Global positioning system location finding, function - GF82.61-P-3007GI

MODEL 163 as of 1.9.01 with CODE (522) Modular control system (MCS) radio USA with CODE (357) Navigation system - additional unit with CODE (818b) Single CD player - additional unit with CODE (491) U.S. version

Fig 1: Identifying Global Positioning System Location Finding

General

The global positioning system (GPS) is a satellite-supported location finding system. It is not subject to fees and is available worldwide . Presently there are 266 satellites on 6 different earth orbits. The GPS satellites permanently transmit time and position data. If data from a minimum of 3 satellites is received (with two-dimensional location finding) it is possible to calculate the position of the receiver.

The GPS location finding is particularly important when driving outside of the digitized map area and following vehicle transport (e.g. train, ferry or towing).

A repeated GPS location finding (following satellite reception interruption) can take several minutes (when unit is initially started up to 20 min .).

GPS map matching function

The navigation processor calculates the location of the vehicle and the accuracy of positioning from the satellite signals received and amplified by the GPS antenna (A2/49) . The current calculation is based primarily on the measurement of the transmission times for the signals transmitted synchronously by the various satellites. Here, an important prerequisite is that the satellite and receiver clocks are synchronized . For this purpose, the receiver has an automatic time correction feature which again is possible with the aid of the satellite signals. If the navigation processor determines that the basic location finding is less precise than the GPS location finding, the currently calculated position is corrected with the aid of the GPS data .

Moreover, the vehicle route is determined from the location sequence calculated with GPS .

Approx. 50 new GPS location finding calculations are performed each minute.

Possible interference when receiving GPS signals

Since GPS operates in the GHz (microwave) range and the signals are weak, reception interferences can occur from

atmospheric interferences, e.g. weather, water vapor, fog,
multiple path reception due to signal reflections, e.g. from building walls
Signal shadows, e.g. in built-up areas, tunnels, high buildings, trees

A free view of the sky is therefore necessary for GPS reception The location finding accuracy is approx. 100 m or better .

	Basic location finding, function		GF82.61-P-3006GI
	Map-supported location finding, function		GF82.61-P-3008GI
	Guidance, function		GF82.61-P-3012GI
	Radio and navigation module, location/purpose/ design/function		GF82.61-P-4109GI
	GPS roof antenna/telephone, location/purpose/ design/function		GF82.70-P-4111A