TBC COMBINED w ACCES..

194 Pages·2015·9.81 MB·English

SYSTEM DIVIDENDS

APPLICATION GUIDE
for Trimble Static/RTK GPS
w/Access 2014+ & Trimble
Business Center 2.99/3.40+

SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
ABOUT THIS GUIDE

The purpose of this training guide is to provide a practical outline and sequential framework for
discussion and exploration of the Trimble suite of GPS survey grade receivers and attendant
software products, with particular emphasis on the overall process of observing, computing, and
adjusting high accuracy survey positions. Its focus is conceptual, not cookbook, and is not meant
as a substitute or even as a complete outline of the Trimble manuals which are rich in detail and
well indexed (they need to be read), but rather as a guide for discussion and introduction to the
Static system. IN SHORT, THE PURPOSE HERE IS TO NAVIGATE THROUGH A PROJECT,
NOT TO DOCUMENT THE ENTIRE SYSTEM.
While GPS technology is expansive beyond a surveyors dreams in terms of distances covered
and precision attained, the few system restrictions are sometimes more absolute than those
surveyors normally confront. When you are in a satellite shadow, you are in the dark, there is no
GPS evening where you can take just one more observation in the fading light (even though GPS
is a 24 hour weatherproof system). In addition, the basis of the GPS observations themselves is
markedly different than conventional surveying with total stations or theodolites and EDMs, so
some change in thinking of how positions (final coordinates) are determined is necessary,
especially when relating the GPS results to established conventional monumentation.
The Trimble software is strong with considerable error trapping routines built in and the
processing robust enough to handle most data collection situations and subsequent processing.
As with all complex methodologies however, GPS observations, vector processing, and final
adjustments require sound fundamentals. The most basic components and issues of the actual
GPS "machinery" are briefly summarized in the following sections (detailed explanations can be
found in the Trimble documentation), but the operative function of this document is to begin
generating high accuracy survey positions (expressed in user specific datums and coordinate
systems) with all due speed and efficiency by focusing on the overall implementation of GPS as a
surveying tool.
With careful and prudent regard for the intricacies and components of the system however, GPS
will serve you well. The devil is in the details, so take care of the details, or they will certainly
take care of you!

NOTICE
This guide is proprietary to System Dividends. No part of this guide may be reproduced or
transmitted by any means without the express written consent
of System Dividends.

TBC COMBINED W ACCESS 3.40 - 4.DOC

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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
TABLE OF CONTENTS

BASIC WORKING/REFERENCE SURFACES .............................................................................. 8
TGO TO TBC CONVERSION ...................................................................................................... 12
TBC SETUP OPTIONS ................................................................................................................ 13
PROJECTS & DATA FLOW ........................................................................................................ 16
PLANNING ................................................................................................................................... 16
NAVIGATING THE ACCESS SCREENS ..................................................................................... 24
BASIC ACCESS STATIC SETTINGS .......................................................................................... 26
FIELD PROCEDURES & STARTUP – POST PROCESSED ...................................................... 31
GPS STATION OBSERVATION SHEETS ................................................................................... 34
GPS PROJECT OBSERVATION SCHEDULE ............................................................................ 35
CREATING A PROJECT ............................................................................................................. 37
DATA TRANSFER ....................................................................................................................... 42
POINT MANAGEMENT ............................................................................................................... 44
VIEWS .......................................................................................................................................... 53
USING CORS ............................................................................................................................... 62
USING OPUS ............................................................................................................................... 67
USING RTX POST PROCESSING .............................................................................................. 69
BASELINE PROCESSING & EVALUATION ............................................................................... 72
NETWORK ADJUSTMENTS ....................................................................................................... 79
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
CONVENTIONAL TRAVERSE ADJUSTMENT ........................................................................... 91
CREATING/EXPORTING ALIGNMENTS .................................................................................... 96
EXPORTING .............................................................................................................................. 102
GETTING STARTED W RTK ..................................................................................................... 107
RTK SURVEY SETUP CONSIDERATIONS & ACCESS CONVENTIONS ............................... 107
BASIC ACCESS RTK SETTINGS ............................................................................................. 109
BEGINNING A SURVEY ............................................................................................................ 117
DATA COLLECTION ................................................................................................................. 134
STAKEOUT ................................................................................................................................ 142
STAKEOUT RESULT FORMATS .............................................................................................. 152
MENU DETAILS ......................................................................................................................... 153
ROADS DETAILS ...................................................................................................................... 153
JOBS MENU .............................................................................................................................. 160
KEY IN MENU ............................................................................................................................ 164
SURVEY MENU ......................................................................................................................... 166
COGO MENU ............................................................................................................................. 167
INSTRUMENT MENU ................................................................................................................ 173
INDEX ........................................................................................................................................ 175
ADDENDUMS ............................................................................................................................ 177

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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
GPS SURVEY SYSTEM DEFINITION & CAPABILITIES

GPS, as originally envisioned by its developer and patron (the Department of Defense), is a
worldwide, all weather, highly accurate, and when fully deployed, 24 hour navigation system that
has evolved into a technology with vast implications beyond military navigation. Specifically for
our purposes, GPS has become a tool without peer for many of the problems facing today's
surveyors, especially in regard to large scale, high order projects. With survey grade receivers
such as the Trimble 4000/5000/R series, it is now possible to quickly perform high order control
surveys on a scale and accuracy level never before contemplated, as well as general boundary,
topo and GIS surveys on the local level. Speed and accuracy levels vary with equipment and
procedures, but individual observation times of as little as 5 seconds with closures in the range of
1:500,000+ are certainly attainable without undue expenditure of resources, as are much higher
closures with 1 hour observations. Trimble has further enhanced the basic positioning function
of GPS by developing Real Time Kinematic (+/- 1 cm.) for topography and stake out work as well
as incorporating comprehensive least squares network adjustment routines and data output
options in the available software packages.
The entire system is composed primarily of three segments; the satellites themselves (Space
Segment), the earth bound monitoring installations (Control Segment), and the users of the
system itself (User Segment). All of these combine to provide what is essentially an extremely
high order trilateration system, a technique which should be familiar to most surveyors (albeit a
system with considerably more variables than land based trilateration). Essentially what is being
measured is not the actual distance between the satellites (known positions) and the receiver(s)
(point of intersection), but rather the number of wavelengths (integers) and travel time of the
signal. From this data the "satellite to receiver" distances are computed and receiver positions
derived. From these receiver positions, the survey "network" components of azimuth, distance,
and height are computed and solved using least squares.
As with any navigation, survey, or spatial relation system such as a GIS, GPS requires some sort
of reference point from which to relate observations. In the case of GPS, the system is
referenced to ECEF coordinates which are Earth Centered, Earth Fixed (X,Y,Z) and expressed in
WGS-84. After measuring a sufficient number of signals from multiple satellites with an
appropriate receiver, the user is then able to compute positions relative to the system reference
point (a global Point of Beginning if you will). With some further computation, these positions are
processed into baselines, possibly adjusted with least squares, transformed to the ellipsoid, and
may then be related to whatever historic or legal reference system was included in the
observation network or a local user defined projection, i.e. northing/easting coordinates. It is
useful to remember that GPS baselines are essentially the inverse result of two best fit (least
square) positions, whereas conventional baselines are the result of direct observation. Both
types (GPS & conventional) may be combined and then adjusted (again in the case of GPS) as a
network with the least squares program available in TBC.
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
STATIC/FAST STATIC GPS NETWORKS
Static GPS was the original GPS application in the survey industry and allowed on a practical
level the first networks of non-intervisible points and at accuracy levels higher than conventional
procedures. By occupying different points simultaneously with GPS receivers and
observing/storing the transmitted code and carrier wave signals from at least 4 satellites,
distances from the satellites to each receiver can be computed, trilaterated positions can be
solved, and the spatial relationship of each point to another derived. In addition to the flexibility
of no line of sight requirements and the super increase in relative precision, the distance
capability of the system extends to tens of miles with medium effort and hundreds with additional
resource. To accomplish this, an occupation campaign must be carried out which includes:
simultaneous observations of at least 4 satellites; data logged at common times; and sufficient
observation time vs. distance between points, all in an environment sufficiently free of electronic
interference and offering a clear view of the satellites. While the receivers are fairly automated in
terms of field operations (assuming good survey methods regarding instrument setups and
notes), the logistics of moving personnel and equipment efficiently and profitably requires precise
planning and intention – static/fast static field operations must be a concerted effort of all
involved, that is to say all receivers must be operating together, not individually.
Once the data has been collected, the information is downloaded into a computer and comes
together in a Trimble Business Center Project for post processing. If the field conditions were
nominal the post processing is relatively automated (again assuming good survey techniques
were involved in the field work and the observation environment was appropriate) and the
software allows various levels of diagnostics and edit/repair tools to ferret out and eliminate bad
data. Once the data has been “reduced” it is formatted in positional geodetic terms of WGS
(World Geodetic System) latitude/longitude/ellipsoid height or a user defined datum such as
NAD83. From this point the data must be projected to a specified coordinate system to be useful
in the conventional northing/easting/elevation sense. Note that unlike conventional survey
measurements, GPS measures positions and computes the component parts
(azimuth/distances). This allows for some additional flexibility in network construction as the
GPS networks are not as prone to the deleterious effects of ground geometry as conventional
surveys.
REAL TIME KINEMATIC (RTK) GPS
Kinematic GPS is a general category or technique which employs carrier phase observations in
order to compute vectors and positions, similar to the above mentioned “static” GPS. However,
in contrast to the “static” method, kinematic GPS observations can be made in seconds rather
than the 8 to 20 minutes required by Fast Static or the 1 hour required by the standard Static
method. This time difference is obviously a tremendous advantage, but comes at a certain price
which is the requirement that the “Rover” unit be able to compute and continually sustain the
resolution of the integers (obtained through the measurement of the relationship between the two
(+) receivers, and their relationship to the satellites). In normal post-processed kinematic
surveying, this is accomplished by maintaining constant lock on at least 4 satellites during the
survey, including travel time between actual observations. If satellite lock is lost by the Rover
unit, the system must be reinitialized by occupying a known point (known in GPS terms) or
returning to the last point surveyed (although dual frequency receivers using Kinematic mode
may reinitialize after losing lock by observing an Unknown Point for approximately 8 minutes).
This constant “lock” requirement is sometimes difficult, and in some environments, impossible to
maintain (freeway overpasses and foliage for example). In addition, the field operator does not
have results or know whether the initialization procedure was successful until the data is post
processed in the office, long after the fieldwork is performed.
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
To overcome these shortcomings, Trimble has developed Real Time Kinematic equipment and
software that is available in several different configurations. The primary difference between the
most basic RTK and post processed kinematic is that RTK has the additional requirement of a
constant land based radio link between the “Base” and “Rover” units in order to differentially
correct for ionospheric distortion and other systematic “noise”. While somewhat restricting, this
link provides “Real Time” coordinates (both WGS84 lat/long/height and/or local values) which are
obviously required for Stake Out, and the knowledge that the survey initialization (and thus the
entire survey) is successful while it is being performed. Furthermore, Trimble offers an RTK
configuration (available with dual frequency receivers only) that allows re-initialization to be
performed either “On The Fly (OTF)” while continuing to move, or by briefly remaining stationary
in any convenient location (Known Point). It must be noted however, the “OTF” mode requires a
minimum 5 satellite configuration (re-initialization on a Known GPS point only requires 4
satellites, and is in one format or another the only method of re-initialization for single frequency
receivers).
In all cases, kinematic surveys, whether RTK or post processed, derive “Rover” positions which
are totally relative to a “Base” station. The positions of these two receivers are the ends of
“GPS vectors” (there can be as many simultaneous vectors from a single “Base” station as there
are “Rovers”). While these “side shot” vectors can be projected to whatever coordinate system is
required, they remain unverified, similar to topographic “side shots” observed with a total station.
As a result, procedures need to be developed to periodically check the survey for errors, similar
to returning to the backsight in a conventional total station survey.
As the name implies, RTK offers the operator coordinate values as they are surveyed in
real time, initially measured, formatted, and stored as WGS84 vectors from the Base
(expressed as delta x/y/z Earth Centered Earth Fixed), and then through a calibration
process transformed/projected to whatever local coordinate system is required (State
Plane, local northing/easting, etc), and importantly, also transformed to the local vertical
datum. THE CALIBRATION PROCESS IS NOT NECESSARILY DIFFICULT, BUT IT IS
ABSOLUTELY KEY TO SUCCESSFUL, ACCURATE COORDINATE PRODUCTION.
Obviously, GPS is a technology that requires many very precise and highly coordinated
components AND procedures in order to resolve sub centimeter baselines from radio signals
originating some 12,600 miles in earth orbit. There are many esoteric causes for position error
(such as radio propagation delays due to the atmosphere, clock error, etc.), but most are handled
by the receivers themselves or the software. There are however, procedures and safeguards
that can taken to insure that the data collected will be appropriate and satisfy the project. The
following is an outline of some of those components and procedures. However, the emphasis
here is on the operational procedures, rather than the hardware components themselves or the
electrical engineering inherent in the GPS system. The procedures have more user variables
and are more susceptible to error or blunders (simply put, you either have appropriate, working
receivers, or you don't - how they are used and the resultant data processed, may be another
matter). Also, a significant portion of the system (the Space/Control Segments) is largely beyond
the user's control. In fact, this guide assumes a certain leap of faith as to the notion that GPS
does indeed work, and work well if properly used. As a result, it will concentrate on those areas
that fall within the practical influence of the user, and the processes by which the user may be
able to mitigate some of the negative effects of the GPS environment.
Successful use of GPS is due to understanding not only the individual components, but
equally important, their synergy. There are many cause and effect scenarios in this
technology, it is important to recognize the effect that one phase or procedure can have
on another.
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
BASIC WORKING/REFERENCE SURFACES

ground
WGS84
Geoid (msl)
Note that the geoid/ellipsoid
relationship here is for the
continental US and is reversed in
other parts of the world.
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
GENERAL SYSTEM REQUIREMENTS & CONNECTIONS
COMPONENTS
SPACE SEGMENT
Navstar Satellites (also referred to as SVs or Space Vehicles)
When originally designed, the Space Segment was to consist of 24 satellites
providing 24 hour global navigational coverage, as well as approximately 24
hours of daily 3D survey coverage (minimum of 4 satellites). Of the 24
satellites, 21 were to be in actual use, the other 3 to serve as spares that
may be placed in service immediately. However, there are currently 32+
SVs in orbit and all are active and operational. The satellites are in an earth
orbit of roughly 12,600 miles, and carry very precise (and very expensive)
atomic cesium clocks. As any given SVs grow old, orbits decay, or other
problems arise, they will be replaced.
Glonass Satellites – In addition to the US GPS satellites, the Trimble R
Series receivers and TBC can observe and process the data from the
Russian Glonass constellation.
CONTROL SEGMENT
The maintenance and control of the entire GPS system (the SVs themselves
and the ground control stations) fall under the aegis of the Department of
Defense. The DOD maintains 5 Monitor Stations around the globe to
constantly track the satellites and upload new position information. As the
system is primarily military, first consideration is always given to military
priorities, sometimes to the detriment of civilian use (access to the system is
guaranteed by Congress, accuracy is not).
USER SEGMENT
GPS Receivers, Peripherals, and Processing Software
Survey grade receivers establish positions through the trilateration of the
distances from at least 4 satellites to each receiver. The distances
themselves are derived through an elaborate set of computations which
essentially "count" the number of whole radio wavelengths (each wavelength
is exactly 19 cm in length) which are known as the integers, plus the
fractional wavelength observed when the survey first begins. This technique
is known as observing the carrier phase and differs from navigational GPS
as well as mapping grade GPS observations (Trimble Pathfinder) in that
both of these later techniques "time" the signal's journey from the satellite to
the receiver to derive the distances (this method is known as code phase).
The practical difference between these two methodologies is significant:
carrier phase observations can be resolved to sub-centimeter levels with
RTK or post processing, whereas code phase observations typically yield
accuracies of 0.5 to 5 meters +/- with differential processing. How integers
are observed and solved is the subject of many volumes and post graduate
degrees and will not be detailed here as the principles are beyond the scope
of this guide. Suffice it to say that the parameters for this method (carrier
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA
phase) places certain restrictions on GPS observations which will be
discussed.
The minimum number of required receivers for survey precision work is 2
(operating at the same time), however, 3 or more receivers will greatly
reduce the overall time necessary to complete a project, especially in the
observation of a static network. In the RTK context, multiple rovers increase
production arithmetically.
While specific products types and versions are mentioned below, bear in
mind that this technology is rapidly changing and evolving, and care must be
taken to verify compatibility issues such as product models,
software/firmware versions, data formats, and communication parameters.
Trimble 4000 Series Survey Grade Receivers (SL, ST, SE, SSE, SSi,
4600LS, 4400, 4700, & 4800) and 5700/5800/R Series
Single Frequency - SL, ST, & SE Firmware Types and Processing
Potential (all of the following "types" require a minimum of 4 qualified
satellites, however 5 are strongly recommended to insure successful
observations!!!
Standard
Static - requires approximately 1 hour observations of 4
satellites yielding the highest GPS accuracies (up to
1:5,000,000). The 4600LS, 4700/4800 & 5700/5800/R
Series receivers use an internal clock to determine the
minimum time required for static observations, from 20
minutes with 6+ SVs to 30 minutes for 4 SVs.
Dynamic
Kinematic - requires observations as short as 5
seconds after initialization, with constant "lock" on a
minimum of 4 satellites, even when traveling between
observations. The 4600LS will only perform
Kinematic surveys using the Access Controller.
RTK (as this category of receivers is single frequency,
“On The Fly” initialization is not available) - after
initialization on a known point requiring a minimum of 4
satellites (approx. 1 minute), requires approximately 2
seconds to update a position with +/- 1 cm. accuracy.
Requires special firmware in addition to a ground radio
link.
Dual Frequency - SST, SSE, SSi, 4400, 4700/4800, & 5700/5800/R
Series Firmware Types and Processing Potential
Both Standard & Dynamic listed above as well as Fast Static.
Fast Static - approximately 8 to 20 minute observations
of a minimum of 4 to 6 satellites respectively yielding
medium accuracies of 1:1,000,000. (Can only be
processed with TBC.)
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SYSTEM DIVIDENDS, THE MOST EXPERIENCED GPS TRAINERS IN AMERICA