PPM MarkIV project progress report

[Willy Bayot]

Hi Folks,

I am also very interested in building a magnetometer, or more speciifically a gradiometer that i can use to do some archaeological field survey work with. Like ApBerg I have a limited budget so looking for a DIY project. Have Read through most of Willy's excellenat PDF documents on the subject but can't seem to get all the information needed (like the code for the micro's) and there seem to be a few versions of it which is confusing me.

Has anyone got a working gradiometer project finished and can supply all the info (schematics, code, etc)???

Regards, Jim.

Jim,
Archaeological field surveys indeed require a gradiometer or a differential configurations in order to cancel the slow diurnal variations of magnetic field.
The field gradients generated by artificially-made underground structures like wall foundations or wells or fire pits are very tiny compared to the gradients generated from a target made of ferro-magnetic material.
It also means that the sensitivity of the instrument should be in the range of a sub-nT (sub-Gamma).
During the early prototyping phases of our PPM Markxx project, we have never got this type of sensitivity. We had to work hard for a long time on the hardware and on the signal processing to go over that.
Our current MarkIV system is indeed now able to do this type of work but its internal design is not any longer published in details.

With a limited budget, I would advise you to go to a fluxgate gradiometer for which there are a lot of DIY projects available on this forum and on others.
If you find the way to compensate well for the inherent sensitivity to temperature changes of fluxgate sensors and if you build the gradiometer with a very good mechanical precision, you could get a rather good tool with not much money invested.
Note that my Canadian partner Jim Koehler has tried to make it a long time ago and could not find a good solution to the first problem (temp. variations) but this should not discourage you from trying yourself.

Willy

[TH Jim]

@ApBerg: WOW!!! cool winding machine

I read your visitor message - I cant seem to reply in the same way, I dont know if it's a problem or if this feature has been disabled on your account ??? Thank you! I will also share with you any usefull results I get.

@Willy: Thank you for your advice. Yes, I originally wanted to use a fluxgate sensor, was looking at the FGM3, and have noted the problems with temerature sensitivity (have seen people burying them in the garden!). I don't really have time to develop a system from scratch so I will see what else i can find on the interweb!

Regards all,
Jim.

[Willy Bayot]

Geo Referencing integrated in PPM MarkIVb

Hi all,

The PPM Utility program associated with the PPM MarkIVb has been equipped with the capability to display a background map or any picture file on its GPS plot window.
Any picture file taken from a geographical or nautical MAP or even a screen dump from Google Earth can be integrated in the program using its geo-referencing functions.
This is what it looks like during a survey or during the replay of a survey. Note that this is based on a screen dump on Google Earth showing the surrounding area around the surveyed field.
This feature is now fully integrated and included in the price of the MarkIVb package.

Willy

[Willy Bayot]

WiFi connection for MarkIVb and MarkVI

Hi all,

We are now preparing and testing a WiFi link between the User Interface and the PPM control unit.
This will give the following advantages:
- For an underwater surveys system, to suppress the cable between the laptop and the PPM thus, allowing to put the laptop inside the cabin of the boat in the shade and away from water splashes.
- For an underground survey system, to allow a double operator survey with one operator comfortably sitting in his car with the PC control and the second operator walking the survey lines of the grid.

Willy

[Willy Bayot]

We have replenished our stock of MarkIVb boards with a new production series.
We are now able to assemble, test and deliver ten more MarkIVb systems.

Willy

[Willy Bayot]

Hi all,
It's now a long time that we posted any comment on this forum.
However, the normal sales and support activities related to our PPM MarkIVC are going on.
The only sizable info we could report at this point about the underwater sensor is that we have improved it one step further by using an hermaphroditic panel connector used in the professional diving industry (www.wet-connect.com). It is rated for a depth of 10000ft.
For underground surveys, the weight of the sensor is an important factor. Thus, We had switched for coil winding using aluminum wire which gives a considerable weight advantage.
However, the minus side of that is that this type of wire has a higher electrical resistance and thus, gives less polarization current for the same power voltage.
For the underwater surveys, the weight is not important (it is even better to get an heavier sensor), thus, we have switched back to the standard copper wire.

We have also very much upgraded and improved the PPM Utility program for both underwater and underground surveys in real-time operation and in post-processing.
This program can now accept the NMEA data stream from an external GPS replacing the integrated GPS.
It also can complement the GPS data from the integrated GPS with the depth data (as NMEA sentences) coming from a sonar and plot it along with the PPM data.
We have upgraded the generation of survey paths and waypoints including the automatic generation of full survey routes made of parallel survey lines based on a reference waypoint.
For the post-processing of grid-shaped survey files, we are now able to interpolate the readings and generate/display on this program 2D contoured, colored grids (exactly as Surfer does it).
These grids can then be scanned by the program to locate and mark potential targets as monopoles and dipoles with a measurement of their height and surface.

Willy

[Hubert Dong]

Development the overhausers sensor is even more difficult task than creating a proton magnetometer. If I give for you detailed description, you are unlikely it to repeat. It took us more than two years before we got a working sample. For a start, we tried to copy the finished commercial sensors.

For example, for tuning the RF resonator are necessary skills in radio engineering. To select the desired radical - PhD in chemistry. For the manufacture of glass ampules - a good glass-blowing workshop. To remove oxygen from the solution - a chemical laboratory. Going this way you will get an increase in SNR by only 10-15 dB.

In an attachment - a photo's of the sensor prototype.

Hello Konstantin,
I want to know why ?
(1)for tuning the RF resonator are necessary skills in radio engineering.
(2)To select the desired radical - PhD in chemistry.
(3)For the manufacture of glass ampules - a good glass-blowing workshop.
(4)To remove oxygen from the solution - a chemical laboratory.( *Special in this item?)
Sincerely,
Hubert Dong

[Willy Bayot]

Hi all,

We are now working on a Bluetooth connectivity between the PPM control box and its PPM Utility program running on PC under Windows.
We shall also be able to talk to an external GPS through Bluetooth.
Together, these capabilities will suppress all the cabling between the devices and the user interface.
This will allow the PPM control box to be carried in a backsack for underground surveys leaving the hand of the operator free.
It will allow the operator to stay in the cabin of the boat for underwater surveys.

With the advent of Windows 8.1 tablets (soon released with smaller 8 inch screens), the walking operator will only have to carry a light tablet during the survey sessions.
The design of the control screen of the PPM Utility program has been simplified to be operated in this mode. Larger buttons have been provided to enable the operator to work with gloves.
The fact that there will be no more cabling (USB...) going out from the tablet permits to easily insert the tablet in a waterproof envelope selected for its screen size.

Willy

[carthage]

Hi Willy;
that is a great achievement and progress on your PPM; but we are hoping that will be affordable for people with a small budget.
Thank you and good luck on your progress.
carthage

[Willy Bayot]

The tests of the Bluetooth link have been successful.
This option will not be very expensive as it was simple to implement.

Willy

[carthage]

Hi Willy;

Willy, are going to find away that the size of the sensor container will be a as small as possible as you are are making the control box compact and small?
Regards Carthage

[Willy Bayot]

UXO Detection using the PPM MarkIVb system

Our PPM MarkIVb system is now used by a professional company whose main job is to detect and remove UXO in France.
Several upgrades have been applied to our support system to facilitate this job.
UXO detection projects usually require large surface area to be systematically scanned to detect small, shallow but also large and deep explosive weapons like bombs, shells, grenades and land mines. One side effect is to eliminate as much as possible the shallow ferrous debris in order to spare a lot of useless digging.
During the passed wars, some regions have been riddled with many bombings and shellings sometimes during long periods.
As a consequence, some area contain a large number of UXO buried at various depths.

One specific type of upgrade applied on the operational PPM system was to make its carrying more comfortable during the long survey sessions.
The second type of upgrade has been applied on the post-processing system to facilitate and speed up the target detection on the survey grids.
The third upgrage was to facilitate the pinpointing on the ground of the targets detected during the post-processing.
Some of these upgrades are now operational in the field and some are still in prototyping phase.

The operation of the PPM is being optimized by the mounting of the control box, the GPS and its antenna, the battery and the sensor in a backpack leaving the hands of the operator free. The human-interface has been implemented on a 8" or 10" tablet inserted in a watertight plastic envelope and connected to the PPM control box through a Bluetooth link. The shape of the survey sessions is controlled through a precise GPS system.

The windows-based post-processing system has bee upgraded with a 2D colored grid generation process and an automatic target detection system.
The figure 95-1 attached shows the GPS and PPM tracks as they appear during the real-time session or during the review of a survey file.
You can see the numerous parallel survey lines shown by the 2D GPS plot, the field gradients displayed as variable size color bubbles and the vertical barchart showing the variations of field gradients over time. In this case, the rectangular area covered by this session is 40x40m.
Already here, some potential targets are visible. They can be located with their GPS coordinates using this window.
Then, a 2D colored contour grid is generated by a sophisticaed interpolation algorithm. This is shown in figure 95-2.
The potential targets are now much more visible. The general average field level is colored in light green and the sensible variations of field gradient are colored in warm colors for positive gradients while negative gradients spots are colored in cold colors.
From this grid, it is now possible to manually mark and list the location of potential targets and the data to be used for the evaluation of location, size and depth. From this list, it is then possible to generate a list of GPS waypoints to be used later for target pinpointing.

From this grid, it is also possible to start an automatic target detection process giving for example the figure 95-3. This process detects all the field gradients exceeding a given threshold, measuring their surface and height and marking them on the 2D grid.
Most targets generate what is called 'dipoles', i.e. a positive field peak closed to its corresponding negative peak.
Some of them reduce to 'monopoles' made of a single positive or negative peak.

Lastly, we have upgraded the real-time system to define the shortest route between the target list and to navigate the operator through that route using a virtual compass. See figure 95-4.

Willy

[Willy Bayot]

Hi all,

During the last few months, our new developments have mainly targeted the 'PPM Utility' PC-based program.
We have published a summary of its main functions in the attached document and also on our web site : http://users.skynet.be/fa352591/index.htm

Willy

[Willy Bayot]

Hi all,

We are proud to announce the release of our new MarkVII PPM system and its corresponding web site.
See www.precisemag.com

Willy

[Willy Bayot]

The main improvements of this version over the previous MarkIV version are the sun-readable color GUI display and the Bluetooth connection to the PC-based control program.
This program can run on a small 8" tablet under Win 8.1 and thus, the PPM box carried in a backsack with the operator having only the tablet in his hands.
This program has also a lot of new features, they are described in details on the new web site.

As always, the same PPM control box can be used for underground surveys AND for underwater surveys, the only difference being the sensor container.

This is two pictures of the new control box and its display during a survey session.

Willy
http://www.thunting.com/smf/magnetom...t12655.25.html