GPS Goto Control
Updated November 28, 2006

Download GPSGoto.ocx Visual Studio Control

The Goto Control conforms to the NMEA $..RMB sentence [Recommended Minimum Navigation Information] via the RMB Method. One must also use the Property cHeading to tell the control the current heading (denoted as "Track" on the control), or use the HDT Method via the NMEA sentence $..HDT [Heading True].

The indicator shows the desired direction to the waypoint; the compass card's top shows the heading (track) the boat is currently on. In this example, the boat is heading South-east (133 degrees), and the waypoint is at 120 degrees: we are off course.

At the bottom of the control shows the Cross Track error (XTE). If the Cross Track Error line is on the right side of the center line, one must steer left to get back on course. The maximum value for XTE is 9.9; the center line is the decimal point for the XTE number (in this example, 1.4 is the XTE number).

You may use several Properties to change the color of the indicator, the style of the indicator (line or dot), the font color, and the compass's back color.

The control includes the Arrived Event that is triggered when the RMB sentence notes that one's location is at, or very close to, the waypoint.

Note that the speed indicated is not the speed of the boat through the water; nor is it the speed of the boat over the ground--- it is the speed of the boat toward the waypoint. If the track (boat's heading) does not equal the waypoint's direction (bearing), the speed to the waypoint will be less than the boat's speed: if the heading and the bearing are both the same, only then will the speed indicate the boat's speed.

Events:

Arrived
Resize
GotoError

Methods:

HDT
RMB
BlankControl

Properties:

Heading
BorderStyle
Speed
Bearing
XTE
Waypoint
Distance
Night
Twilight
BackColor
FontColor
ErrorNumber
ErrorDescription
ScaleTicks
IndicatorColor
IndicatorStyle

Error Codes

0 - No Current Error
1 - RMB NMEA sentence appears malformed. It must start with $
2 - RMB NMEA sentence is not a valid $..RMB sentence.
3 - RMB Sentence $..RMB appears malformed.
4 - Indicator style must be 0 (needle) or 1 (dot).
5 - Tick scaling must be from 1% to 1,000%
6 - HDT NMEA sentence appears malformed. Must start with $--HDT.
7 - BorderStyle must be 0 or 1.
8 - Heading must be from 0 to 360.
9 - Bearing must be from 0 to 360.
10 - Speed must be 0 or greater.
11 - Waypoint name must be no more than 6 characters.
12 - Distance must be 0 or more.
13 - XTE must be from -9.9 to 9.9
NMEA Sage Home Page

The Banded Compass Control
The Compass Control
The North Biased Compass Control
The Goto Control
Course and Speed (Ground)
The Position Control
Engine RPM Control
The Rudder Control
The GPS Satellite Health Control
The GPS Satellite Elevation Control
Set and Drift control
The NMEA Talker Control
Depth and Water Temperature Control
The Wind Control
The Cross Track Alarm Control
The Pilot Control
Waypoint Plotter Control
Radar Control
Goto Simple Control