gpstrack - GPS Track Calculator

The following form calculates the horizontal and vertical track as well as the distance between two GPS points.

GPS position of your antenna Latitude (N): Longitude (E): Altitude: Orientation of your antenna Heading: Pitch: Roll: GPS position of the peer antenna Latitude (N): Longitude (E): Altitude:

A few hints: Type negative latitude angles for points on the southern hemisphere. Type negative longitude angles for points in the west. Zero heading means that your antenna mount is facing north.

Description

This script is intended for calculating the direction of an antenna that has to point towards a known GPS position (the peer antenna). To calculate that, 9 parameters are necessary:

• The GPS position of your antenna: latitude, longitude and altitude (3 parameters).
• The orientation of your antenna mount: heading, pitch and roll (3 parameters).
• The GPS position of the peer antenna: latitude, longitude and altitude (3 parameters).

If heading, pitch and roll are 0, the antenna is assumed to be mounted on a flat surface (levelled) with its main axis pointing north. I.e. if both the horizontal and the vertical angles are 0 degrees, the antenna points north; if the vertical angle is +90 degrees, the antenna points straight up to the sky.

Heading (yaw) then defines the horizontal deflection from that position. Pitch and roll define the vertical deflection. For a better explanation of pitch, roll and yaw, you may want to have a look at the Flight dynamics article on Wikipedia.

The result gives you the horizontal and the vertical angle. For the horizontal angle, the antenna is assumed to turn in the mathematical sense (counter-clockwise).

A Simple Experiment

To understand how this script works, do the following experiment:

• Enter your current GPS position in the GPS Position of your antenna fields.
• Enter the GPS position of the point you want to watch in the GPS position of the peer antenna fields.
• Make sure that the fields Heading, Pitch and Roll are all 0.
• Click Calculate.

You get three results: the distance to the peer antenna, the horizontal angle and the vertical angle.

• Turn yourself towards north.
• Look at the calculated horizontal angle and turn that many degrees to your left.
• Look at the calculated vertical angle and turn your head that many degrees up. (If the angle is negative, you turn your head down.)

You are now looking towards your peer antenna.