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GSSI Profiler EMP-400 Manual

Electromagnetic induction tool
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Summary of Contents for GSSI Profiler EMP-400

  • Page 2 Copyright © 2008-2015 Geophysical Survey Systems, Inc. All rights reserved including the right of reproduction in whole or in part in any form Published by Geophysical Survey Systems, Inc. 40 Simon Street Nashua, New Hampshire 03060-3075 USA Printed in the United States SIR, RADAN and UtilityScan are registered trademarks of Geophysical Survey Systems, Inc.
  • Page 3 OF ITS EQUIPMENT, WHETHER OR NOT DEFECTIVE. Before returning any equipment to GSSI, a Return Material Authorization (RMA) number must be obtained. Please call the GSSI Customer Service Manager who will assign an RMA number. Be sure to have the serial number of the unit available This device complies with Part 15 of the FCC Rules.
  • Page 7 If you find that an item is missing or damaged during shipment, please call or fax your sales representative immediately so that GSSI can take steps to correct the problem. Your EMP-400 system (Standard Configuration) includes the following items: 1 –...
  • Page 8 Electromagnetic induction instruments are used for many different types of geologic, engineering and environmental investigations. These include shallow soils mapping, soil-salinity mapping, ground water investigations, the detection and delineation of waste pits and associated subsurface contaminants from acids, salts or volatile organic contaminants (VOC’s). They have also been used extensively for the detection of conductive geologic media such as clays and ferrous mineral deposits, as well as the detection of resistive geologic materials such as sand and gravel deposits.
  • Page 9 The Profiler has no external connectors or I/O ports. An expanded view of the Profiler electronics enclosure is illustrated in Figures 3 and 4. The Profiler is powered by re-chargeable Li-Ion batteries. The batteries are accessible via the removable battery pack located on the bottom of the electronics assembly.
  • Page 10 Retaining Clip Locks The battery pack is removed from the unit by gently pulling the removable battery pack retaining springs towards each other i.e., towards the center of the battery pack, until they snap out from beneath the four (4) retaining clips screwed into the bottom of the electronics. The locks on the battery pack retaining clips prevent the clips from accidentally opening when the electronics enclosure base brushes against tall grass, field stubble, or other near-surface objects.
  • Page 12 The Li Ion battery is inserted into the Profiler battery pack by inserting the battery and gently pinching the battery pack housing springs back until the battery snaps into place. The battery pack is then inverted and then inserted into the electronics enclosure. The User should gently squeeze the battery pack retaining clips and then insert the battery pack into the Profiler electronics assembly using the insertion guideposts.
  • Page 13 The Tripod Data Systems (TDS) Recon-400 is a portable, field rugged PDA. It is the platform for the Graphic User Interface and data storage of the Profiler. GSSI assumes no responsibility for Profiler interface operating difficulties if the User installs any additional third-party software in the Profiler PDA or reconfigures the PDA Bluetooth connection for operation with any other devices.
  • Page 14 The TDS Recon-400 has three (3) primary connectors: One (1) AC battery charger connector, One (1) D-Shell RS-232 serial port connector and one (1) USB data port.
  • Page 15 The User should place the PDA on charger upon unpacking the instrument. The Windows operating system is stored in non-volatile memory. GSSI recommends placing the PDA on the charger for several hours after every survey or when the PDA battery gas gauge reads 25% or less.
  • Page 16 The AA power boot module accepts two (2) AA batteries. Under normal operating conditions and with the appropriate batteries, the AA power boot module will operate for approximately 2-3 hours. When using the WAAS GPS, the PDA operating time drops to .5 hours.
  • Page 17 Do not force the ball joint armature without unlocking the ball joint. This will damage the ball joint. GSSI does not recommend using PDA mount when the low carry handle is used. The PDA display will not be visible to the User.
  • Page 18 The Profiler handle allows the User to carry the instrument in closer proximity to the ground surface. The Profiler In-Phase response will improve the closer it is to the ground surface. The low carry handle is attached to the tube with the two screw-clamps provided with the handle. The low carry handle, clamps and clamp screws are illustrated Figure 13.
  • Page 19 (20 to 25 cm) from the ground surface. To obtain reasonable apparent conductivity ( ) values GSSI recommends that the Profiler be deployed with the low carry handle and operated at a transmit frequency of 15 kHz. This is discussed in...
  • Page 20 The EMP-400 is supplied with a remote RF key fob for remote Start/Stop of Profiler during data acquisition and for placing fiducial marks in data files collected in the Continuous mode.
  • Page 21 GSSI strongly urges the User to review the system setup procedures in Chapter 2 carefully and use them as a step-by-step guide when configuring the system. Prior to starting system setup and data acquisition, insert a fully charged Profiler Li-ION battery into the removable battery pack (see Section 1.4: Profiler Removable Battery Pack).
  • Page 22 After starting the Profiler software program, the RECON-400 will display the PROFILER splash screen. Beneath the splash screen a Blue progress bar will appear. When initialization is complete, the progress bar and splash screen will disappear and the Main menu will be displayed.
  • Page 23 When communication is established between the Profiler and the PDA, the PDA will display the Main menu. At the bottom of the screen, the PDA battery charge status, the speaker status (On/Off) and the current system time are displayed. If the User has stored a previously saved setup it can be recalled by selecting Recall Setup and then selecting the desired setup number.
  • Page 24 To recall a setup the User should select Recall Setup from the Main menu and select the desired setup number. The system will prompt the User with a courtesy check above. The User should select YES. The GPS setup and the system calibration parameters are NOT saved in a Saved setup. If the User is using a GPS, a GPS test must be conducted with the Internal or External GPS to assess the GPS signal condition and GPS validity.
  • Page 25 Prior to starting the survey, the User may record project information for permanent record. Site data often includes a Project name which may consist of a site location or job number. In addition, the identity of the operator, the date and time when the data was collected and the units (English or Metric) are all useful information to archive.
  • Page 26 The User can enter information on the job site or location. This field can contain a maximum of 21 characters. The User can enter information on the system operator. This field can contain a maximum of 21 characters. This field contains the File Name and Number of the next data file to be collected. The default data file names are written in the form EMP400___001.EMI.
  • Page 27 To access the Project Parameters, the User should select Project Parameters. The Project Parameters screen displays all of the User selectable data acquisition parameters and Grid Configuration parameters. The Project Parameters menu can be accessed directly from this menu by selecting any of the Parameter fields;...
  • Page 28 User. This function can only be accessed with a GSSI supplied installation update file. Slection of this field opens the Systems Calibrations menu where the User must perform several required...

  • Page 29: Screen Colors

    The User should select Display Preferences to set the display paramters for the PDA.  Screen Colors (page 23)  Data Display Colors (page 24)  Data Display Limits Setup (page 25)  Positioning Dsiplay (page 25)  Map Smoothing (page 27) ...

  • Page 30: Data Display Colors

    Text (active menu selections under the function Button) and Focus Backgr (the background behind the Focus Text) allow the user to further customize the function Buttons as desired.  GSSI recommends that the User experiment with these functions. Once the desired colors have been chosen, select Save. ...

  • Page 31: Data Display Limits Setup

    When the User is satisfied with the color(s) select Save Colors > OK from the PDA Status Bar to return to the Display Preferences menu. GSSI recommends that the User avoid selecting light grey or gray as data display colors for the line graph display. These colors will be difficult to see against the white data display background.
  • Page 32 Quadrature data are not clipped off the top or bottom of the display. If, during the course of collecting the test transect, the User notes that the data has exceed the scale the display, GSSI recommends that the lower and upper limits on the Graphic display be reset or the scale of the Graphic display set to a Logarithmic scale.

  • Page 33: Map Smoothing

    The Map Smoothing function acts to smooth the level contours on the contour map display in the Review Data section of the Main menu. To enable this function, tap in the box next to MAP SMOOTHING. The Data Smoothing filter is a 5-point center-weighted triangular filter applied to the data during data collection.
  • Page 34 The User should navigate to the System Setup menu. This menu contains all of the User selectable parameters required for system data storage, system beeper, internal or external GPS function settings and GPS test. To access this menu, select System Setup. ...
  • Page 35  If the number of satellites equal to or greater than four, the GPS solution is valid. This is the GSSI recommended setting for both the internal WAAS and external GPS validity.  If the number of satellites is equal to or greater then 3, the GPS solution is valid.
  • Page 36 For Users who have the Profiler software installed in a Trimble GeoXT or GeoXH hand held GPS system, the displayed COMM port assignments are different than the standard GSSI Recon PDA. The Bluetooth COMM port may be either COMM 4, COMM 5 or COMM 6 depending upon the firmware installed in the Trimble PDA.
  • Page 37 1 (stop bit).  BAUD: 4800/9600.  The message rate must be set to 1 Hz.  The message type must be set to GGA. The Bluetooth communications port is preset at GSSI and cannot be modified by the user.
  • Page 38 The Select Parameters menu contains all of the data acquisition parameters. To access this menu > Select Parameters.  Mode (page 32)  Interval (page 33)  Freq 1 (page 33)  Freq 2 (page 33)  Freq 3 (page 33) ...

  • Page 39: Interval

    In stationary mode, data collection is initiated by selecting Start Data Collection, then depressing the Enter () key on the PDA keypad, or by depressing the Start button on the RF key fob. The system will beep and the Blue communication status lights will blink when the data has been recorded and a data point will appear on the PDA data display in the data display format selected by the user.

  • Page 40: Orientation

    After selecting the desired transmit frequencies tap OK on the PDA screen or press OK on the PDA keypad to return to the Select Parameters screen.  If the User selects more than one (1) transmit frequency for data collection, the user must select the frequencies in numerical order, i.e., FREQ 1 then FREQ 2 and then FREQ 3.
  • Page 41  On the left of the screen is the Vertical Dipole Mode. The two instrument orientations are VDM broadside (top left) and VDM inline (bottom left).  On the right of the screen is the Horizontal Dipole Mode. The instrument orientations are HDM broadside (top right) and HDM inline (bottom right).

  • Page 42: Stacking

    The Stacking function will operate in both the Continuous and Stationary modes. Stacking is the number of successive readings averaged at each data collection point. Stacking is used to suppress random noise and improve the signal-to-noise ratio of the data. Stacking is useful in areas where random noise, cultural noise or intermittent noise ‘spikes’...
  • Page 43 Prior to data collection, the User must calibrate the Profiler for the local site conditions. This calibration compensates for the presence of the operator and the PDA as well as the operating height and local ambient noise conditions. In addition, the system must compensate for the presence of an external GPS system if one is used during data collection.
  • Page 44 After the User enters the operation height, the system will issue a warning that the In Phase values may be innacurate when operated between 12 and 20 inches (30.5 and 50.8 Centimeters). Due to this calibration issue, the Magnetic Susceptibility output for the current version of the software has been disabled.
  • Page 45 The Profiler will begin to calibrate for the selected Transmit frequencies. When the Field Calibration is complete, the system will prompt the User to pick up the instrument. Prior to conducting the Operator Calibration, the User should remove all large metallic objects from their person.
  • Page 46 The User should never perform a Free Space Claibration. This calibration has been performed at GSSI. If the User selects the Free Space Cailbration the system will issue the following warning. If this warning should appear, the User should select No.
  • Page 47 GSSI recommends that these files be copied from the Profiler Accessory CD and stored in a safe location on a PC as additional backup in the event the Accessory CD and the calibration files on it are lost or become corrupted or damaged.
  • Page 48 The User should navigate to the Select Parameters menu and select Use Zero Level for In-Phase. The User should perform the In Phase zero in an area where they are confident they are not in proximity to buried metal or near-surface metallic objects. The User should be holding the instrument at the height at which data will be collected with either the shoulder strap or low carry handle.
  • Page 49 The values for the selected frequencies will begin to rise or fall depending upon the frequency selected. The Set In-Phase Zero display field will now change to Stop Profiler. The User should wait approximately 10-20 seconds for the values to stabilize, i.e., the rate of change in In-Phase values will decrease.
  • Page 50 The User should then select OK to return to the Select Parameters menu and check the Use Zero Level box. A black X will appear in the box indicating that the displayed In-Phase component will have the Set Zero level values added (or subtracted) from the acquired In-Phase values. To reset the In Phase Zero levels select Reset.
  • Page 51 The User must select the survey units in the Project Parameters menu prior to setting the Grid Parameters. If the User sets the Units to METRIC, then sets the Grid Parameters, and then resets the Units to ENGLISH, the Grid Parameter units will contain conversion rounding errors. At this point the user would have to re-enter the correct Grid Parameter values prior to collecting data.
  • Page 52 Step (station) number will increment at the value selected. GSSI recommends that only whole number values (1, 2, 3, etc.) or even fractional values be used for the Step value. If the step value is number such that when divided into the transect maximum it yields a floating point repeating decimal, the transect value will be rounded down.
  • Page 53 The Profiler will store a maximum of 500,000 grid point readings. The small, black square box on the Grid Type icon indicates the starting point (origin location) of your survey. The system will toggle between X Traverse and Y Traverse. The traverse direction indicates the orientation of the survey along the X or Y-axis.
  • Page 54 This menu displays all the possible Y-axis survey transect directions available to the User. The label convention is as follows:  Y-axis profiling, starting at the left bottom (LB) corner of the survey grid (unidirectional).  Y-axis profiling starting in the left bottom (LB) corner of the survey grid with lines collected in a zigzag (Z) fashion.
  • Page 55 The User must select a Setup Number location. There are thirty (30) memory locations available to the user to save survey setup parameters. To select a Survey memory location, simply tap on the Survey number and then tap OK on the PDA Status Bar to return to the Main menu. Once the User has configured the Profiler for data collection, the User should navigate to the Collect Data menu.
  • Page 56 To start data collection the User must select the Enter key () on the PDA keypad. The PDA will begin to display the data in the display graph and as numeric values next to each of the transmit frequencies selected. The Line Number (L.0.00) and the Station number (S0.00) will be displayed at the top of the screen.
  • Page 57 If the Profiler has been configured to collect data on a survey grid without GPS, the data display screen can be changed to the TRAJECTORY screen by tapping the PDA screen during data collection. This screen will display the Line number (L0.0) and the station\reading number (S29.00) and grid type (XTr).
  • Page 58 To advance to a new line the User should select Advance To New Line. The line number will increment (or decrement). The User should then select Continue Data Collection to restart data collection on the new line.  If the User taps the data collection screen, the Trajectory will now display the updated position on the grid.
  • Page 59 Increments or decrements the line number based upon the value for Spacing entered in the Grid Config. menu. Deletes the current line. This function can be used to delete all lines in the current grid. Skips or increments the station number based on the value entered in Step in the Grid Config.
  • Page 60 Grid Config menu to set the X and Y axis extents in order that the PDA display ‘covers’ the entire survey area. GSSI recommends setting the X and Y grid maximums as close to the size of the survey area as possible.
  • Page 61 The User must confirm that the GPS solution is Valid by conducting sa GPS TEST. Once the User has established the GPS solution is valid the User should navigate to the Collect Data menu and select the GPS DISPLAY type Levels.
  • Page 62 The User must then navigate to the Select Parameters menu and select the ‘Freeway’ data collection mode. In the Freeway mode the data mapped to the Levels color map display is positioned based upon GPS information only. The system does not use any of the Grid Config. parameters to draw the data to the screen.
  • Page 63 The Data Display Colors menu allows the User to set the data display color for data displayed in line graph or bar graph mode. The section of the Data Display Colors menu that controls the Levels display functions is outline in in the figure below.
  • Page 64 The coarse ‘broken’ rainbow display which contains 32 color bins and an assymetric color distribution. When using the Levels function the User may only display one component type i.e. In-Phase, Quadrature or Conductivity. The “Dot Size’ parameter allows the User to adjust the size of the color map node on the data collection color map display.
  • Page 65 The User may change the color dot size by selecting the left << or right >> arrows with the PDA stylus, The Color Dot size will increment and decrement in steps of .2 (in feet or meters).
  • Page 66 Once the User has selected the desired map range and dot size parameters, navigate to Collect Data menu. Start data collection by selecting Start Data Collection and then tap the PDA display or press the Enter key on the PDA keypad. The system will display the collect data display screen, however the system will not start until the User presses the Enter key again.
  • Page 67 Once the system has established a heading it will reposition the data along the X (bottom) axis. The data will always be positioned along the x axis regardless of the grid type (X or Y) selected by the User. The GPS quality will be indicated by a green GPS symbol in the upper left of the display.
  • Page 68 In the figure below we have selected a 50 X 50 ft grid and are collecting data at a speed of 2 Hz i.e., 2 readings per second. The transects are ‘spaced’ approximately 2 feet apart. Inspection of the figure reveals that we have a slight ‘gap’...
  • Page 69 If desired, the User can increase the dot size further to cover the gaps between the transects or adjust their pace and heading to suit the chosen display scale. The User also has the option of ‘zooming’ or ‘shifting’ the display by pressing the left, right and up or down arrow keys on the PDA keypad.
  • Page 70 When the User has completed the survey they may select “SAVE IMG” on the vertical axis of the color map display to save a bitmap image of the color map display.
  • Page 71 The Review Data menu allows the User to review, delete or quick contour data which was collected with User grid parameters. Select Main > Review Data.  Project (page 65)  File (page 66)  REVIEW LAST FILE (page 66) ...
  • Page 72 Select the Project in which the file to be reviewed resides. Common.prj is the default Profiler project directory. Once the desired Project has been selected, the project name will appear in the Project field. The User may then select the desired file(s). Tap File and select the desired file name to Review the file. Once a file has been selected the Select Data Value screen will be displayed.
  • Page 73 From this screen, the User may select the frequency and the specific component of that frequency to be displayed as a contour map. The Profiler contouring algorithm is very simple and uses a triangular nearest-neighbor method to grid and contour the data. This function serves as a quick way to review your acquired data in the field.
  • Page 74 There are five (5) system defined Color Tables. These are displayed horizontally on Color Map Tables menu as five separate color bands:  2 - 16-shade color tables (top)  1 - 256-shade color table (blue, white, red-middle)  1 – 16-shade grayscale (second from bottom) ...
  • Page 75  To delete a file, groups of files or an entire directory of files, select Review Data > Delete Files. The Delete File menu display will appear.  To delete a single file, select the box next to the file to be deleted, and then tap Delete. ...
  • Page 76 In the event that the Bluetooth communications between the PDA and the Profiler is lost during data collection, the User may recover the data by using the Recover Last File function To shut down the data collection interface after completion of the survey, return to the Main menu, and tap OK on the PDA status bar.
  • Page 77 The TDS RECON-400 PDA utilizes a USB connection and Windows Mobile (Microsoft ActiveSync) to transfer data from the PDA. The User must have Windows Mobile or ActiveSync version 4.1.0 (or higher) installed on their computer and/or the Profiler File Transfer Utility program. If the User does not have ActiveSync installed on their PC it can be downloaded from the Microsoft support site at the following URL: The User should also have installed the MagMap2000 software which was supplied with the system.
  • Page 78 Data can be transferred directly from the PDA to the computer with Windows Mobile Device Center or Activesync, or the User may use Profiler File Transfer Program/File Transfer Utility interface. The File Transfer Utility interface is designed to access the Profiler storage memory. It is necessary to install Windows Mobile\ActiveSync in order for the File Transfer Utility to function correctly.
  • Page 79 If the PC has Windows Mobile installed, the User should select Connect without Setting up your Device. The User should then select File Management. The User should select Browse the contents of your device.
  • Page 80 The system will now display the Recon PDA as a drive. The User should then browse the PDA to the system root and open the PROFILER folder..
  • Page 81 Inside the Profiler folder the User will find the DATA folder.. The User should open the DATA folder and then open the desired project folder. COMMON is the default Profiler project folder. The User should open the desired project folder and COPY or MOVE the Profiler files to the desired location on their PC.
  • Page 82 (CSV) file. It is suggested that EXCEL be used only to review the .EMI data file. If it is necessary to edit the file, GSSI recommends that the file first be converted to an *.dat file in the MagMap program.
  • Page 83 ActiveSync will then connect the PDA and PC and the ActiveSync connection window will appear. To access the PDA system and memory, select the Explore icon. This will access the Mobile Device window.
  • Page 84 Some files in the PDA root directory are required system files or log files. These files should not be opened, moved or deleted from the PDA root directory. GSSI assumes no responsibility for the proper operation of the EMP-400 if any of these files have been accessed, moved or deleted.
  • Page 85 The user will note there are three (3) files types: This is file of the survey grid collected. This files is used to create the Review Data contour map. This file can also be displayed in the 3D Mode in the GSSI GPR data processing program, RADAN™.
  • Page 86 A GPS file is stored by the system if the WAAS GPS is enabled or the user has connected an external GPS unit to the PDA (see Section 2.2: Check System Diagnostic Parameters). Figure 116 is an example of a multi frequency file collected with a GPS system. All of the data acquisition and grid parameter information is written in the header above the data.
  • Page 87 Figure 117 illustrates the standard Profiler GPS file. The format of all Profiler GPS files is standard NMEA GGA format. This file is compatible with the MagMap2000 GPS Conversion and Processing functions. It can also be converted to other co-ordinate types by the User in MagMap2000 and with the appropriate formulas in Microsoft Excel™.
  • Page 88 The EMP400__#.dzb file type is a two dimensional binary bitmap. It is used to generate the contour map display in the Review Data menu of the PDA. Prior to transferring data to the PC, the User should create a destination folder for the data. Once the folder has been created on the PC, the user simply has to use the Windows copy, paste, or move functions to copy or move data from the PDA to the destination folder on the PC.
  • Page 89 Data can also be transferred from the PDA to PC by using the Profiler Transfer Utility. As indicated, the File Transfer Utility requires that ActiveSync be installed on the PC and the PDA The File Transfer Utility can be copied directly from the Accessories CD provided with your EMP-400 to your PC desktop.
  • Page 90 Upon first opening the program, the User may have to select the Files of Type box located at the bottom of the File Open dialog box, and select the GSSI Profiler (*.EMI) file type. The system will now recognize the *.EMI files.
  • Page 91 Profiler*.EMI files. To open a file, select the file with the cursor and click Open, or simply double- click on the desired file. Upon opening the file, the MagMap2000 program will open the GSSI Profiler Information display. This is information comprises data stored in the file header.
  • Page 92 As discussed in Chapter 2 Fiducial Marks, it is important that the User has entered the correct value for the Marker Spacing in the Grid Config menu. In the following example the data file is an xLBZ grid with X and Y origin at zero. The origin is in the lower left hand corner of the grid. The grid has an X and Y maximum of 50.
  • Page 93 The file can currently be exported in SURFER, GEOSOFT, TEXT (Space Delimited) and SURFER 3 column (X, Y, Z) data file formats. The converted file will be created and can be written back into the directory of choice by using the Select Output Path/File Name tab. After designating a file name and the target directory for the export file, select Export Now.
  • Page 94 GSSI Profiler (*.EMI) file type before the system will recognize *.EMI files. Once the User has selected a file to process, the MagMap2000 program will open the GSSI Profiler Information display. This is information comprises data stored in the file header.
  • Page 95 After selecting Use GPS positions to load the data, MagMap 2000 will display the data in Decimal Degrees format. The green squares indicate the start coordinate of a survey line, and the red squares indicate the end coordinate of a survey line. The blue squares indicate reading locations and the black arrows superimposed on the blue squares indicate the direction in which the transects were acquired.
  • Page 96 There are several functions available for smoothing/transforming the EM/GPS data in MagMap2000. The first function is the UTM transformation (Universal Transverse Mercator). This function will transform the GPS decimal degrees geographical coordinates to UTM coordinates. Select GPS for the MagMap2000 toolbar, and then select UTM Setup. To convert to UTM coordinates, select the Enable UTM transformation box.
  • Page 97  This is the type of ellipsoid used to approximate the shape of the earth. Since the Earth is not a perfect sphere, some ellipsoids may be closer approximations to the region where the survey was conducted than others. The current standard ellipsoid is the WGS-84 (World Geodetic System, 1984 ellipsoid).
  • Page 98 Zone C.M. Range Zone Range 177W 180W-174W 003E 00E-006E 171W 174W-168W 009E 006E-012E 165W 168W-162W 015E 0012E-018E 159W 162W-156W 021E 018E-024E 153W 156W-150W 027E 024E-030E 147W 150W-144W 033E 030E-036E 141W 144W-138W 039E 036E-042E 135W 138W-132W 045E 042E-048E 129W 132W-126W 051E 048E-054E 123W 126W-120W...
  • Page 99 These are constant values that you (usually) add to your UTM coordinates. UTM Coordinates are usually large numbers of approximately a million meters; however, your survey may be on the order of tens, hundreds or thousands of meters. This allows you to simplify your final numbers by adding or subtracting the large offset values.
  • Page 100 After selecting the GPS menu option > Smooth positions, select the GPS Smooth Position option from the Main menu and the Line Smoothing Parameters Setup window will be displayed. This dialog box lists all of the lines in the survey (in this example 19). The User will also see a series of parameters that can be set to manipulate the magnitude and type of smoothing.
  • Page 101 This is the number of the line to be smoothed. Turns the smoothing on or off for any given line. This controls the degree of smoothing applied to the selected line. The higher the value, the greater the degree of smoothing. This allows the User to select whether you would like to despike before smoothing.
  • Page 102 An inspection of Figure 134 shows that some lines are straighter than others. In this example, some transects required the operator to walk around obstacles during data collection. However, all lines have had the same degree of smoothing applied. The User could smooth out Line 0 and 1 (top of the map) and Lines 8 and 9 (middle of the map) by applying another pass of smoothing with a higher smoothing parameter.
  • Page 103 WAAS GPS is a navigation system designed to provide instantaneous position, velocity and time information almost anywhere on the globe at any time, and in any weather. It typically provides positioning accuracies of approximately 3 meters. Since GPS receivers need to see much of the sky, it works poorly indoors, in the woods and in urban and semi-urban areas where nearby buildings create GPS signal multi-path problems.
  • Page 104 Satellite Satellite Ionospheric Ionospheric Refraction Refraction Tropospheric Tropospheric Refraction Refraction MultiPath MultiPath Reflection Reflection The Wide Area Augmentation System (WAAS) is a form of differential GPS that uses geostationary GPS satellites to transmit an error correction estimate back down to your GPS receiver. The measured positions of ground reference stations, strategically positioned across the country, are transmitted up to the WAAS satellites.
  • Page 105 GPS information. The EMP-400 uses the NMEA 0183 version 2.1 protocols. The Profiler EMP-400 WAAS GPS receiver has been configured to send a GGA message string and the PDA will accept only a GGA message string. No other NMEA strings are supported for the Profiler by GSSI.
  • Page 107 STRING: $GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh GGA = Global Positioning System Fix Data 1 = UTC of Position 2 = Latitude 3 = N or S 4 = Longitude 5 = E or W 6 = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix) 7 = Number of satellites in use [not those in view] 8 = Horizontal dilution of position 9 = Antenna altitude above/below mean sea level (geoid)
  • Page 109 Prior to conducting any survey, the user should evaluate the objective(s) of the investigation and the survey site conditions. The survey objective should be carefully considered, as this will determine the frequency(ies) of operation, the mode(s) of instrument operation and the spatial sampling density required.
  • Page 110 primary survey objective, this information is of primary importance in any planning decisions regarding survey grid location, orientation, and transect spacing. The topographic variations at the site should also be evaluated during the survey planning stages. Significant topographic variation in some geologic settings can have an effect on subsurface induction readings.
  • Page 111 and highly recommended practice to create a map of the survey grid with specific grid locations referenced to permanent or semi-permanent surface features. The investigator should update this map, along with the survey notes if any of the data acquisition or survey grid parameters are changed during the survey.
  • Page 112 Figure 139 is an illustration of an example site plan map. This is an example of the line-and-station system used by most investigators in the field. An origin (relative, benchmarked or geo-referenced) is defined for the local co-ordinate system. The distance along the baseline from the survey origin to an orthogonal survey line is (generally) given as the survey line number i.e.
  • Page 113 The use of GPS systems to collect geo-referenced data along with geophysical data has become much more prevalent in recent years and the EMP-400 is equipped with a WAAS (Wide Area Augmentation System) GPS and is compatible with external, high-resolution GPS systems. In many survey locations, the absence of sufficient satellite coverage and the multi-path interference caused by nearby buildings or other structures may render the use of GPS positioning systems impractical or problematic at best.
  • Page 114 and receiver on two parallel traverse lines and the line between the transmitter and receiver aligned perpendicular to the transect direction. Each method has its advantages and disadvantages. Under certain field conditions, collecting data with the in-line method affords the operator somewhat greater control over unwanted movement of the coils during data collection.
  • Page 115 Connect the PDA to the PC with the USB cable provided with the system. Locate the folder where the backup Calibration Files are stored. This folder will include a PROFILER.CAL file and a PROFILER.PRM file. Wait for ActiveSync (or Windows Mobile) to prompt you with the Pocket PC Sync Setup Wizard. Select Cancel as you do not want to establish a sync relationship between the PDA and your computer.
  • Page 116 The User should now select the Program Files folder. This will allow access to the Profiler Program folder. The user should now select the Profiler folder. This folder contains the following PROFILER.PRM, PROFILER#.CAL (# indicates serial number of the Profiler EMP-400). The files PROFILER.PRM, and PROFILER#.CAL are the system calibration files.
  • Page 117 The user should NEVER move the Profiler executable PROFILER.EXE or the PROF_MEM_56K file. Doing so will prevent the system from operating. GSSI assumes no liability for the proper operation of the EMP-400 if these files are moved or deleted. The User should Copy the backup PROFILER#.CAL and PROFILER.PRM from their PC to the Profiler Program Files folder.
  • Page 119 Carmichael, R. S., (ed), 1989, Practical Handbook of Physical Properties of Rocks and Minerals., 2 CRC Press, Inc., Boca Raton, FL. Frischknecht, F.C., 1967, Field about an oscillating magnetic dipole over a two-layer earth and application to ground and airborne electromagnetic surveys, Quart. Colorado School of Mines,Vol. 62, No.
  • Page 120 Waite, J.R., 1962, A note on the electromagnetic response of a stratified earth: Geophysics, 27, pp. 382- 385. Waite, J.R., 1982, Geo-Electromagnetism. Academic Press, Inc., N.Y. Ward, S.H., and Hohmann, G.W., 1987, Electromagnetic theory for geophysical applications. in Nabighian, M.N., Ed., Electromagnetic methods in applied geophysics, Vol. 1. pp. 131-311. Society of Exploration Geophysicists.