For users not familiar with magnetometer orientation principles, Cesium Sensor Active Zone Software (CSAZ) provides a quick “best fit” graphical solution for proper sensor orientation. The user inputs data including the geographical location of the survey (in decimal degrees), the true geographical heading of the survey, and the magnetometer type into the Mini-Wizard. After the data is entered, the program calculates the proper sensor orientation as well as information about the Earth’s magnetic field parameters including field strength (total field), inclination (angle of the Earth’s field relative to the surface of the Earth) and declination (angle between magnetic north and true or geographical north).
A cesium sensor is insensitive to magnetic fields in certain directions. In those locations, the sensor will be in what is known as the dead zone, or where sensor readings for the magnetic field are 0.00. This is due to the physics of the cesium sensor and can only be addressed by physically reorienting the sensor to the direction of the magnetic field. As shown in the figure below, the dead zone occurs if the magnetic field direction is within 15 degrees of the optical centerline of the sensor, or within 15 degrees of the plane perpendicular to that (the equatorial p lane).
If the survey is within 15 degrees of the equator or pole, the surveyor will need to mitigate the dead zone with proper sensor orientation. At latitudes between the dead zones, normal sensor installation allows users to survey in all compass headings and in all areas of the northern and southern magnetic hemispheres (approximately equal to the geographic hemispheres). At the equator or poles, the sensor is installed in a manner that allows the user to survey in the cardinal directions (N, E, S, VV) or at 45” to these cardinal directions, but not simultaneously in all directions.
Features and benefits
The software operates in two modes, Simple Solution and Advanced Operation.
- In Simple Solution, after entering latitude and longitude of the survey area (or clicking on the world map) and indicating the survey direction, the program provides an immediate graphical model of the properly oriented cesium sensor. The view can be rotated to provide various viewing angles of the orientation that provides maximum signal and best performance.
- In Advanced Mode, the user may vary the survey direction or the orientation of the sensor rotation and or tilt to observe sensor signal-noise-ratio as a function of orientation and survey direction.