pulseEKKO PRO USER ’S GUIDE Copyright 2005 Sensors & Software Inc.
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pulseEKKO PRO Table of Contents Table of Contents 1 Overview ............................................................................................................1 2 System Assembly and Startup .............................................................2 2.1 2.2 2.3 System Configurations .................................................................................2 2.1.1 Low Frequency Hand Held ..............................................................2 2.1.
Table of Contents 3 pulseEKKO PRO 2.6.1 Powering the DVL and Control Module .........................................25 2.6.2 Powering the Low Frequency Transmitter and Receiver ..............26 2.6.3 Digital Video Logger ......................................................................26 2.6.4 Main Menu .....................................................................................27 2.6.5 Using the Software Menus ............................................................
pulseEKKO PRO Table of Contents 3.3.5.2 Set Odometer Manually ........................................................49 3.3.5.3 Odometer Direction...............................................................49 3.3.6 3.4 3.5 Fibre Optic Testing.........................................................................49 Survey Parameters ....................................................................................50 3.4.1 Start Position ..........................................................
Table of Contents 5.4.2 5.5 pulseEKKO PRO Fiducial Markers for GPS...............................................................73 Data Collection Pause Menu .....................................................................73 5.5.1 Exit .................................................................................................73 5.5.2 Continue .........................................................................................73 5.5.3 Scale ..........................................
pulseEKKO PRO Table of Contents 6.12.1 Borehole GPR ................................................................................93 6.12.2 Walls, Pillars and Monument Surveys ...........................................94 7 Troubleshooting ..........................................................................................95 7.1 8 9 Power Supply .............................................................................................96 7.1.1 DVL and Control Module Power Requirements ....
Table of Contents 10 pulseEKKO PRO Helpful Hints ................................................................................................117 10.1 Batteries ...................................................................................................117 10.2 Measuring Position ..................................................................................117 10.3 Data Files .................................................................................................117 10.
pulseEKKO PRO 1 1-Overview Overview This manual describes how to set up and run a pulseEKKO PRO LF (low frequency) Ground Penetrating Radar (GPR) system connected to a Digital Video Logger (DVL) for data display and storage. System Assembly & Startup: Section 2 System Assembly and Startup on page 2 details the step by step procedure for assembling the pulseEKKO PRO system. It also describes how to start up the DVL and navigate around the menus.
2-System Assembly and Startup 2 2.1 pulseEKKO PRO System Assembly and Startup System Configurations The modular design of the pulseEKKO PRO GPR makes the system very flexible and readily field-portable in a number of configurations. This section details the steps for assembling the Low Frequency Hand Held (Figure 2-1) and High Frequency Hand Towed (Figure 2-2) configurations. 2.1.
pulseEKKO PRO 2-System Assembly and Startup 2.1.2 High Frequency Hand Towed There are four essential components to the high frequency radar system: the Digital Video Logger (DVL), the control module, the transmitting transducer and the receiving transducer. The control module is attached to the back of the DVL. The transducers are connected to the control module via the transducer cables (Figure 2-2). Figure 2-2: The complete high frequency pulseEKKO PRO tow mode assembly.
2-System Assembly and Startup 2.2 pulseEKKO PRO DVL and Control Module The DVL and Control Module are common to all configurations. 2.2.1 Attaching the Control Module to the DVL The control module unit must be attached to the back of the DVL (Figure 2-3). This may already have been done at the factory. Proceed to the next section, if this is the case. Figure 2-3: The DVL with the control module attached to the back.
pulseEKKO PRO 2-System Assembly and Startup Figure 2-5: Attach the control module to the DVL using the 4 screws supplied (left) and a Phillips screwdriver (not supplied). Tighten the 37 pin connectors into place (right) with a small slotted screwdriver (not supplied). 2.2.2 Attaching the Fibre Optic Converters for Low frequency Antennas Low frequency, unshielded antennas in the frequency range from 12.5 to 200 MHz require fibre optic cables to connect the transmitter and receiver to the control module.
2-System Assembly and Startup 2.3 pulseEKKO PRO Low Frequency Transmitter, Receiver and Antenna Assembly 2.3.1 Low Frequency Antennas The pulseEKKO PRO can be used with many different antennas. There are 5 low frequency, unshielded, bistatic antennas available: 12.5, 25, 50, 100 and 200 MHz (Figure 2-7). The best frequency of antenna to use on a survey depends on the survey objectives (Section 3.2.1: P34). Figure 2-7: Low frequency, unshielded, bistatic antennas available for the pulseEKKO PRO.
pulseEKKO PRO 2-System Assembly and Startup 2.3.2 Attaching the Sockets to the Transmitter and Receiver Insert and tighten the two female brass antenna sockets into the bottom of the transmitter and receiver electronic boxes (Figure 2-8). Tighten the sockets finger-tight. DO NOT APPLY UNDUE FORCE! Figure 2-8: Hand tighten the brass sockets into the bottom of the transmitter and receiver. 2.3.
2-System Assembly and Startup pulseEKKO PRO 2.3.4 Attaching the Mounting Blocks to the Antennas Attach the antenna mounting blocks to the antennas by using the flathead screwdriver to tighten the 4 (four) quarter-turn fasteners, ensuring that the male brass antenna pins protrude up the center holes of the mounting blocks (Figure 2-10). Quarter-turn fasteners work by aligning the screw in the socket and then pressing downward and tightening a quarter of a turn. DO NOT APPLY UNDUE FORCE.
pulseEKKO PRO 2-System Assembly and Startup 2.3.5 Latching the Transmitter and Receiver to the Mounting Blocks Carefully place the transmitter and receiver electronic boxes down onto the mounting blocks such that both brass pins fully connect (Figure 2-11 Left). Then use the 2 plastic draw latch connectors to hold the electronics boxes onto the mounting block (Figure 2-11 Right). Figure 2-11: Attaching the Transmitter and Receiver to the antennas.
2-System Assembly and Startup pulseEKKO PRO 2.3.6 Inserting Batteries into the Transmitter and Receiver With the transmitter and receiver power switched OFF, unlatch the 2 battery covers on the sides of the electronics and open (Figure 2-12). Place one 12-volt battery on each side on the electronics boxes making sure the positive (+) terminal faces inward toward the electronics (Figure 2-13). The battery is “keyed” with a notch in one side so it only fits properly in this orientation.
pulseEKKO PRO 2-System Assembly and Startup 2.3.7 Attaching Handles 2.3.7.1 Attaching the Adjustable Handles Attach the adjustable handle to the antenna using the flat head screwdriver to tighten the 4 quarter-turn fasteners as with the mounting block (Figure 2-14). This handle can then be adjusted for height by loosening the 2 levers by hand, moving the handle to the desired height and retightening the levers (Figure 2-15).
2-System Assembly and Startup pulseEKKO PRO 2.3.8 Connecting the Fibre Optic Cables The next step is to connect the transmitter and receiver to the control module. a) The pulseEKKO PRO low frequency system uses 2 dual fibre optic cables like the one shown in Figure 2-16. These cables should be tested periodically (Section 7.2: P99) and inspected for kinks or signs of damage and repaired if necessary (Section 9.6: P113). Figure 2-16: Dual fibre optic cable used with the transmitter and receiver.
pulseEKKO PRO 2-System Assembly and Startup d) After attaching the dual fibre optic cables to the transmitter and receiver, the other end of the fibre optic cables are attached to the fibre optic converters on the control module (Figure 218). The fibre optic cable from the transmitter connects to the fibre optic converter labelled 4. The fibre optic cable from the receiver connects to the fibre optic converter labelled 5.
2-System Assembly and Startup 2.4 pulseEKKO PRO High Frequency Transducer Assembly 2.4.1 High Frequency Transducers The pulseEKKO PRO can be used with many different antennas. Low frequency antennas in the range from 12.5 to 200 MHz were shown earlier (see Figure 2-7). There are also 3 high frequency, shielded, bistatic antennas available: 250, 500 and 1000 MHz (Figure 219). Each antenna box is really a “transducer” because it consists of both an antenna and the electronics.
pulseEKKO PRO 2-System Assembly and Startup 2.4.2 Mounting Transducers to the Skid Plate Skid plates are sized to fit a pair of transducers positioned side by side. Figure 2-20: Mounting the transducers onto the skid plate. The skid plate assembly consists of the bottom piece and two side flanges (top). The transducers are placed onto the bottom skid plate with the labels facing the same direction (middle) with the receiving transducer (R500) in front of the transmitting transducer (T500).
2-System Assembly and Startup pulseEKKO PRO 2.4.3 High Frequency Hand-Towed System One method of deploying the high frequency antennas is the Hand-towed configuration that includes the adjustable tow handle and an odometer. This section details the assembly of this configuration. 2.4.3.
pulseEKKO PRO 2.4.3.2 2-System Assembly and Startup Attaching the Big Wheel Odometer Figure 2-22: The big wheel odometer. Ensure that the small yellow odometer is tightly pressed against the rim of the wheel so that it spins when the big wheel is rotated. Figure 2-23: The big wheel odometer attaches to the skid plate assembly exactly the same way as the adjustable tow handle is attached. Place the T end of the odometer into the trough on the end of the skid plate assembly.
2-System Assembly and Startup 2.4.3.3 pulseEKKO PRO Connecting the Odometer Cable to the Control Module The Big Wheel Odometer comes with a long cable that extension to allow it to connect to receptacle 1 on the control module (Figure 2-24). The Big Wheel Odometer and odometer cable can be seen in the complete system configuration (See Figure 2-2 on page 3). Figure 2-24: The Big Wheel Odometer uses a long extension cable (not shown) to attach to receptacle 1 on the control module.
pulseEKKO PRO 2.4.3.4 2-System Assembly and Startup Connecting the Transducer Cables The next step is to connect the transducers to the control module. Figure 2-25: Connecting the transducer cables to the transducers. The connections are secured with latches. Figure 2-26: Connecting the transducer cables to the Control Module.
2-System Assembly and Startup 2.5 pulseEKKO PRO Adding Accessories There are several accessories that can be connected to the pulseEKKO PRO system. These include two types of beeper/triggers, odometers, GPS and the DVL Carrier. These are described below. 2.5.1 Electrical Beeper/Trigger Unit The Electrical Beeper/Trigger comes as a standard accessory with the pulseEKKO PRO system. To connect the electrical beeper/trigger unit, attach it to receptacle 2 on the control module (Figure 2-27).
pulseEKKO PRO 2-System Assembly and Startup Figure 2-28: Attaching the Fibre Optic Remote Beeper/Trigger unit to the transmitter handle. To connect the fibre optic remote beeper/trigger unit you should have the dual fibre optic cable for the control module to transmitter connection plus a short single fibre optic cable (Figure 2-29). One of the two cables on the dual fibre optic cable should already be connected to the Input (black) receptacle on the transmitter.
2-System Assembly and Startup pulseEKKO PRO Figure 2-29: Fibre optic cabling details for the Fibre Optic Remote Beeper/Trigger unit. The Fibre Optic Remote Beeper/Trigger unit is powered by one 9 Volt battery that slides into the battery compartment (Figure 2-30). Please note the proper polarity of the battery. An alkaline 9V battery will normally power the unit for 3-5 hours of heavy use so it is a good idea to have spare 9 Volt batteries available.
pulseEKKO PRO 2-System Assembly and Startup To turn the Fibre Optic Remote Beeper/Trigger unit on, depress the thumb lever on the top of the unit and hold it down for 3 seconds. The red light will come on and start to flash. After 3 seconds the unit will beep 3 times and the red light will stop flashing and stay on. This indicates that the unit is ready for data collection. To turn the Fibre Optic Remote Beeper and Trigger unit off, depress the thumb lever and hold it down for 3 seconds.
2-System Assembly and Startup pulseEKKO PRO The pulseEKKO PRO is designed to work with a number of different odometers. This includes the Big Wheel Odometer (See Figure 2-23 on page 17), the SmartCart odometer (Figure 2-32 below) as well as vehicle odometers available from Sensors & Software. The odometer has an electrical connection to receptacle 1 on the control module (Figure 2-32).
pulseEKKO PRO 2.6 2-System Assembly and Startup Starting the pulseEKKO PRO System 2.6.1 Powering the DVL and Control Module Connect the Control Module to Power Supply Cable to the receptacle labelled 3 on the control module (Figure 2-34) This cable will only fit on the number 3 receptacle. Note that the other end of this cable has an XLR connector. Power can be supplied to the DVL by using a battery (normally supplied by Sensors & Software) with the mating XLR connector.
2-System Assembly and Startup pulseEKKO PRO 2.6.2 Powering the Low Frequency Transmitter and Receiver Turn the transmitter and receiver ON by pressing the button on the top of each unit. The red Power LED on the top of the unit will flash 5 times and then stay on to indicate the unit is ready for operation. If not, check that the batteries inside the Transmitter and Receiver are fully charged and have been inserted the right way.
pulseEKKO PRO 2-System Assembly and Startup Brightness: The yellow Brightness control arrows are used to increase and decrease the screen brightness. Increasing the Brightness setting may improve the visibility of the screen in dark conditions. Contrast: The yellow Contrast control arrows are used to increase and decrease the screen contrast. Increasing the Contrast setting may improve the visibility of the screen on a bright, sunny day.
2-System Assembly and Startup pulseEKKO PRO The DVL can be shut down by pressing button number 5. Exit also serves an important function. Before exiting, the program saves all the current parameters. This process enables the system to start up with the same settings as before it was last powered off. Therefore, the user should NOT shut off the DVL by only removing the power.
pulseEKKO PRO 2-System Assembly and Startup MAIN MENU 2 System Setup 1 Run pulseEKKO GPR A-B Select Data Folder Number 3 View Setup 1 Transfer Directory 1 GPR Parameters A Up Antenna Frequency 1 Collect Line Data 5 Shut Down 4 File Management Time Window B Down A-B Select Line Number Sampling Interval 1 Tag 1 Run Antenna Separation 2 Send Antenna Step Size 8 Exit 2 Setup Menu (shortcut) Radar Velocity 8 Return 2 Transfer File System Stacking 1 Next Line Pulser Setting 2 Collect
2-System Assembly and Startup pulseEKKO PRO 2.6.5 Using the Software Menus Menu items can be selected in one of two ways: 1) If the menu item has a number listed beside it, that item can be selected by pressing the corresponding button number on the DVL. For example, in the above menu (See Figure 2-36 on page 27), pressing the number 1 will select the option for running a pulseEKKO GPR system.
pulseEKKO PRO 3 3-System Setup Parameters System Setup Parameters The System Setup option from the main menu (See Figure 2-36 on page 27) is used to set up the data collection parameters. Figure 3-1: The System Setup main menu is used to access and change any parameter used for data collection. Related parameters are grouped under different menu headings, for example, GPR Parameters list the variables specific to the GPR system.
3-System Setup Parameters pulseEKKO PRO Figure 3-2 illustrates how many parameters must be set before data collection can start. While intimidating, many of the parameters can use the default values while many others are rarely changed at all. 3.
pulseEKKO PRO 3.2 3-System Setup Parameters GPR Parameters Selecting the GPR Parameters menu option will display a screen similar to Figure 3-3. This section describes, in detail, each parameter listed in this menu. Figure 3-3: The GPR System Parameters menu. Use the Up and Down buttons to move to the desired parameter and edit the value by pressing the A and B buttons. Several of the parameters have suggested values, indicated by an asterisk (*), but these values can still be changed by the user.
3-System Setup Parameters pulseEKKO PRO 3.2.1 Antenna Frequency Deciding which antenna frequency to use for a survey depends on the objectives of the survey. As frequency decreases the depth of investigation generally increases but spatial resolution decreases. Therefore, the ideal survey will be one that uses the highest frequency that adequately penetrates to the target depth. This is not always easy to determine and often field experimentation with several different frequencies is necessary.
pulseEKKO PRO 3-System Setup Parameters 3.2.2 Time Window The Time Window setting determines how long (and therefore how deep) the radar system will probe the subsurface. It is important that it is set to a value appropriate for the depth of the survey target. An entire survey could fail if the window is not sufficiently long enough to sample to the depth of the target. Conversely, too long a time window increases the data volume and decreases productivity.
3-System Setup Parameters pulseEKKO PRO The wave velocity depends on the properties of the material. The Noggin software allows the user to input different velocities, which changes the total depth range displayed on the screen. A value of 0.1 m/ns (or 0. 33 ft/ns) is a good average value for geologic materials; a table of the velocities of common geologic materials is listed below (Section 3.2.6: P39). 3.2.
pulseEKKO PRO 3-System Setup Parameters 3.2.4 Antenna Separation As the transmitting and receiving antennas are moved along a survey line, it is important that a separation be maintained between them. When the antennas are mounted on a cart the antenna separation is fixed, but when the antennas are not fixed in position, it is common to use a rope or measuring tape to maintain the proper separation (See Figure 6-4 on page 84). This parameter is set under System Setup - GPR Parameters - Antenna Separation.
3-System Setup Parameters pulseEKKO PRO 3.2.5 Antenna Step Size This specifies the distance the antenna pair will be moved each time to collect a new trace during a Reflection mode survey (Section 3.4.5: P51). To properly resolve subsurface targets spatially, it is important that a proper Antenna Step Size be selected. Too coarse a Step Size may result in missed subsurface targets while too fine a Step Size will result in large data volumes and slow survey productivity.
pulseEKKO PRO 3-System Setup Parameters 3.2.6 Radar Velocity If an accurate depth axis on the real-time display is desired, or the user wishes to see the approximate depth of penetration while setting the time window value (Section 3.2.2: P35), the user should supply the program with the average radar wave propagation velocity (in m/ns or ft/ns). The best way to determine the radar velocity of the survey area is to extract the velocity using the Hyperbola Curve Fitting routine (Section 5.5.4.
3-System Setup Parameters pulseEKKO PRO 3.2.7 System Stacking In noisy environments, one way of improving signal to noise is to collect more than one trace at each survey position, averaging them and recording the averaged trace. This is known as “trace stacking” or “stacking”. Data quality improves because the noise, which is usually a random addition to the trace, tends to zero when averaged while the GPR signal is constant, thus increasing the “signal-to-noise ratio”.
pulseEKKO PRO 3-System Setup Parameters 3.2.8 Pulser Setting This setting allows the user to specify which transmitter (or pulser) is being used for data collection. Several different transmitters can be used with a pulseEKKO PRO system. In general, if you have a pulseEKKO PRO transmitter, set Pulser Setting to PRO Auto. This will automatically set the transmitter to the highest voltage available for that transmitter.
3-System Setup Parameters 3.3 pulseEKKO PRO Acquisition Control Selecting the Acquisition Control parameters menu option from the System Setup main menu (See Figure 3-1 on page 31), will display a screen similar to Figure 3-5. This section details each parameter listed in this menu. Figure 3-5: The Acquisition Control menu. Use the Up and Down buttons to move to the desired parameter and edit the value by pressing the A and B buttons.
pulseEKKO PRO 3.3.1.1 3-System Setup Parameters Triggers Triggering the system with an electrical, Fibre Optic or DVL B Button trigger (options 1 -3) is best for surveying in difficult terrain where antennas cannot be moved easily or at regular time intervals. For the position of each measurement point, the system assumes the operator has moved the antennas one step size along the survey line. This is also the mode to select when an odometer is used to trigger the system at specific distance intervals.
3-System Setup Parameters pulseEKKO PRO 3.3.3 Free Run Trace Delay When the system is run in Free-Run mode (Section 3.3.1.3: P43), this option allows the user can specify a time delay (in seconds) between traces. This delay allows time for the user to set up the antennas at the new position. The computer automatically collects the next trace after the elapsed time has passed. The Trace Delay is input in tenths of seconds, between each data collection point.
pulseEKKO PRO 3-System Setup Parameters The DVL can be set up to read and log GPS information collected during data acquisition with the GPR system. GPS information can be logged in two different ways: 1) For every trace collected by the GPR system, or 2) Every time the user adds a fiducial to the data by pressing the Fiducial button or the A button (Section 5.4: P72). This feature provides a means of capturing GPS information to an independent file.
3-System Setup Parameters pulseEKKO PRO Trace #85 $GPGGA,134850.00,4338.204868,N,07938.429003,W,2,06,2.1,152.60,M,-35.09,M,4.2,0118*74 $GPVTG,152.6,T,,,002.3,N,004.3,K,D*43 $GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.7*37 F1 $GPGGA,134850.00,4338.204868,N,07938.429003,W,2,06,2.1,152.60,M,-35.09,M,4.2,0118*74 $GPVTG,152.6,T,,,002.3,N,004.3,K,D*43 $GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.7*37 Trace #86 $GPGGA,134851.00,4338.204362,N,07938.428362,W,2,06,2.1,152.40,M,-35.09,M,5.2,0118*72 $GPVTG,136.
pulseEKKO PRO 3-System Setup Parameters $GPGSA,A,3,04,30,10,13,24,06,,,,,,,3.2,2.4,2.1*32 F2 $GPGGA,134301.00,4338.192559,N,07938.449176,W,2,06,2.4,153.17,M,-35.09,M,5.0,0118*7A $GPVTG,314.4,T,,,000.6,N,001.1,K,D*41 $GPGSA,A,3,04,30,10,13,24,06,,,,,,,3.2,2.4,2.1*32 F3 3.3.4.2 Baud Rate The baud rate is the speed that data is sent from the GPS receiver to the serial port of the DVL. The available options are: 2400, 4800, 9600 (default) or 19200. Often, the baud rate for GPS units is 4800.
3-System Setup Parameters 3.3.4.7 pulseEKKO PRO Test GPS with Listing After all the settings above have been input and the GPS receiver is attached to the serial port on the DVL, the test option allows the user to check that the DVL is receiving the GPS output. If the NMEA strings are successfully being read by the DVL they will appear on the DVL screen. This is a good time to note the prefix of the last NMEA string in the list and input it in the End String setting above.
pulseEKKO PRO 3.3.5.2 3-System Setup Parameters Set Odometer Manually When Odometer Calibration is selected, the user is prompted to manually enter the odometer calibration factor. In general, this method of odometer calibration is not recommended because it will not be as accurate as calibrating the odometer over a known distance. 3.3.5.3 Odometer Direction This setting determines whether data are collected as the system is rolled forward or reverse. The back up arrow (Section 6.6.
3-System Setup Parameters 3.4 pulseEKKO PRO Survey Parameters Selecting the Survey Parameters menu option from the System Setup main menu (See Figure 3-1 on page 31), will display a screen similar to Figure 3-8. This section details each parameter listed in this menu. Figure 3-8: The GPR Survey Parameters menu. Use the Up and Down buttons to move to the desired parameter and edit the value by pressing the A and B buttons. 3.4.1 Start Position This is the starting position for the first trace.
pulseEKKO PRO 3-System Setup Parameters 3.4.4 Data Directory Number This option is used to determine the directory that the data files will be saved to. The idea is that related data files are saved in the same directory. The Data Directory Number can be changed in this menu or under the Run pulseEKKO menu (Section 5.1: P69). The user has access to 20 different directories for data storage. 3.4.5 Survey Type Ground penetrating radar has been used in many different survey modes to gather information.
3-System Setup Parameters pulseEKKO PRO X Lines Only Set up a first-quadrant XY grid. Data lines run in the X direction, distance increasing from the Y axis baseline. Line numbers increase in the positive Y direction (see Figure 3-9). Lines must be equally spaced. It is not critical that all the lines are the same length. However, it does make processing easier if all the lines start at the same baseline position (usually defined as zero (0.0)).
pulseEKKO PRO 3-System Setup Parameters Y Lines Only Set up a first-quadrant XY grid. Data lines run in the Y direction, distance increasing from the X axis baseline. Line numbers increase in the positive X direction (see Figure 3-10). Lines must be equally spaced. It is not critical that all the lines are the same length. However, it does make processing easier if all the lines start at the same baseline position (usually defined as zero (0.0)).
3-System Setup Parameters pulseEKKO PRO X and Y Lines Set up a first-quadrant XY grid. X data lines run in the X direction, distance increasing from the Y axis baseline. Line numbers increase in the positive Y direction (see Figure 3-11). Lines must be equally spaced. Y data lines run in the Y direction, distance increasing from the X axis baseline. Line numbers increase in the positive X direction. Lines should be equally spaced. The line spacing of the X lines and Y lines can be different.
pulseEKKO PRO 3-System Setup Parameters 3.4.7 X Line Spacing For X Only or XY grid data acquisition, the distance between the X survey lines needs to be specified in this menu (Figure 3-9 and Figure 3-11). The distance units are assumed to be the same as those specified in Positional Units (Section 3.4.3: P50) If an XY grid is being collected, note that the line spacing of the X lines and Y lines can be different. 3.4.
3-System Setup Parameters 3.5 pulseEKKO PRO Display Parameters Selecting the Display Parameters menu option from the System Setup main menu (See Figure 3-1 on page 31), will display a screen similar to Figure 3-12. This section details each parameter listed in this menu. Figure 3-12: The Display Parameters menu. Use the Up and Down buttons to move to the desired parameter and edit the value by pressing the A and B buttons. 3.5.
pulseEKKO PRO 3-System Setup Parameters Figure 3-13: Grey scale traces depict the signal amplitude as shades of grey from white to black. Data traces can be plotted to the screen with a width of 1 pixel (top left), 2 pixels (top right), 4 pixels (bottom left) or 8 pixels (bottom right). The narrower the trace width, the more data that can be plotted on one screen.
3-System Setup Parameters pulseEKKO PRO 3.5.2 Gain Type Applied and Gain Applied Since the radar signal strength normally decreases with increasing time, it is usually necessary to apply some sort of gain function to boost the weaker signals at later times. The raw, ungained data shows little signal except for the strong near-surface reflectors (Figure 3-15). No gain may be useful in areas where the radar signal is very strong or in areas where the targets are very shallow.
pulseEKKO PRO 3-System Setup Parameters Figure 3-16: Shows how the AGC function (middle) is inversely related to reflector strength of the raw trace (top). The AGC gained trace (bottom) is a result of multiplying each point in the raw trace with the equivalent point in the AGC function. Figure 3-17: Display of a data section over buried tanks. An AGC gain was applied before plotting. The only user variable for the AGC gain is the Max Gain Applied value.
3-System Setup Parameters 3.5.2.2 pulseEKKO PRO SEC Gain The SEC (Spreading & Exponential Compensation) gain is a composite of a linear time gain and an exponential time gain. This gain compensates for the spherical spreading losses and the exponential dissipation of energy in the data being collected. Since radar data is attenuated exponentially and the SEC is an exponential gain (Figure 3-18), it tends to be the gain closest to physical reality.
pulseEKKO PRO 3-System Setup Parameters Figure 3-20: Display of a data section over buried tanks. An SEC gain was applied before plotting. The only user variable for the SEC gain is the Alpha Gain Applied value. This quantity represents the radar wave attenuation given in decibels/metre. A typical value is 0.5 to 5. 3.5.2.3 Constant Gain This routine will apply a constant gain factor to the input data set. The only parameter required is the constant factor to multiply all data points by.
3-System Setup Parameters pulseEKKO PRO Figure 3-21: Display of a data section over buried tanks. A Constant gain was applied before plotting.
pulseEKKO PRO 3.6 3-System Setup Parameters DVL Setup Menu 3.6.1 Set DVL Time and Date The date and time are saved with the data files. The DVL date and time setting can be changed by moving to one or more of the appropriate fields and editing the current setting. The LEFT and RIGHT arrows are used to move between fields. To change any of the numbers or months, use the UP and DOWN arrows to increase or decrease the value. When the desired date and time are set, press ENTER to save the changes.
3-System Setup Parameters pulseEKKO PRO 3.6.4 Select Display Info Mode The Display Info Mode refers to the messages written to the screen at the start of data collection. When the user presses the Start button to acquire a line of data, the system must set up communications between the various system components and initialize them. During this process, messages are written to the screen. The Display Info mode determines the level of message detail.
pulseEKKO PRO 4 4-Running in Scope Mode Running in Scope Mode Once the System Setup parameters have been set, data collection can begin by selecting 1 - Run pulseEKKO GPR from the main menu. The screen shown in Figure 4-1 will be visible. Turn on the transmitter and receiver and ensure that they are fully powered and initialized by checking that the Power LED on the top of the unit has stopped flashing.
4-Running in Scope Mode 4.1 pulseEKKO PRO Scope Screen A sample of a screen data plot while in Scope mode is shown in Figure 4-2. The radar amplitude (in millivolts) is plotted in the vertical axis while the time axis is plotted in the horizontal axis. The length of the time axis depends on the Time Window value. Each division in the time axis is 10% of the length of the Time Window. In the case shown in Figure 4-2, the Time Window is 100 ns so each division is 10 ns wide.
pulseEKKO PRO 4-Running in Scope Mode Figure 4-3: Timezero or the first break is the first large deflection in the trace. Ideally, timezero needs to be shifted to the start of the second vertical division as shown in Figure 4-2. Use the Auto <> button to try and automatically locate timezero and set it to the correct position. The Shift > and Shift < buttons can be used to move timezero to the right and left respectively.
4-Running in Scope Mode pulseEKKO PRO Shift > and Shift < are used if the transmit pulse is visible on the screen but needs to be moved into the ideal region (Figure 4-3). The Shift button will change to reverse video when selected and the pulse will step across the screen in the direction indicated. Pressing the Shift button again will deactivate the shift and stop the pulse. The percentage value (1%, 5%, 10% and 25%) determine the amount that the pulse is shifted in each step.
