The SIS_OT_GPS object provides a number of properties which can either be read or modified. Use the GetFlt/GetInt/GetStr methods to read these properties, and the SetFlt/SetInt/SetStr methods to modify those properties which are not read-only.
Has Fix: _bHasFix&:
Does SIS currently have sufficient satellite data input to establish a geographical fix? This data may be dynamically received from a GPS receiver, or from a previously recorded log file.
Read only
Logging: _bLogging&
Is SIS currently recording a log file from GPS input?
Read only
Replaying: _bReplaying&
Is SIS currently replaying an existing log file?
Read only
Replay Paused: _bReplayPaused&
Is a currently replaying log file paused?
Read only
Data Rate: _dataRate&
The interval in milliseconds at which data is to be read from a GPS device.
PDOP Mask: _PDOPMask#
The value to be used as the Position Dilution of Precision confidence level below which positions are deemed too inaccurate. See below for further detail about PDOP.
Satellites In View: _nSatellitesInView&
The number of satellites in view in the current GPS input.
Read only
Satellites In Fix: _nSatellitesInFix&
The number of satellites in fix in the current GPS input. These are the satellites contributing to the calculation of the current position.
Read only
Latitude: _latitude#
The latitude of the current GPS position.
Read only
Longitude: _longitude#
The longitude of the current GPS position.
Read only
Altitude: _altitude#
The altitude of the current position.
Read only
UTC Time: _UTCTime$
The Coordinated Universal Time (UTC) at which the GPS string is being received, or was received, in the case of replaying a log file (see Note below).
Read only
UTC Date: _UTCDate$
The date (UTC) at which the GPS string is being received, or was received, in the case of replaying a log file
Read only
Speed: _speed#
The travel speed over the ground in knots of the GPS device at the time of reading the data
Read only
Track Angle: _trackAngle#
The travel direction in degrees relative to True North of the GPS device at the time of reading the data.
Read only
HDOP: _HDOP#
The Horizontal Dilution of Precision value of the current GPS input.
PDOP: _PDOP#
The Position Dilution of Precision value of the current GPS input.
The values for PDOP are as follows:
DOP: 1
Rating: Ideal
Description: This is the highest possible confidence level, to be used for applications demanding the highest possible precision at all times.
DOP: 2-3
Rating: Excellent
Description: At this confidence level, positional measurements are considered accurate enough to meet all but the most sensitive applications.
DOP: 4-6
Rating: Good
Description: This represents a level that marks the minimum appropriate for making business decisions. Positional measurements could be used to make reliable in-route navigation suggestions to the user.
DOP: 7–8
Rating: Moderate
Description: Moderate Positional measurements could be used for calculations, but the fix quality could still be improved. A more open view of the sky is recommended.
DOP: 9–20
Rating: Fair
Description: This represents a low confidence level. Positional measurements should be discarded or used only to indicate a very rough estimate of the current location.
DOP: 21–50
Rating: Poor
Description: At this level, measurements are inaccurate by half a football field’s length or more and should be discarded.
VDOP: _VDOP#
The Vertical Dilution of Precision value of the current GPS input.
datum: _datum$
The geoid datum to be used in calculating positions from the GPS input (normally OCG.WGS_1984)
Note: Coordinated Universal Time (UTC), maintained by the Bureau International des Poids et Mesures (BIPM), is the time scale that forms the basis for the coordinated dissemination of standard frequencies and time signals. The UTC scale is adjusted by the insertion of leap seconds to ensure approximate agreement with the time derived from the rotation of the Earth. These leap seconds are inserted on the advice of the International Earth Rotation and Reference Systems Service (IERS).
Send comments on this topic.
Click to return to www.cadcorp.com
© Copyright 2000-2017 Computer Aided Development Corporation Limited (Cadcorp).