GROUND PENETRATING RADAR AND THE SURVEYOR€¦ · Ground-penetrating radar (GPR) is a geophysical method that is often mentioned in news commentaries for its use in locating unmarked

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GROUND PENETRATING RADAR

AND THE SURVEYORw/ Case Studies

Joseph D. Fenicle, PS

Ohio & Michigan Professional Surveyor

Office of the Fulton County EngineerWauseon, Ohio

Angular By Nature, LLCAdrian, MI

POB - Point of Beginning – April 2009 Article


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GPR

Michael Friedhoff, Project Geologist

Mannik Smith Group, Inc.

Canton, MI

John Kessinger, Regional Director

Ground Penetrating Radar Systems, Inc.

Sylvania, OH

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What is GPR?

“GPR works by sending a tiny pulse of energy into a material and

recording the strength and the time required for the return of any

reflected signal. A series of pulses over a single area make up

what is called a scan. Reflections are produced whenever the

energy pulse enters into a material with different electrical

conduction properties or dielectric permittivity from the material it

left.”

http://www.geophysical.com/whatisgpr.htm

What GPR is not!

►Radiography (X-Ray Technology)

►Metal Detector

►Gradiometer

►Acoustic Technology

►New Technology (i.e. Spar Utility Locator)

What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

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What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

What GPR is not!


Radiography uses a very small dose of ionizing radiation to produce pictures of the body’s internal structures.

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What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

What GPR is not!

►Metal Detector

Metal Detectors detect the

presence of metal nearby.

What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

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What GPR is not!

►Gradiometer

A gradiometer is an instrument for

measuring the gradient of an

energy field, especially the

horizontal gradient of the earth’s

gravitational magnetic field.

What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

What GPR is not!


Acoustic Technology is the

science of using sound to

determine the distance and

direction of its source.

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What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

What GPR is not!


According to Optical

Ranging “…the

technology is based on

the optimization of data

from many sensors

against a physical

model of the magnetic

field expected from a

utility line.”

What GPR is not!


►Metal Detector

►Gradiometer



►Curb Box Charger

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What GPR is not!

►Curb Box Charger

The Curb Box Charger

simply puts a magnetic

charge on ferrous metal

objects.

How Does GPR Work?

►Antenna

►Control Unit

►Power Supply

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How Does GPR Work?

►Antenna

“The antenna receives the electrical pulse produced by the control

unit, amplifies it and transmits it into the ground or other medium at

a particular frequency. Antenna frequency is one major factor in

depth penetration. The higher the frequency of the antenna, the

shallower into the ground it will penetrate. A higher frequency

antenna will also ‘see’ smaller targets. Antenna choice is one of

the most important factors in survey design”


How Does GPR Work?

►Control Unit

“The control unit contains the electronics which triggers the pulse

of radar energy that the antenna sends into the ground. It also has

a built-in computer and hard disk/solid state memory to store data

for examination after fieldwork.”


How Does GPR Work?

►Power Supply

“…GPR equipment can be run with a variety of power supplies

ranging from small rechargeable batteries to vehicle batteries and

normal 110/220-volt. Connectors and adapters are available for

each power source type.”


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How Does GPR Work?

“GPR operates much like a sophisticated and superexpensive fish finder”.

POB – April 2009

How Does GPR Work?

How Deep Does GPR Work?

http://www.usradar.com/how-it-works.shtml

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Ground-penetrating radar (GPR) is a geophysical method that is often mentioned in news commentaries for its use in locating unmarked graves, clandestine burials and tunnels, terrorism and military hazards, and disaster victims. However, the effectiveness of GPR in these activities is highly site-specific and soil dependent. A common concern of GPR service providers is whether or not GPR will be able to achieve the desired depth of penetration in the soils of an assignment area. In many soils, high rates of signal attenuation severely restrict penetration depths and limit the suitability of GPR for a large number of applications. Knowledge of the probable penetration depth and relative suitability of soils can help service providers assess the appropriateness of using GPR and the likelihood of achieving acceptable results. Soil attribute data contained in the State Soil Geographic (STATSGO) and the Soil Survey Geographic (SSURGO) databases have been used to develop thematic maps showing, at different scales and levelsof resolution, the relative suitability of soils for many GPR applications.

http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053622

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Why Use GPR?

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Why Use GPR?

Why Use GPR(for surveying)?

WHAT LIES BENEATH

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“When a corner is positioned in accordance with the lost corner theory of proportioning, the surveyor must be convinced that no future surveyor or court will be able to locate the original corner in a different place. Proportionate measurement is always a rule of last resort.”

Walt Robillard, et al. Brown’s Boundary Control & Legal Principles

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B. Description of corner evidence found and/or method applied in restoring or re-establishing corner.

October 11, I traversed to tie together existing monumentation in 4 cardinal directions from this

corner from A-12, T5S, R6E to M-3, T6S, R5E on the Range Line, as well as L-13, T5S, R5W and

B-1, T6S, R6E. The Baldwin survey notes 3 plow points and 2 stones between A-1 and A-3.

Warnke recovered the 3 plow points in 1994. Using the angles and chainage of the Baldwin

survey with the recovered points, I proportioned several positions to look for the stone at this

corner, as well as the stone ¼ mile south. With Glenn Richard’s help, we drilled thru the

pavement in approximately 30 locations to a depth of 18” and probed to about 40”. We also

checked on the occupied line ¼ mile south of this corner in the middle of the pavement. We also

checked around the Marino corner. We did not find any evidence worthy of proceeding to

excavate thru the asphalt. Using the data I obtained, as well as traverse work done by Richard

and Warnke in Section 6, T6S, R6E, and monumentation found by Warnke from the 1890 Baldwin

survey, it is clear there are inconsistencies between the Baldwin survey, the road survey, and

measured distances between found monumentation and this corner is considered lost. The

position determined by double proportionate measurement would best fit the pipe as set by Glenn

Richard in 1974. December 1, 2011 at 2” depth, found a 1” O.D. iron pipe, being 18 ½” in length.

Found no further evidence. I accept the position of the iron pipe as set by Richard in 1974 as the

best available evidence of the position of the original corner. Set a 5/8” by 36” rebar in place of

the pipe in a set monument box.

Courtesy of:

Consumers Energy, Jackson, MI - Phil Norder, PS

GPR Case Studies

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Thank You - Questions

Documents

GROUND PENETRATING RADAR AND THE SURVEYOR€¦ · Ground-penetrating radar (GPR) is a geophysical method that is often mentioned in news commentaries for its use in locating unmarked