12-7  Section 12 Setting up Alerts 
 
 
 
 
12.6  Position Integrity Alert Generation 
Conditions 
[Operation procedure] 
Open the [Position Integrity] dialogue by performing the following menu operations. 
 
[Menu] button → Alert → Position Integrity 
In this dialogue, [Position monitor warning] issuing conditions and [HDOP Limit] can be set.   
 
12.6.1  Setting up the generation condition of the 
Position monitor warning 
Enter the following threshold value for issuing a position monitor warning.   
Position Difference Limit:   
The difference in distances when two GPS positions are compared at every second is used as a 
threshold value. Specify the difference in a range between 0.010 and 9.990 NM. 
 
[Position Difference Limit] functions when two GPS sytems are installed.   
 
Radius Limit (GPS): 
The radius of a monitoring circle having the predicted position of a GPS 1 sec later at the centre is 
used as a threshold value. If the position actually measured is not within the time monitoring circle 
specified in [Time Limit], it will be subjected to an alert. Specify the radius limit in a range between 10 
and 100 m. 
Radius Limit (DGPS): 
The radius of a monitoring circle having the predicted position of DGPS 1 sec later at the centre is used 
as a threshold value. If the position actually measured is not within the time monitoring circle specified 
in [Time Limit], it will be subjected to an alert. Specify the radius limit in a range between 10 and 100 m. 
Time Limit:   
The time during which the position actually measured by a GPS/DGPS deviates from the monitoring 
circle is used as a threshold value. The time limit can be specified in a range between 1 and 29 s. 
 
 
12.6.2  Setting up the HDOP exceeded caution 
generation condition 
Select HDOP threshold limit value in the [HDOP exceeded caution] combo box.   
Select either one of [4], [10] and [20].