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The dipole cables are a high failure item as they are subjected to considerable wear and tear. Here are some steps that you can take to prolong the life of the System: Never lift the transmitter or receiver by the pulling on the Dipole cables. While setting up the System, it is extremely important to remember that the transmitter and receiver can easily slip out of the white neoprene covers if you are not paying attention. This will cause them to hit the ground and break the yellow connector, or at the very least jam foreign debris into the connector. A good habit to get into is to carry the units with the nose (cone shape) pointed down, that way they cannot slip out of the neoprene cover. Do not put undue stress by pulling on the System at angles greater than 45 degrees at any given point in the array. Always make broad turns or pick up the array to start a new line. Make sure that the transmitter and receiver are always facing the direction of travel. (The cone pointing towards the console/operator) This will eliminate the possibility of turning the array into a "plow" and placing excessive strains on the connectors, not to mention communication problems. By following these instructions you will find that the instrument's connectors will be able to withstand the strain incurred during normal usage. Of course there may be circumstances that make this difficult, but it is good to be aware of these issues.

Since the MagArrow Magnetometer only weights 1 kg it will little impact on your 3-5 kg payload drone flight time. Our MagArrow uses a MFAM sensor to provide high quality magnetic data with noise/sensitivity range of only 5 nT. Most people have suspended the System with non-magnetic cables to remove the magnetometer from the magnetic influence of the drone itself. Some customers have decided to build a fixed frame to mount the System but generally it isn’t large enough to remove the magnetometer from the drone’s magnetic effects so there will need to be advanced filtering to compensate the magnetic field readings. Either option is acceptable.

The time associated with each data point in a SEG-2 data file generated by a Geode is related to the time of the “trigger” event which was instrumental in the production of the file and its content. The Trigger Master and Trigger Distribution The trigger event occurs at the Geode designated within the Controller software as the Trigger Master. Although all Geodes are capable of being Trigger Masters, there must be one and only one Trigger Master in any properly functioning Geode System. The Controller automatically takes care of this requirement when the designation is made by a user, and when the System is established at the time of Controller start-up based on a previous designation (or a default setting in the case of a “new survey”). All other Geodes in the System will have their Trigger Master circuit disabled. A trigger event can be initiated by an external electrical pulse provided to the trigger input connector of the Trigger Master Geode, or by a command sent via Ethernet from the Controller to the Trigger Master (usually for test purposes), but only when all conditions are satisfied to allow data recording. There is also a special trigger initiation situation, called “self-triggering” which will not be discussed further here. Upon acceptance of a trigger event, the Trigger Master will distribute the trigger signal to all Geodes in the System, itself included, via an RS-485 network that resides within the digital interconnect cabling. (Proper termination of this RS-485 network is automatically taken care of by the Controller.) The trigger signal is propagated through the cabling and Geodes at the nominal speed of 70% of the speed of light, or approximately 2.1x10^8 m/sec. The maximum distance of successful propagation depends on a number of factors such as the number of Geodes involved, the noise environment, the quality of the cables, and the acceptable amount of timing uncertainty for the particular application. Distances approaching or exceeding 1km should be given careful attention in this regard. In a 3-D Geode System involving LTUs, each LTU, unlike a Geode, will reconstruct the trigger signal before sending it on, effectively confining the maximum distance issue to each sub-network separated by LTUs. The penalty is an additional delay of about 100nS for each LTU in the route. The External Trigger Circuit The external trigger input is capacitively coupled, with a 2mS time constant, to the midpoint of a resistive voltage divider. The voltage difference between the two ends of the divider constitute a voltage "window", which size is set by the trigger sensitivity parameter and can range from essentially zero at the highest sensitivity, to about +/- 2.5V at the lowest sensitivity. The Geode will trigger (if enabled) if and when the coupled signal exceeds the window, in either direction (i.e., positive or negative going). The signal, after the capacitor, is clamped by diodes to the range between the trigger signal ground and +5VDC. The trigger detector output is disabled when the System is disarmed, during a parameter change, and during a shot, up to the trigger hold-off time after the end of the shot. The trigger hold-off time is a parameter set by the user. Preceding the coupling capacitor (i.e., essentially the node accessible at pin A of the external connector), there is a 3.3K-Ohm pull-up resistor to +5VDC (relative to pin B). Also a fast transient suppressor clamps the input at about +/-14VDC. It is advised that the DC + AC level of any voltage applied to pin A relative to pin B be kept within the range of +/-7V, giving some margin of safety. If a DC voltage somewhat less than +5VDC is applied when the connector is first mated, the instrument may trigger at that moment. But, subsequently, because of the capacitive coupling, it will trigger on the next positive or negative going pulse that exceeds the window level. If the duration of the applied voltage pulse is less than the record length + delay time + hold-off time, then the Geode will effectively be ready to trigger on the same edge of another similar pulse. Sub-sample Synchronization The Geode supports a sub-sample timing synchronization feature used for synchronizing the data acquisition after a trigger event to the distributed trigger signal, so that subsequent time points will be known to within 1/32 (~1/20 at the fastest two sampling rates) sample interval. It does this by increasing the sample interval at the trigger time by 0 to 31/32 of a sample interval in increments of 1/32, so that the first sample after the trigger would represent a time of one sample interval after the trigger event, with a tolerance within 1/32 of a sample interval. The following samples continue from there at the expected intervals. For example, with a selected sampling interval of ¼ mS and a recording delay of 0mS, the first sample in the recorded file for each channel would represent data at 250 to 258uS after the trigger event. This of course potentially introduces a small discontinuity at the time of the trigger, observable depending on the nature of the channel waveform(s). (The zero-phase anti-alias filter will smear the discontinuity into the nearby samples both before and after, consistent with the bandwidth of the filter.) Sub-sample synchronization can be disabled if it is deemed to be detrimental for the particular application, at the expense of losing the 1/32 interval timing accuracy. Timing Errors The principal errors in Geode timing are of two types: those associated with the trigger mechanism and which are static over the duration of the record, and those associated with the time base and which change over the duration of the record. Excluding the trigger propagation delay mentioned above, the trigger timing uncertainty is about 1uS. The known fixed errors have been lumped together and are reported in the SEG-2 file trace headers as channel SKEW. (The actual channel skew is zero, since all channels are effectively sampled simultaneously, but the SKEW value in the header is used as the only place permitting small timing corrections. Note that the SKEW value for every channel is identical.) If the size of this correction is important to the application, the SKEW value should be added to the calculated time points when the data is being processed. The Geode time base has a +/-15ppm stability over temperature (-20C to +70C) and component variations. Thus time drift relative to absolute time and relative to other Geodes is possible. (However, all channels within any Geode enclosure use the same time base, so there is no relative drift between channels in the same enclosure.) Therefore timing uncertainty increases from that existing at the time of the trigger until the time of the next trigger (or end of record). Special Timing Issues Involved with “Continuous” Recording “Continuous” recording is a method that allows unending 100% time coverage with recorded Geode data. It produces a series of time-overlapped records created by the use of a negative time delay set equal to the record length such that each record consists of completed history at the time of the trigger event. This technique circumvents the problem of data transmission overrunning data acquisition. The principle constraint is that the cycle time from trigger to trigger must always be less than the chosen record length. Otherwise, gaps rather than overlap would result. Commonly it is used with GPSderived triggering in order to provide time-stamping of each trigger event. Upon consideration of the above, it will become clear that the time-stamp associated with a particular trigger event will pertain to the data in the following record, not to the data in the record in which the time-stamp is written. This comes about because the trigger event ends the record. Because there is data overlap between records, the precise trigger point in the following record at which the time-stamp applies can be found by comparison of the data values at the end of the former record with those near the beginning of the subsequent record. The overlapping data will be exactly identical in both records (since they are read from the same memory location, twice). The earliest data in the subsequent record that goes beyond the data of the previous record is the data that is one sample interval (assuming sub-sample synchronization is enabled) past the time-stamp. Note well that this comparison must be made independently for at least one channel of each 8-channel Geode board set, because the discrete time at which data values are written to the memory buffer, relative to the trigger event, is a function of each individual board set in the Geode System. Correct GPS Time-Stamping There are differences between various GPS models that can affect accurate time stamping. The 1PPS signal from a GPS has a “timing edge” and return edge, of which only the former is the true whole-second edge. Some models use a rising edge as the timing edge, some the falling edge, and some have it selectable. Consult the GPS manual to determine the definition of its timing edge. As indicated earlier, the Geode can be triggered on either a rising or falling edge. It is important to insure that the Geode is being triggered on the proper edge in order to avoid timing that may be a fraction of a second off. This is expanded upon below. Some GPS units provide a very narrow timing pulse, others one that has a nearly 50/50 duty cycle. For the narrow pulse units, almost certainly it is the leading edge (rising or falling) that is the “timing edge”. This case can be easily handled by using the Geode Trigger Hold-off feature. If a 10-second cycle time is desired, set the Trigger Hold-off time to about 9.5 seconds. In this case, there is a very small chance that the very first trigger could occur on the wrong (trailing) edge, but from then on the leading edge will be used as the triggering edge. If the GPS provides a 50/50 duty cycle edge, and it is not alterable, then the Geode by itself could as easily start on the wrong edge as on the correct timing edge, and continue thusly until restarted. For this case, Geometrics can provide a Trigger Timing Interface Box (TTIB) that will correct the situation. The TTIB can be programmed to respond only to the correct edge (rising or falling), change the polarity if needed, and gate through only one of every N 1PPS pulses, where N is programmable. (The TTIB also incorporates an alarm System that can provide a remote alert if a record is missed.) Another potential issue comes from the variations between GPS models of the time that the serial time string (containing the time value of the associated 1PPS) is issued relative to the 1PPS itself. The Geode Controller attempts to pick the correct serial string based on a calculation involving the known record length, the PC times, and the trigger notification message from the Geodes. But if the GPS issues the serial string at an unusual time (and the time has been seen to vary somewhat with a given GPS unit) then it could pick up the incorrect time, off by 1 second. If rare, it can be subsequently detected and corrected during data processing, but if consistent it may not be easily detected. Again, the TTIB can accommodate the situation by only gating through to the Controller PC the string belonging to the gated-through 1PPS pulse. The Controller Serial Input Time Window can then safely be widened to 2 seconds (assuming the cycle time is more than 2 seconds) if need be, to expand the Controller’s search for the string around the calculated trigger time.

The OS software requirements are provided which each release of the software when filling out the ECR/ECO. Those requirements depend on the version released. Over the last 25 years these requirements have changed. The software only supports Windows. We do not support Linux. The last version of the SCS software support all 32-bit and 64-bit of Windows since Windows 7. Windows servers are excluded, since they have not been tested, but should work. The hardware requirements are more complicated as it depends on the type of seismic survey, number of channels and software product SCS (SGOS, MGOS, ESOS, ...), SAS and options. It also depends how many network cards are needed, sample rate, and record length. For small Systems, SCS will require at a minimum 512MB of free memory. For large Systems up to a Maximum of 2GB of free memory. The CPU follow the same pattern. Any CPU since Pentium 90, if supported by the OS, will work for small Systems. A bigger survey System and continuous recording software may need i5 or i7 type CPU. An SSD drive may also be needed. See SCS software license agreement.

Key components include: Seismograph (Geode Seismograph) 12V Battery PC (required for Geode and ES-3000) Digital cables (Geode and ES-3000) Geophones (including spares) Geophone cable(s) Source (hammer, weight drop, explosives) Striker plate (if using hammer) Hammer switch and spare Trigger extension cable Measuring tape Hand level Hearing protection (IMPORTANT)

Channel Remapping Channel remapping allows you to change: the order of channels on each analog spread cable that connects to the Geode reorder the Geode boxes. You would use this option if your cables were wired opposite to the default order normally used in Geometrics wiring, if you wished to turn your line around to have the low channels at the opposite end, or if your cables had a wiring error. Channel remapping is also often necessary when using more that a single network cable. Default cable wiring of Geometrics seismographs Default order is defined as the natural electrical order in which channels are oriented when the System first powers up before remapping. Refer to Section 3 under Connector Wiring that discusses standard wiring configurations. You may have requested a custom wiring configuration from Geometrics. If you are confused about your wiring, contact the factory and refer to the serial number and job number. Geode cables are typically wired in a ‘high-side configuration’, meaning that the Geode connects closest to the highest numbered channel on the analog cable. The 149 figure above shows this configuration for a single box System, with 24 channels. Multiple Geodes The following diagram shows a default single digital line (one network card) System with 3 Geodes. Note that Geode one is always closest to the controller in a default configuration. Multiple Network Lines The next diagram below shows a default configuration with two digital lines (two network cards) with the controller positioned in the middle. Line 1 is on the left and line 2 is on the right. One might use two lines to increase data throughput to reduce time between shots. Like the configuration above, the Geodes are numbered starting closest to the controller. The seismic controller software labels all of the channels contiguously even though they are on two separate digital lines. However, if the lines are collinear, the first line will have the channels ordered backwards. This can be easily rectified with the remapping feature. There are two ways of remapping channels: automatic mode and manual mode. Automatic mode settings are listed on the top of the remapping dialog box, and manual mode on the bottom. Automatic Channel Remapping Automatic channel remapping allows you to reverse either the order of the Geodes on the line, or reverse the order of the channels on the spread cable. The above diagram shows the result after both channels and Geodes have been reversed, renumbering the line so that low channels start on the left hand side and increase towards the right. In the dialog box, the automatic remapping boxes referencing line 2 remain unchecked, since the default orientation on line two was correct. Manual Channel Remapping Channels can be remapped on an individual basis using the Manual Map Mode. Select the appropriate check box, and enter the order in which you would like the channels that differs from the default order. You can specify individual channels separated by a comma (1, 3, 4, 6 etc) or a range of channels (1-13, 24-14 etc). For example, if you wanted the channels ordered backwards on a 24-channel System, you would enter 24-1. If you wished to reverse the order of channels 1- 12 in a 24 channel System, you would type 12-1, 13-24. Other examples are shown opposite, and are available by pressing the See Examples button on the remapping menu.

1. Hook up Geode in normal configuration to computer Ethernet box. 2. Select Start New Survey. 3. Uncheck Line Tap. 4. Uncheck Aux. 5. Select YES to all pop up menus. 6. Locate lower left corner menu: Seismodule List Window. 7. Note what current loader version under LDVER column of table in Seismodule List Window. (Ex. 2.729) 8. In order to change the LDVER, you must first set up the table in column F from N/A to X by doing the following: 9. Select System pull down menu from the upper task bar. 10. Select Test. 11. Select Update System Board Bios. 12. Select I Agree. 13. Select Browse. 14. To set up table to enable loader version update (LDVER) select the file: GEODEFOR3D-1.0.exe. 15. Select Open. 16. Select Start Burning. 17. Select Yes. 18. Cycle power or shut down controller by using the software. 19. Restart the Geode. 20. Repeat necessary steps to get to Seismodule List Window. 21. Verify value in column is now X. 22. Select System pull down menu from the upper task bar. 23. Select Test. 24. Select Update System Board Bios. 25. Select I Agree. 26. Select Browse. 27. Select from Flash Update File Flash3_703&2_42.exe. 28. Select Start Burning. 29. Select Yes. 30. Verify Power LED light on Geode now blinks 3 seconds on 1 second off. 31. Select OK. 32. Cycle power or shut down controller by using the software.

The MFAM Magnetometer samples at 1000 Hz, which in turns captures a lot of unique waveforms. When viewing the data raw, it can therefore appear to be a bit noisy. But a closer examination of the data will reveal a real variation of the magnetic field which is caused caused by the power distribution network. Proper filtering is required to reduce the power line caused variations and reveal the strong signal of interest. It is not obvious that 60 or 50 hertz electromagnetic radiation is real, since in ordinary experience any power line “noise” is electrostatically coupled into a System (think 60 hertz hum on a stereo System) and is a fault that needs to be fixed. In this case however the variation in the magnetic field is induced by the power grid and is real. The magnetometer is simply and dutifully reporting the variation. These power line variations are to some extent present everywhere – even miles from the nearest power line. But obviously being close to power lines will increase the amplitude of the variations a lot. Often on a MagArrow survey the power line variations will be larger at one end of the survey area than the other. Poking in the GPS coordinates at the survey area nearest the larger variations into Google Earth will usually reveal the power lines from an aerial view – even if they are not visible on the ground. After applying a Fourier Frequency Transform on the MFAM data to identify the noise sources, 50 and 60 Hz noise amplitudes are easily observed. Also observable is the likely to be 20.8 Hz Schumann resonance of the third node and some other ultra-low frequency electro magnetic radiation produced naturally by the Earth. Harmonics of 60 Hz are also present. Another common question is “Why is the power line variations not a sine wave like the power line voltage?” Remember that voltages do not make magnetic fields. Only current generates magnetic fields, and the current being drawn is not a sine wave at all. Many loads, for example, only draw current at the voltage peaks. This makes for a non-sinusoidal magnetic field that is rich in harmonics. Also note that most power distribution System use a 3 phase topology. The ripple current in such a System will be 150 or 180 Hz. Thus you will often see large peaks in the power spectrum at these frequencies and their harmonics.

The MFAM Magnetometer samples at 1000 Hz, which in turns captures a lot of unique waveforms. When viewing the data raw, it can therefore appear to be a bit noisy. But a closer examination of the data will reveal a real variation of the magnetic field which is caused caused by the power distribution network. Proper filtering is required to reduce the power line caused variations and reveal the strong signal of interest. It is not obvious that 60 or 50 hertz electromagnetic radiation is real, since in ordinary experience any power line “noise” is electrostatically coupled into a System (think 60 hertz hum on a stereo System) and is a fault that needs to be fixed. In this case however the variation in the magnetic field is induced by the power grid and is real. The magnetometer is simply and dutifully reporting the variation. These power line variations are to some extent present everywhere – even miles from the nearest power line. But obviously being close to power lines will increase the amplitude of the variations a lot. Often on a MagArrow survey the power line variations will be larger at one end of the survey area than the other. Poking in the GPS coordinates at the survey area nearest the larger variations into Google Earth will usually reveal the power lines from an aerial view – even if they are not visible on the ground. After applying a Fourier Frequency Transform on the MFAM data to identify the noise sources, 50 and 60 Hz noise amplitudes are easily observed. Also observable is the likely to be 20.8 Hz Schumann resonance of the third node and some other ultra-low frequency electro magnetic radiation produced naturally by the Earth. Harmonics of 60 Hz are also present. Another common question is “Why is the power line variations not a sine wave like the power line voltage?” Remember that voltages do not make magnetic fields. Only current generates magnetic fields, and the current being drawn is not a sine wave at all. Many loads, for example, only draw current at the voltage peaks. This makes for a non-sinusoidal magnetic field that is rich in harmonics. Also note that most power distribution System use a 3 phase topology. The ripple current in such a System will be 150 or 180 Hz. Thus you will often see large peaks in the power spectrum at these frequencies and their harmonics.

Hello, I wanted to try our MagEditor software, but it didn't accept any of the files I converted to 10 Hz, 20 Hz, 50 Hz, 100 Hz, and 1000 Hz CSV formats from Survey Manager. What's the reason and how can I fix it? My operating System is Windows 11 Home Single, and my computer specifications are:Processor: Intel(R) Core(TM) i9-14900HX (2.20 GHz)Installed RAM: 32.0 GB (usable: 31.6 GB)System type: 64-bit operating System, x64-based processor.

What Affects Geode Trigger Cycle Times? If you're trying to optimize your Geode System for faster trigger cycles—especially in high-repeat environments—there are a few key factors to consider. The goal is to ensure that the System completes its entire cycle (trigger → recording → data transfer → re-arming) before the next expected trigger. Here’s what influences that cycle: 🧠 Core Factors That Affect Cycle Times 1. File Size (Sampling Parameters) Your sample interval and record length directly affect the size of each data file.You can view the resulting file size in the Acquisition Parameters menu.Larger files take longer to transfer, which delays the re-arm process. 2. Data Transfer Rate The Geode typically transfers data at around 450–465 kb/sec.Reducing file size is the best way to reduce transfer time and speed up the cycle. 3. Calibration Frequency By default, the System may attempt to calibrate every N shots, which takes additional time.Go to Options > Calibration and set "calibrate every N shots" to a large number (e.g., 100000) to prevent unnecessary delays. 4. Recording Delay and Record Length If you're operating in a region with a consistently deep seafloor, you can add a recording delay and reduce record length accordingly.Example: If the water column is always >0.3s, you can apply a delay of 0.2s and reduce record length by the same amount.This trims your file size and speeds up the transfer/re-arm process. ⚙️ Best Practices Use the Auto-Trigger function or set trigger sensitivity to the maximum value for testing.Monitor the cycle timing and adjust acquisition parameters to stay within your trigger window.It's often an iterative process to find the ideal configuration for your environment.

Our seismographs do not require periodic calibrations in that they do not have any adjustable parameters. With that being said, we do recommend that they are checked for performance and routine maintenance to include intensive analog tests of the acquisition circuitry. A reasonable interval would be around every 5 years for normal usage. During these tests we verify that the seismograph analog performance meets our specifications by using a seismic test System. This System incorporates a standard reference oscillator and precision resistor networks to inject known signals into the seismograph. We then use algorithms in our software to calculate the response and performance of the analog circuits. This "performance test" is run whenever we receive an instrument in for repair or evaluation. Some of our customers do prefer to have the performance of their instrument checked on a periodic basis especially if they are required by their clients, for example the NRC. We offer these nontraceable recertification’s to include a calibration certificate and test results for a fee of $300. If you would like us to perform performance verifications and a System evaluation please reserve an RMA and obtain shipping instructions.

If the System has a large amount of survey data, it may affect the data transfer rate. Sometimes a very slow SD card makes the System unresponsive; to the user this can look like a slow/bad network connection. Therefore, it might be useful to clean up the SD card and USB drive. Delete the Geometrics.log file on the USB drive. Clean up the survey data on the SD card: First, make sure that you have all the data that you need off of the SD card. Either download all survey data that you want to keep, or copy all of the contents of the SD card to another drive (perhaps to a PC). Delete all of the data on the SD card, doing one of the following: Use the UI to delete all of the surveys, then use the "Clean old files" button on the Admin page to empty the recycle bin on the SD card. This can be VERY slow, and because the MagArrow has a very simple web interface, the user will get no useful feedback. On a very full SD card, this process might take 30 minutes or so. Or.... Remove the SD card from the MagArrow and after copying any data that the user still hasn't saved to a PC, format it or delete everything on it, then re-insert it. Be careful not to lose the SD card or to let it drop into the inaccessible spaces in the instrument. If you format the SD card, the ExFAT format is preferable. If the customer can't get the data downloaded from the instrument (takes too long or stops), the data can be imported into a survey in Survey Manager, directly from the SD card (or from the PC hard drive to which the SD card data has been copied). Then the SD card can be cleaned up or formatted. With the new version of Survey Manager (you need to update that also, not just the instrument software), the user can import a large survey, including all of the files in subdirectories, by selecting the "acquinfo.txt" file in the root directory of the survey, from the SD card. More details about how to import/export SD card files using Survey Manager can be found in the post below: SD card files conversion

General information The most common symptoms of intermittent connection issues are shown below: D_CY shows a background decay signal is either much higher than normal, and/or C_CY is a flat line (doesn’t decay). Figure 1 Intermittent connection issue. Where is the failure occurring? The two most common places where intermittent issues occur are at the two ends of the Rx cable: the joint between the Rx cable and the Cart and the joint between the Rx cable and the EDA box (orange box). Now we need to identify which joint has the intermittent issue. Set up the MM2x2 in DAM mode. Collect DAM data while keeping the Cart stationary but tapping one joint. Collect another DAM data while tapping the other joint. Analyze the DAM data by plotting the “Monostatic_5” for all 12 Rx channels in Geosoft. The channels having intermittent issues will appear much noisier. If you have MatLab software, you can download the MatLab code to analyze the DAM data. Example plots are shown below. It is obvious that “ZA” channel has the intermittent issue in Figure 2 and “XB” channel is open in Figure 3 (very flat line, no noise at all). Click here to download the code: Attachment : Intermittent_noise_full.zip . If both DAM and IVS data have the same problematic channel(s), we are confident that the intermittent issues observed in IVS data are repeated in DAM data, and by tapping at that location, we are able to identify the intermittent joint. Figure 2 Intermittent "ZA" channel. Figure 3 Open "XB" channel. What to do next? Disconnect the problematic joint and clean the connectors on both sides thoroughly (using an acid brush and a can of compressed air). Reconnect and try the tapping method again. If the problem goes away (no more noisy channels), the intermittent issue is likely caused by dust. If cleaning doesn’t fix the problem, swap out the Rx cable and repeat the tapping method. If the problem goes away, it is likely caused by a bad Rx cable. If there is another set of EDA and Cart available, swap out the EDA and the Cart to identify the problematic part. If not, use the tapping location to identify the problematic part. Fill out the RMA form at . If it is the Cart, send in the whole System for inspection/repair. You can contact Geometrics for MM2x2 rental if you need to continue your work during the down time. If it is the EDA, we recommend sending in the EDA only. It will save your repair time since it is much faster to unpack/pack/ship the EDA than the whole System. You can contact Geometrics for EDA rental if you need to continue your work during the down time. Warning Please note that this tapping method should ONLY be tried when intermittent issues have been observed in IVS tests. It is NOT recommended to use it as a daily QC test because it does put extra stress on connectors and likely leads to a shortened connector lifetime if applied too often.

Altitude refers to Meters Above Mean Sea Level. For both MagArrow I and II, the altitude is ellipsoidal and the earth model is WGS84. For additional information: Overview Reported elevations from MagArrow (and G-864 and MagEx) are the unedited values from the elevation field in the GNSS's GGA NMEA string. That value is the GNSS's calculated height above geoid; height above geoid is the standard meaning of the elevation field in the GGA NMEA string. But what does calculated height above geoid mean? Definitions GNSS - Global Navigation Satellite System GPS - The GNSS operated by the United States. Other Systems include GLONASS(Russia), Galileo (Europe), BeiDou (China), QZSS (Japan), IRNSS (India). Ellipsoid - A comparatively simple or abstract geometric model of Earth's surface. Geoid - A more complex model of Earth's surface that takes the place of what was previously called Mean Sea Level. At any particular latitude or longitude, the geoid's surface may be above or below the ellipsoid's by as much as a few hundred meters, depending on regional and local geography and geology. Reference datum - A specific model of Earth's shape (such as WGS84, EGM96...), including references to specific landmarks. Calculations A particular GNSS, for example the GPS System run by the United States, provides timing data to a receiver to calculate the receiver's position above or below a particular latitude and longitude on the surface of the ellipsoid. The GNSS receiver first uses that timing data to calculate its height over the ellipsoid, and then subtracts from it the local height of the geoid over the ellipsoid (or HAE), to arrive at the local height of the receiver over the geoid (or in old-fashioned terms, elevation over mean sea level): h - calculated height above geoid. This is the value reported in the GGA elevation field. H - height of the receiver over the ellipsoid (calculated from GNSS timing signals) N - local height of geoid over the ellipsoid, or HAE, per a lookup table or other local reference. h = H - N      Because the local height of the geoid over the ellipsoid is not provided by the GNSS, it must be provided locally, i.e. by the GNSS receiver, which may contain an internal database from which the local geoid height over ellipsoid (or HAE) can be found, based on the receiver's latitude and longitude. Small GNSS receivers contain small HAE databases, so the HAE value will not be exact. Some small receivers contain no HAE table at all; in this case HAE is deemed to be zero, so that the reported elevation is the uncorrected height over ellipsoid.​​​​​​​ A user of elevation data from Geometrics' MagArrow, G-864, and MagEx magnetometers may evaluate or adjust the reported values of the GGA elevation field and the GGA HAE field, by comparing the GGA HAE values to another source of local HAE data; this may particularly be useful for GNSSes that report a HAE equal to zero. Geometrics magnetometers do not currently record the values of a VDOP calculation, which offers an additional statistical estimate of the accuracy of the GNSS elevation measurement.