Atec G-858 User Manual

Portable Cesium Vapor

A Professional Magnetic Mapping System

For Utilities, Ordnance, Archaeology, Environmental, Minerals and Petroleum Surveys

Magnetometer

Model G−858 MagMapperTM

 Excellent Performance

Low Noise/High Sensitivity, best in
the industry – 0.008nT/Hz RMS –

and world wide operation

 Very Fast – Log mag and GPS at

up to 10 samples per second for
economic large area surveys at high
sample density

 Optional Non-Magnetic cart

for near surface target search

 Optional Integrated GPS

with Backpack – Includes non-

magnetic backpack and NovatelTM
WAAS/EGNOS/MSAS ready GPS

 Low AC Field Interference –

Best in the industry for rejecting AC
power line grid noise (50/60 Hz)

 Easy-to-use – Simple setup and

rapid in-field map generation with
free MagMap2000™ software

 Reliability – Our Cesium sensors

never need calibration or factory
realignment. Designed for extreme
ruggedness and reliability.

 Designed for large surveys in

many disciplines – This

versatile tool is specially designed
for large area surveys with 8 hr data
storage capacity and two 6 hr
battery packs.

OPERATION

Stanford Metal Test Site and
Archaeological Survey Maps

The map on the left is data taken at a magnetometer test
site on Stanford University campus. Metallic objects of
different material, size, shape and weight were buried
throughout the 100 m x 100 m survey area at different
depths. Magnetic features were chosen to simulate
common environmental, engineering and UXO targets to be
able to characterize anomaly shapes and magnitudes.

This survey was conducted using a single sensor G-858
cesium magnetometer held on an aluminum staff at waist
height. Measurements were taken at 10 Hz at a normal
walking pace with lines separated by 2 m.

Photo credit to Geometrics, Inc with special thanks to

Stanford University for access to test site.

.

The map above is of a large Roman-era farm site in the English East Midlands, defined by ditch and pit fills and spreads of
magnetic soil and situated on fine grade till deposits over mudstone.

Plotted black -3.5 nT, white +3.5 nT from data collected using three G-858 magnetometers as dual magnetometers, with sensors

0.3m above the surface on a ATV-pulled sledge and coupled to ArchaeoPhysica's multi-instrument acquisition system exploiting
the real time RS232 data transfer from each magnetometer. Although the data is clear, subsequent excavation by archaeologists
revealed only the bases of features which highlighted the potential of magnetic survey for mapping otherwise poorly preserved
sites below arable fields.

Data courtesy of ArchaeoPhysica, with special thanks to Martin Roseveare for providing this image and information.

The G−858 MagMapper uses
a graphical interface to make
survey design and data
acquisition quick and
efficient. A "Simple" or

“Mapped” Mode uses line

numbers and known staked
reference points to define the
map parameters. Or the user
may use the integrated
Novatel Smart-V1™ GPS for
mapping positions
automatically. Position
information may come from
an external GPS, from
regularly spaced fiducial
marks input by the operator or
both. At any time, the user

may switch to “profile” mode

to observe the last 5 data lines
as stacked profiles.

Data is collected in up to 5
separate survey files and
transferred via high speed
RS−232 data link (or USB
with converter) to a computer
for further analysis and map
generation. The full featured
graphical data editing
program MagMap2000 is
provided to allow
repositioning, realignment, GPS
smoothing, data filtering and
interpolation of the data. After
editing, the data is formatted in
either Surfer for Windows or
Geosoft formats for further plotting
and analysis.

SPEED AND
EFFICIENCY

G−858 data acquisition offers
either continuous (automatic) or
discrete station recording. Data
quality is uniformly high and lower
costs are inherent for most projects
due to the high sampling rate of the
instrument in continuous mode.
This allows the operator to survey
an area at a fast pace, covering as
much as 10 times more area in a
given time period than other
magnetometers.

RELIABLE, RUGGED
& LOW COST DESIGN

In addition to its speed and
sensitivity, the G-858 is also
reliable, economical, and easy to
use. Electrical connectors on the
G-858’s sensor have been
eliminated in order to increase
reliability and reduce setup time.
The G-858’s internal firmware has
been streamlined to include those
features important for UXO,
archaeological, environmental,
utility, and mineral exploration. As
for economy - Contact Geometrics
for a quotation today! You’ll be
pleasantly surprised.

APPLICATIONS

The concentration of magnetic
minerals often varies with
geological formation or chemical
alteration and can indicate
hydrocarbon bearing structures
or economic mineral deposits. A
primary application of the G−858
MagMapper is surveying for

utility lines, UXO’s,

archaeological, environmental,
and mineral projects. The G-858
is an excellent instrument for use
in academic research and
education and can also be used
for local environmental studies
such as mapping waste sites,
locating buried metal drums and
storage tanks buried pipelines,
well-heads and other sizable
ferrous structures.

DIGITAL QUALITY

G-858 and GPS Re-Usable Shipping
Case with foam padding and transport
wheels

The G−858 system produces raw
data of the highest quality. Data is
digitally recorded in compressed
form in high capacity RAM and
later transferred to a computer for
permanent storage and processing.
Sensitivity, resolution and
recording rate of the cesium
magnetometer are user selectable
as well as mapped survey grid
coordinates or GPS position data.

The system is ruggedly packaged
for extreme field conditions. Data

storage is sufficient to record 8
hours of data at the maximum rate
of 10 Hz. Battery life is
approximately 8 hours powering
both the Magnetometer and
Novatel Smart-V1™ GPS.

MagPick software with multiple data
processing windows

 other client supplied contouring

programs.

 Conversion of GPS to UTM

coordinate system using a
selected Datum.

In addition to the standard
MagMap2000 download and
editing software, Geometrics is

pleased to offer MagPick™, a full

sensor orientation program for
performing surveys worldwide in
any survey direction.
MagMap2000, MagPick™ and
CSAZ™ are available on our
website for free download.
Manuals for these programs are
supplied as internal documents in
PDF format.

NOVATEL
SMART-V1™

Accurate data positions are as
important as accurate magnetic
field measurements and
Geometrics is pleased to include
the Novatel Smart-V1™ as an
integral part of the G-858 system.
This small light-weight, all-in­one GPS Antenna and electronics
package is
WAAS/EGNOS/MSAS ready
for <1.5m positioning.

MagMap2000 GPS Track Plot

BASIC SOFTWARE

A basic software package
MagMap2000 is supplied as an
integral part of the G−858 system
and provides:
 Transfer of the raw

magnetometer, base station and
other survey data to the client
PC

 Standard corrections for

position errors, transients, and
time varying errors (diurnal)

 GPS track plot with adjustable

smoothing and independent
point editing

 Repositioning, linear

interpolation and format of
corrected data into X, Y, Z or
Latitude/Longitude ASCII
columnar values for use with
Surfer for Windows, Geosoft or

Novatel GPS Antenna/receiver

The Smart-V1™ systems is
installed on Geometrics non­magnetic back pack and carefully
screened and degaussed for
minimum magnetic interference.

The Smart-V1™ is designed to

featured potential field analysis
package with excellent profile and
contour map generation capability.

MagPick™ can perform source

body inversion, reduction to the
pole, upward continuation and a
variety of other transforms and
gradient extractions. We are also
pleased to offer a Windows™
version of CSAZ™, a world total
field map, field inclination and

be quickly assembled and
installed on the backpack, with
special mounting studs and a
cable wiring harness for data and
power distribution. The storage
case allows the main components
to be stored as a unit providing
minimum assembly at the job
site. The storage case is a rugged
reusable fiberglass and aluminum
travel case with handles and
wheels for easy transport.

G−858 MagMapper™ SPECIFICATIONS

MAGNETOMETER / ELECTRONICS

Operating Principle: Self-oscillating split-beam Cesium Vapor (non-

radioactive Cs

133

) with automatic hemisphere switching.

Operating Range: 20,000 nT to 100,000 nT
Operating Zones: For highest signal-to-noise ratio, the sensor long axis

should be oriented at 45, 30to the earth’s field but operation will continue
through 45, 35. Sensor is automatic hemisphere switching.

Sensitivity Statistics: 90% of all reading will fall within the following Peak­to-Peak envelopes:

0.03 nT at 0.2 sec cycle rate

0.02 nT at 0.5 sec cycle rate

0.01 nT at 1.0 sec cycle rate

Noise: < 0.008 nT/Hz-RMS
Heading Error: < 1.5 nT including backpack and GPS
Gradient Tolerance: > 500 nT /inch (>20,000 nT/ meter)
Temperature Drift: < 0.05 nT per C
Cycle Rate: Variable from 0.1 sec to 1 hr in 0.1 sec steps or by external

trigger.
Data Storage: Non-volatile RAM with capacity for 8 to 12 hrs of

magnetometer, time, event marks, field notes and XYZ or GPS locations.

Audio Output:

1. Audio tone of field variation; pitch and volume adjustable. (Search
mode)

2. Audio pulse each 1 second (Pace metronome).

3. Alarm for loss of signal, low battery or quality control setting exceeded.

Data Output: Three wire RS-232 standard serial port, optional continuous
real time transmittal of data via RS-232 to PC. Total memory output transfer
time less than 5 min. at 115,200 baud.

Visual Output: 320 x 200 graphic liquid-crystal display, daylight visible
with selectable outputs for:

1. Data display: Up to 5 stacked profiles, real time or review mode. Survey
grid showing boundaries and position.

2. All system set-up functions, e.g., memory status, data transfer, sample
time.

3. All Survey set-up functions, e.g., survey profile number and direction,
station number or GPS data transfer protocol, line number.

4. Survey monitoring functions, e.g. total field, noise level, profile number
x or x-y coordinates.

Internal Clock: Resolution of 0.1 sec, drift: < 1 sec/day
Battery Life:

1. 24 VDC rechargeable gel cell, 6 hrs for Mag w GPS. Magnetic

effect less than 1.5 nT (γ) at 4 ft

2. Internal backup battery for clock and non-volatile RAM.

Software: Supplied as part of the basic system and including functions for:
Operating Software:

1. Survey Modes:
a. Search survey
b. Simple survey
c. Map survey, station or continuous
d. Base station

2. Data acquisition/display:
a. Acquire and store data and survey functions.
b. Display profiles, total field to 0.1 nT resolution, survey / map

parameters and diagnostics.

Post-acquisition Software: MagMap2000 software for installation on
customer’s computer.

1. Data transfer and corrections:
a. Transfer of data from the field Magnetometer

GPS, or Base station to PC.
b. Diurnal correction using base station data.
c. Processing the corrected data into ASCII values of X-Y-Z.

2. Data Processing functions include spike editing, spline filtering,
repositioning of X, Y, Z or GPS Lat/Long, conversion to UTM
coordinates, profile and contour map plotting..

MECHANICAL

Sensor: 2-3/8” dia., 6-3/4” long, 12 oz. (6cm x 15 cm, 340 grams)
Backpack: Backpack for Magnetometer, 9.5 lb (4.3 kg). Includes Nylon

chest harness with all cables attached (1 kg to 1.3 kg)
Battery: 3” H, 5” W, 8” L, 3.5 lbs (8 cm x 13 cm x 20 cm, 1.6 kg) belt-

mounted, attaches to harness.

Console: 6” W, 3” H, 11?”L, 3.5 lbs. (15 cm x 8 cm x 28cm, 1.6 kg), attaches

to battery belt and harness. Magnetic effect less than 1 nT at 4 ft

ENVIRONMENTAL

Operating Temperature: -25C to +50C (-13F to + 122F)
Storage Temperature: -35C to + 60C (-30F to + 140F)
Water Tight: Weatherproof in driving rain
Shock: Survive a 3 ft drop onto a hard surface

WARRANTY: 1 YEAR on G-858 and sensor, one year on accessories

Novatel Smart V1™ Specs:

• Code and carrier phase tacking with 1Hz (optional 20 Hz) Position,
velocity, time output or optional 20 Hz raw data output

• SBAS capable and designed for harsh environments

• RS-232, RS-422 compatible interface

Hardware Specs:
Size and Weight 115mm dia x 90mm height, Weight: 575 g
Input Voltage: +9 to +28 VDC
Power Consumption: 1.8W (typical)
Com Ports: 1 RS-232 (optional 2 RS-232) at up to 19,200

baud

Operating Temperature: -40°C to +75° C

GPS L1 Product Performance

Position Accuracy: Single point L1 <5 m CEP
WAAS L1 <1.5m CEP
Measurement Precision: L1 C/A Code 18 cm RMS
L1 Carrier Phase 1.5 mm RMS
Data Rates: Measurements 1 Hz (optional 20 Hz)
Position 1 Hz (optional 20 Hz)
Time to First Fix: Cold Start 60 s
Warm Start 45 s
Hot Start 35 s
Signal Reacquisition: 0.5 s typical

GEOMETRICS INC. 2190 Fortune Drive, San Jose, California 95131, USA V1.3 06-20-2012
Tel: [phone] – Fax: [phone] – Email: [e-mail]

GEOMETRICS EUROPE 20 Eden Way, Pages Industrial Park, Leighton Buzzard LU7 4TZ, UK
Tel: [phone] – Fax: [phone] – Email: [e-mail]

GEOMETRICS CHINA Laurel Technologies, Ste 1807-1810, Kun Tai Int’l Mansion, #12B, Chaowai St., Beijing 100020, China

Tel: [phone] – Fax: [phone] – Email: [e-mail]