JIMI Electronic

When you start using a GPS Tracking Devices , you’ll soon discover that it’s pretty numbers-oriented. There’s time, speed, distance, altitude, and (of course) the location coordinates. But quite often you’ll want names to go with those numbers. Or you might need to convert those coordinate numbers into another format. Read here to discover how to locate places by their names and get their coordinates (and other information) and how to easily convert coordinates from one coordinate system to another. Finding Your Way with Online Gazetteers Sometimes you need a little bit more information about a location. You know a place name, but you don’t know exactly where the place is  located. You’ve heard about a place but don’t know whether it’s a mountain peak,  a river, or a town. You generally know where a place is, but you need the exact latitude and longitude or Universal Transverse Mercator (UTM) coordinates. In these cases, you can turn to a gazett...

There are many parameters used by the industry to assess the performance of a GPS receiver, and to evaluate the relative performance of comparable receivers. The most common parameters being used to evaluate GPS receiver performance include positioning and timing accuracy, time-to-first-fix, reacquisition time, and receiver sensitivity. Positioning and timing accuracy The most obvious of these parameters is positioning accuracy – how accurate are the positions calculated by an autonomous GPS receiver, based on the number of satellites that can be seen by that receiver? This is typically measured by performing a mapmatching test, where positions calculated by a receiver for landmarks on a map are compared to their known positions. This is a standard test that is often used to compare the accuracy of multiple GPS receivers simultaneously. When the S/A feature was still enabled, the accuracy of the SPS signal served as the baseline for positioning accuracy for commercial GPS rece...

In order to design and build a GPS receiver, the developer must understand the basic functional blocks that comprise the device, and the underlying hardware and software necessary to implement the desired capabilities. The sections below describe the main functional blocks of a GPS receiver, and the types of solutions that are either available today or in development to provide that functionality. The demand for the integration of positioning technology into smaller devices is challenging antenna development. The industry is already pushing for smaller antennas for applications such as a wristwatch with integrated GPS, which is smaller than most patch antennas available today. Another demand is for dual-purpose antennas that do double duty in wireless communication devices, such as in a mobile telephone with an integrated GPS receiver. Inevitably, the future will bring smaller and more flexible antennas for  GPS Tracking Device  . The function of the downconverter is to s...

Server-assisted GPS positioning Server-assisted GPS is a positioning technique that can be used to achieve highly accurate positioning in obstructed environments. This technique requires a special infrastructure that includes a location server, a reference receiver in the mobile unit, and a two-way communication link between the two, and is best suited for applications where location information needs to be available on demand, or only on an infrequent basis, and the processing power available in the mobile unit for calculating position is minimal. In a server-assisted GPS system, the location server transmits satellite information to the mobile unit, providing the reference receiver with a list of satellites that are currently in view. The mobile unit uses this satellite view information to collect a snapshot of transmitted data from the relevant satellites, and from this calculates the pseudorange information. This effectively eliminates the time and processing power require...

Most, not all, GPS surveying relies on the idea of differential positioning. The modeof a base or reference receiver at a known location logging data at the same time as a receiver at an unknown location together provide the fundamental info rmation for the determination of accurate coordinates. While this basic approach remains today, the majority of electronic tracking device surveying is not done in the static postprocessed mode just described. Postprocessing is most often applied to control work. Now, the most commonly used methods utilize receivers on reference stations that provide correction signals to the end user via a data link sometimes over the Internet, radio signal, or cell phone and often in real-time. In this category of GPS surveying work there is sometimes a distinction made between code-based, DGPS, and carrier based, RTK, solutions. In fact, most systems use a combination of code and carrier measurements so the distinction is more a matter of emphasis rather than...

The Federal Geodetic Control Committee (FGCC) has written provisional accuracy standards for GPS relative positioning techniques. The older standards of first, second, and third order are classified under the group C in the new scheme. In the past, the cost of achieving first-order accuracy was considered beyond the reach of most conventional surveyors. Besides, surveyors often said that such results were far in excess of their needs anyway. The burden of the equipment, techniques, and planning that is required to reach its 2σ relative error ratio of 1 part in 100,000 was something most surveyors were happy to leave to government agencies. But the FGCC’s proposed new standards of B, A, and AA are respectively 10, 100, and 1000 times more accurate than the old first-order. The attainment of these accuracies does not require corresponding 10-, 100-, and 1000-fold increases in equipment, training, personnel, or effort. They are now well within the reach of private GPS surveyors both econo...