Electronic Tracker accuracy performance depends on the quality of the pseudorange

The differences between traditional cartographic “mapping” and Geographic Information Systems are increasingly becoming blurred. Conventional mapping as we generally think of it is quickly becoming absorbed into the purely digital world of GIS. And the Global Positioning System is helping to fuel this digital revolution. No longer is it necessary for cartographers and technicians to spend endless hours huddled over a scribing table to create a road map. Instead, with Personal GPS Tracking Device , a user can simply turn it on in kinematic/dynamic line-feature mode and take off down the street recording it as it goes, basically creating “instant” maps as fast as the road can be driven over.

The features described here, such as trees, telephone poles and fire hydrants, are very often not clearly visible on aerial photographs or maps. Surveyors could go out and survey each one, but it would take forever at phenomenal cost. Here Portable GPS Tracking Device truly comes into its own. Receivers with software de signed for GIS data collection can be taken to that representative tele phone pole, tire hydrant, or whatever, and, with only a few keystrokes, record all of the necessary information about them such as number of cross-pieces, number of transformers, condition, number of spigots, serial number and, of course, their precise geographic locations.

The accuracy with which a user receiver can determine its position or velocity, or synchronize to GPS system time, depends on a complicated interaction of various factors. In general, GPS accuracy performance depends on the quality of the pseudorange and carrier phase measurements as well as the broadcast navigation data. In addition, the fidelity of the underlying physical model that relates these parameters is relevant. For example, the accuracy to which the satellite clock offsets relative to GPS system time are known to the user, or the accuracy to which satellite-to-user propagation errors are compensated, are important. Relevant errors are induced by the control, space, and user segments.

The quality of the inertial sensors has a large role in the cost effectiveness of a navigation system. If 0.0001°/hour gyroscopes were to cost less than $100, GPS may not be needed today. But in actuality, inertial sensors are expensive, and a significant result of the integration of GPS with inertial sensors is the ability to use lower performing, more cost-effective sensors. It is the radius of a circle in which 50% of the projectiles are expected to fall within the given radius) When these systems are integrated with GPS, the lower curve dictates the performance of the integrated GPS/inertial (Smart Car Tracker ) system. Therefore, during operation of a navigation system when both GPS and inertial components are operational, the inertial navigation errors are bounded by the accuracy of the GPS solution. One significant contribution the GPS receiver makes to the operation of the inertial subsystem is the calibration of the inertial sensors. Note that mean radial error (MRE) is another indicator of delivery accuracy. (MRE is the mean of the miss distance of all projectiles.) Inertial instruments are specified to meet a turn-on to turn-on drift requirement.

More information at http://www.jimilab.com/ .

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