This value is the horizontal towing distance of the sensor (magnetometer fish) from the boat’s GPS antenna, within a range of (-) eleven feet in front of the antenna to 392 feet behind the antenna. For the two smallest scale modes, these distances are limited to 196 feet and 98 feet.  MagSurvey relies on this layback value and on Track-Over-Ground (TOG) information from the GPS to determine the recorded values of sensor latitude and longitude. It is important that the sensor be as close to directly behind the boat’s track as is possible whenever LOGGING is enabled. Best results are obtained by towing the sensor as close to the boat as can be done without significant effects to the readings from the magnets, ferrous materials, and electrical currents present on the boat. Best positioning results are also obtained with track-over-ground close to 0, 90, 180 or 270 degrees. For boat-towed operations, it is best to have the GPS antenna centrally mounted at the stern of the boat or, if practical, to have the GPS antenna remotely-mounted on a towed float directly above the sensor.  For land survey operation, set distance behind boat to zero.

To set the distance-behind-boat value, click SETUP and Distance Behind Boat from the menu at the upper left of the MagSurvey screen. A popup form will appear with a display of the currently-set value. Change the value as necessary and then press OK, or ENTER (or press Cancel to exit without changing).

The GPS and Magnetometer should be connected to the computer’s two available serial ports. Click Setup and Equipment and Communications from the menu at the upper left of the MagSurvey Screen. A popup form will appear.

Setup of Communications Ports

On a new installation, set the com-port settings to match your computer's hardware, and set the baud rates to match those of your GPS and magnetometer.  Sensing all data on a combined channel is also possible -- if your magnetometer supports this configuration.  On some GPS receivers, choosing a higher baud rate might allow for more frequent position updates (one second vs. two seconds).  Refer to Equipment Requirements (above) and to your equipment manuals for information on baud rates.

Setup of Magnetometer Type

The form also has selections for magnetometer type, as well as areas for entering offset and scale factor information for magnetometers with depth and altitude sensors installed. The offset and scale factor values for the Geometrics magnetometers are determined by using the Geometrics software included with the magnetometer (this software may also be downloaded from the www.geometrics.com web site).

Setup of the Active Survey Scale

The form also has an area for the selection of the active survey scale.  Select the default 0.004 minutes of lat/lon (large-scale, recommended for marine surveys --1224 feet north-south), one of the two smaller scales, or one of the three larger scales.  The selected scale determines the maximum area for the survey, and further information is included on the setup screen.  For each mode you can only reload or save files of the same scale.  The two coarse modes  (coarse and extra coarse) are intended for rough searching only.

Zero Depth Readout

A button exists to zero the reading from the depth sensor of marine magnetometers so equipped.  The magnetometer should be on the deck of the boat or on the surface of the water for use of this feature.

Magnetometer Display Sensitivity Mode Setting

MagSurvey has two sensitivity settings that affect the 2D and 3D display plots, and the magnetometer graph.  The default is Normal sensitivity, but you may choose High sensitivity for surveys involving very weak anomalies.  The saved data is the same for both modes, and surveys can later be brought up for display in either mode.

Require Differential Corrections Check-Box

MagSurvey defaults to requiring differential GPS corrections in order to assure the best accuracy of plotted anomalies -- PSI strongly recommends operation in this mode.  However, if the user is comfortable plotting anomaly locations without WAAS, radio beacon, or other differential corrections being required, then this check-box may be unchecked by clicking with the mouse button.

Setup the Software License Key

MagSurvey was costly to develop, involving large amounts of research and software development time. To prevent pirated use of the software, MagSurvey takes certain information from the computer to compile an identifying number which is shown on the Setup screen as the Installation Code. MagSurvey is sold for use on a single computer and multi-computer licenses are available at an extra cost. Two modes of operation are possible:

1. Full Licensed Capability – To Enable the full capability of the program it is necessary that the user purchase a license and phone (561-433-0033) or E-Mail (info@magsurvey.com ) the SETUP screen’s Installation Code number to Perception Systems, Inc. in Florida, USA. For registration, customer name, address, and contact information will be required. At that time, a Software License Key number will be provided. Enter this number exactly into the space provided, select save (see below), and MagSurvey will be fully functional the next time the program is run. Record your numbers, and keep them for future reference.  The license key enables a single computer to run MagSurvey for land and marine surveys.

2. MagSurvey Demo – For evaluation purposes, most of the features of MagSurvey are enabled without entering a Software Key number.  This gives the potential purchaser an indication of how MagSurvey will work in his particular setting, with the equipment that he has on hand.  Save-Survey, Print-Screen, and screen redraws are disabled in this mode; and messages on the plot screen reduce the usable survey area. The MagSurvey demo software can be used as a fully functional tool to review previously recorded surveys, thereby allowing analysis on separate office computers at no additional cost.

Finally, make any additions or changes necessary, and either select Save New Setup Parameters to save, or select Cancel to exit without saving. These saved values are stored in a file called MagSurvey.Cfg, and will be loaded as defaults whenever MagSurvey is run.