a GPS base station in the neighborhood to receive signals at normal strength. The GPS signals of normal strength are acquired and tracked. In other words, the initial phase of the C/A code, the carrier frequency, and the navigation data can all be obtained from the signals of normal strength. This information can be transmitted through the cell system to the cell phone users in the vicinity. The cell phone unit will include a GPS receiver. This GPS tracker can perform acquisition based on the received GPS information. Since the carrier frequency of the GPS is known only a very narrow frequency range need to be searched.

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