a method of obtaining greatly enhanced precision from GPS navigation. Generally involves a correction signal transmitted from a reference GPS receiver, the exact location of which is known, (called the base station) to the GPS receiver being used to take measurements (called the 'rover')
A mathematical method of correcting inaccuracies in GPS data during post-processing. Differential correction compares the positions recorded by a mobile GPS unit with those taken at the same time at a nearby base station with a fixed location. The idea is that whatever variations occur in the signals received by the mobile device will also have occurred at the base station. Since the base station knows its exact position, any variances in the positions recorded by the base station can be reduced mathematically, or corrected. Whenever we apply this same correction to positions recorded at the same moment by a mobile GPS unit, we increase the accuracy of the position, often on the sub-meter level.
A technique used to improve GPS accuracy. Differential correction signals remove or reduce errors associated with atmospheric effects and other positioning errors. The correction signal can be land-based or satellite-based. Common sources of differential correction include WAAS, Omnistar, and Coast Guard Beacon.
differential correction is the method used, via base station, to calculate error vectors that coincide with field data to correct the field data error
A technique for improving the accuracy of GPS positioning. Errors introduced by selective availability are recorded by a stationary receiver at a well-defined location. Errors detected by the stationary receiver can be used to cancel out errors recorded at the same time by a mobile receiver in a different location.
Corrects the GPS signal to make it more accurate. An uncorrected signal will be accurate to within 50 yards. A corrected signal can be accurate to within 5 to 10 feet. To correct the signal, a second GPS receiver is placed in a fixed, known location. This location is used to calculate the current error in the GPS signal. These data are then transmitted to a nearby tractor, combine, or pickup, which corrects its own position. There are four ways to transmit the correction signal from the base station to the farm implement. One is a dedicated transmitter that is located on an existing tower (Mobile Data, or SATLOC), which has a range of 30 to 40 miles. Another way is to use a separate, private corporation satellite to send the corrected signal (SATLOC), which has a range of 1,000 miles. A third way is to 'piggyback' the correction signal on a commercial FM radio station frequency (DCI, or ACCQPOINT), which also has a range of 30 to 40 miles. The fourth way is to use AGNAV, a new technology that does not need a differential correction.
A technique used in DGPS. Differential corrections may be used in real-time or later, with post-processing techniques. Real-time corrections can be transmitted by radio link. The U. S. Coast Guard maintains a network of differential monitors and transmits DGPS corrections over radiobeacons covering much of the U. S. coastline. DGPS corrections are often transmitted in a standard format specified by the Radio Technical Commission Marine (RTCM). Corrections can be recorded for post processing. Many public and private agencies record DGPS corrections for distribution by electronic means.
A process for canceling out man-made and natural errors in the GPS signal. Requires the use of another GPS receiver set up on a position with known location. The receiver on the known location computes its location with the GPS satellite data and compares this position with the known value for its actual, known, position. This difference (hence differential) is the error in the transmitted GPS signal. The differential value is then used for correcting, either in real-time or during post processing, the positions collected by other GPS receivers during the same time period, observing the same satellites.
correction of a GPS signal that is used to improve its accuracy (to less than 100 m/~330 ft) big using a stationary GPS receiver whose location is know. The second receiver computes the error in signal by comparing the true distance from the satellites to the GPS measured distance.
A technique for overcoming GPS position determination errors; GPS receivers are placed at precisely identified control locations to measure the difference between indicated GPS positions versus actual positions.
Using either GPS positions collected from a base station (located on a known position) simultaneously or RTCM broadcasts to increase the accuracy of your position information.
