Page 58 957 Operator’s Manual, Rev. BChapter 5 - Determining Your PositionUsing loran This section explains how you can use the 957 to navigateusing displayed loran coordinates if the 957 is connected to anloran receiver (such as the Northstar 800). If you don’t plan touse loran, you can skip this section.Selecting anddisplaying loranTo display loran time differences (TDs) from a connected loranreceiver:1. Press the STAR key to display the OPTIONS/SERVICEINFO screen.2. Press the NAVIGATION OPTIONS menu key, then selectthe NAVIGATION SOURCE field.3. Press the EDIT menu key, then press the CURSOR PAD todisplay EXTERNAL LRN as the position source.4. Press the ENTER key, then press the RETURN menu key.5. Press the CHART key to display the GPS POSITION screen.6. Press the CHECK LORAN key to display the LORAN POSI-TION screen.TOO FEW CORRECTIONS DGPS is off because not enough satellites with corrections areavailable.POOR BCN DOP DGPS is off because the satellites with corrections have poorgeometry (DOPis an acronym for Dilution Of Precision).OLD CORRECTIONS DGPS is on, but the current corrections are older than the timeoutyou’ve set in the receiver options (see ”Choosing a DGPS correc-tions time-out” starting on page 150).DGPS IN USE/OK DGPS is on and the corrections are current.UNKNOWN An unknown status code has been received from the GPS receiver.Table 4: DGPS status messages (continued)DGPS message Meaning
