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The navigation processor recognizes the direction of motion (forward or reverse) from the reverse signal.
Direction in which vehicle is pointing  
From the data of the gyrosensor and the sequence of the locations calculated with GPS the navigation 
processor the calculates the direction in which the vehicle is pointing (compass direction). 
The difference between calculated and actual distance traveled between two turning points is used for automatic 
recalibration of the tire circumference (required due to tire wear). 
Location finding errors during basic location finding  
Rolling backwards without the reverse gear engaged is evaluated as forward motion, and may lead to an error in 
the location finding. 
Rolling with the ignition switched off or vehicle transportation also falsify map matching. 
In both cases the deviation is automatically corrected by the navigation processor after receiving GPS data . 
Calibration  
Wheel calibration is not required following tire change. 
GLOBAL POSITIONING SYSTEM LOCATION FINDING, FUNCTION - GF82.61-P-3007C 
MODEL 163, 168, 170, 203.0 /2 /7, 208, 209.3 /4, 210 with CODE (353) Audio 30 APS  
Basic representation of the GPS location finding shown on model 210
 Global positioning system 
location finding, function GF82.61-P-3007GI
 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
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
me  
Saturday, October 02, 2010 3:30:05 PMPage 82 © 2006 Mitchell Repair Information Company, LLC.  
     
        
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Fig. 48: Identifying Global Positioning System Location Finding 
General information  
The global positioning system (GPS) is a location finding system established by the US Defense Department 
and is satellite supported. It is toll-free and is available throughout the world. A lot of satellites are located on 
different orbits. The GPS satellites constantly transmit time and position data. If data from at least 3 satellites is 
received it is possible to calculate the position of the receiver. 
GPS position finding is irreplaceable for journeys outside the digitized map area and after vehicle transport (e.g. 
train or ferry journeys and towing). A new GPS location finding (after interruption of satellite reception) can 
last several minutes (up to 20 minutes when first commissioning the equipment). 
Function  
The navigation processor that is integrated in the radio (A2) calculates the location of the vehicle and the 
accuracy of positioning from the satellite signals received and amplified. 
The following components can receive satellite data: 
Telephone and GPS roof antenna (A2/49) (model 163)  
GPS antenna (A2/49a2) (model 168, 208.3, 210)  
GPS rear antenna (A2/23a2) (model 170, 208.4)  
GPS antenna (A2/23) (model 203, 209)  
The actual calculation is essentially based on the measurement of the travel times of the signals sent 
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 accurate than the GPS location 
findin
g, the position currently calculated is corrected using GPS data.
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
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In addition, the vehicle's course of travel is determined with the aid of the sequence of the locations calculated 
with GPS. 
Possible interference when receiving GPS signals  
Since GPS operates in the GHz range (microwaves) and the signals are weak, reception interference can occur 
as the result of: 
atmospheric interference, e.g. weather, water vapor, fog  
multiple reception resulting from reflecting of signals, e.g. from building walls  
Signal shadows, e.g., in built-up areas, tunnel, in the proximity of higher buildings and trees  
GPS reception therefore necessitates a clear view of the sky. The location finding accuracy of the GPS system is 
100 m or better. 
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. 49: Identifying Global Positioning System Location Finding
 
General  
The global positioning system (GPS) is a satellite-supported location findin
g system. It is not subject to fees
 GPS/CTEL roof antenna 
location/task/design/ functionModels 163, 
168,208.3,210GF82.70-P-4111A
 Global positioning system antenna, 
location/ task/design/functionModels 170, 208.4GF82.61-P-4106A
  Models 203, 209.3GF82.61-P-4106E
  Model 209.4GF82.61-P-4107Q
 Antenna splitter, 
location/task/design/functionModel Series 163GF82.85-P-3107B
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
me  
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and is available worldwide . Presently there are 266 satellites on 6 different earth orbits. The GPSsatellites 
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,  GF82.70-P-4111A
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
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MAP-SUPPORTED LOCATION FINDING, FUNCTION - GF82.61-P-3008C 
MODEL 163, 168, 170, 203.0 /2 /7, 208, 209.3 /4, 210 with CODE (353) Audio 30 APS  
Basic representation of the map-supported location finding shown on model 210  
Map-supported location finding (map matching) is available only in the digitized area of the DVD map. 
A deviation can be recognized and corrected automatically by comparing the calculated position of the vehicle 
with the possible positions on the DVD map. 
Fig. 50: Identifying Map
-Supported Location Finding Function 
Function  
The position of the vehicle is continuously followed on the DVD map by the navigation processor. A number of 
alternative routes are calculated preliminarily in the digitized area of the DVD map. If the route driven varies 
from one of the possible routes, the position coordinates for basic location finding are corrected where 
necessary. 
 The navigation processor is integrated in the radio (A2). 
Loading the DVD map data  
The navigation processor has a read/write memory (RAM) for storing the DVD map data. However, this 
memory is not large enough to store the entire DVD map (currently approx. 10 %). For this reason, the 
navigation processor loads into the memory only the map data required for route guidance. 
Here, different storage methods are used depending on whether the destination is in the near vicinity of the 
vehicle or further away: 
The followin
g methods are used to store the data:
location/purpose/ 
design/function
 
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If the destination is in the near vicinity, a map area is loaded within a radius of approx. 100 km of the 
vehicle location ("Local area").  
For destinations further away, an area is selected surrounding the vehicle location, the destination and the 
concrete route to the destination ("Corridor formation").  
After storing the map data, the DVD with the map data can be taken out of the drive. Now, audio CDs can also 
be played. 
If the driver deviates too far from the calculated route during the course of navigation system and thereby leaves 
the map area stored in the navigation processor, it may be necessary to insert the DVD again in order to 
calculate a new route. The navigation processor requests this automatically. 
Location errors  
The errors are classified into 2 categories: 
Incorrect position indication between 2 driving instructions (may not occur more than once every 500 
km)  
Incorrect driving instruction (may not occur more than once every 1,000 km)  
MAP-SUPPORTED LOCATION FINDING, FUNCTION - GF82.61-P-3008GI 
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  
General  
Map-supported location finding is available only in the digitized area of the CD-ROM map. 
By comparing the calculated vehicle position with the CD-ROM map it is possible to recognize and 
automatically correct the deviation. 
Function  
The vehicle position is permanently followed by the navigation processor on the CD-ROM map. If the route 
deviates from the calculated route the position coordinates of the basic location finding are corrected if 
necessar
y. 
 Global positioning 
system location finding, 
function GF82.61-P-3007C
 
2001 Mercedes-Benz ML320 
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Fig. 51: Identifying Map-Supported Location Finding Function 
ROUTE CALCULATION, FUNCTION - GF82.61-P-3011E 
MODEL 163, 168, 170, 203.0 /2 /7, 208, 209.3 /4, 210 with CODE (353) Audio 30 APS  
Once the destination is entered into the radio (A2) the route is calculated by the integrated navigation processor 
and constantly updated. This can only be calculated within the digitalized map areas. The calculated route is the 
prerequisite of the destination guidance system. 
Route calculation, function  
The navigation processor calculates the route based on the entered destination and with the aid of the DVD map 
data while constantly finding the location. In the calculation, it takes into account the roads and attributes 
available on the DVD card and their attributes, such as one-way streets, bans on turns, road classes, etc. (where 
present). 
Additionally, it is possible for the operator to indicate how the route is to be calculated: 
Fastest route  
Shortest route  
Own adjustments  
In the event of "OWN ADJUSTMENTS", the following stretches can be blocked from the route calculation: 
FREEWAY  
 Basic location finding, 
function GF82.61-P-3006GI
 Global positioning system 
location finding, function GF82.61-P-3007GI
 Guidance, function GF82.61-P-3012GI
 Radio and navigation 
module, location/purpose/ 
design/function GF82.61-P-4109GI
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
me  
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FERRY  
TOLL  
After calculation of the route, the navigation processor makes up a list of the streets along the route. This route 
list is used for navigation. It can be displayed during navigation by pressing the "I" (INFO) and "RTE" (Route) 
buttons. 
Route updating  
If the driver deviates from the calculated route, a new route list is automatically calculated by the navigation 
processor. The current position and the direction of travel are taken into consideration, and the new route is 
optimized accordingly. This is accomplished without any message on the display. 
Circumventing traffic jams with "Traffic jam" menu key function  
After a traffic jam is reported on traffic radio and before reaching the affected section, a route can be calculated 
for driving around the traffic jam. For this purpose, activate the "Traffic jam" menu and enter the length of the 
traffic jam including the distance to the start of the traffic jam. 
The "Traffic jam" function is also available for Federal and State highways as well as for inner city areas. 
Trips outside the digitized map area  
If the vehicle leaves the digitized DVD map area (e.g. driving into a multi-level car park), then no route can be 
calculated or updated. "OFF ROAD" appears on the display. Upon leaving the map boundary, the display "OFF 
MAP" appears. 
Destinations which lie outside of the digitalized map area cannot be taken into consideration on calculation of 
the route. 
ROUTE CALCULATION, FUNCTION - GF82.61-P-3011GI 
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  
The route is calculated and updated continuously by the navigation processor after entering the destination on 
the radio and navigation module (A2/56) It can only be calculated within the digitized map area. The 
calculated route is the prerequisite of the guidance system . 
Route calculation  
The navigation processor calculates the route with the aid of the CD-ROMmap data, the entered destination 
 Destination guidance, 
function GF82.61-P-3012D
 
2001 Mercedes-Benz ML320 
1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis  
me  
Saturday, October 02, 2010 3:30:05 PMPage 89 © 2006 Mitchell Repair Information Company, LLC.