SaLIS Vol. 65, No. 2
June 2005
Book Reviews
GPS Satellite Surveying, 3rd ed. by
Alfred Leick, Wiley and Sons, Inc.
Hardcover, 9.6 x 6.3 x 1.0 in.,
ISBN0471059307, $125.00
This latest
edition of Professor Leick’s estimable text, GPS
Satellite Surveying, 3rd ed., is a significant reworking of the previous
edition and includes a good deal of new material. Among the more significant
additions are a detailed explanation of the workings of the LAMBDA method of
integer estimation and his discussion of planned modifications to U.S. GPS
satellites. Unlike many other updated texts, this volume is actually shorter
than previous editions.
The text is
unique because of its emphasis on two primary areas: GPS and the method of
least squares. While centered on these
themes, the author provides sufficiently detailed treatment of closely related
issues to assist understanding of the main thrust of the text. These closely
related topics include the 3D geodetic model and 2D conformal mapping, as well
as discussion of basic geodetic quantities. Surveyors seeking to combine
conventional terrestrial observations with GPS will benefit from his clear and
concise discussion of the 3D geodetic model.
The
organization of the text develops from the basics of reference frames and datums to satellite systems (including GLONASS and
Galileo), the method of least squares and related statistics, GPS observables
and the modeling of error sources, and network adjustments, and concludes with
a discussion of ellipsoidal and conformal mapping. The author has wisely moved
some lengthy derivations and background mathematical tutorials to
appendices.
As can be
seen from the list of topics, the book covers an impressive range of material.
Overall, the text provides comprehensive information in a clear, concise, and
rigorous manner. The notation is consistent and conforms to surveying and
geodesy conventions. Subject treatments are supplemented with well conceived
figures. Numerous tables are provided. The tables greatly contribute to the
book’s value as a reference.
The
usefulness of the text is enhanced by an excellent list of references as well
as a number of links to various agency/organization web sites. The author’s web
page (http://www.spatial.maine.edu/~leick/gpshome.htm) includes a link to
errata in the current edition.
This text
is more than a “Dummy’s Guide to GPS.”
It explains how the GPS works and how it is linked via the method of
least squares to the determination of coordinates. While more detailed than the
“practical minded” might appreciate, those with an interest in the “why” and
“how” will find this text to be a worthwhile purchase.
The
presentation on GPS is complete and well done. It includes good expositions as
well as a compilation of useful formulas.While most
surveyors will not have a need to compute many of the corrections applied
during GPS data reduction, the detail provided in the text is sufficient to
develop an appreciation of their magnitudes.
Readers
with adequate mathematical preparation can use the text as a self-teaching
tool; this notwithstanding, the level of presentation is high, such that those
without adequate preparation may find it intimidating. However, those willing
to put forth the effort to read the text will find that in many cases, the
explanations are sufficient to convey the important points. The book is also an
excellent reference as it provides a comprehensive set of definitions and
equations.
The third
edition of Leick’s GPS Satellite Surveying does an
admirable job describing new developments relevant to GPS as a system and its
uses. Among them are new codes and signals intended as part of GPS modernization.
Those interested in how networked real-time kinematic
(RTK) systems work will find a clear explanation.
Leick
details efforts by various entities to provide positioning services. He
describes, in good detail, the Precise Point Positioning Service (PPP) provided
by the Jet Propulsion Laboratory. The PPP service provides a centimeter-level
accuracy position for single static receivers using long observation sessions.
The author also mentions the development of the relative positioning service—NOAA/NGS’
online positioning user service (OPUS)—in the U.S. although he does not mention
the comparable Australian and Canadians systems.
While I
found the text to be excellent, I had a few quibbles. My first complaint is
about the index. A work intended for use as a reference should have a more
detailed index. Second, in his presentation on the geoid,
Leick only discusses the gravimetric geoid. This ignores the important role of hybrid geoid models that support direct conversion between
ellipsoid and orthometric heights. Hybrid geoid models have been developed in the U.S. (since 1996)
and elsewhere. These models combine the gravimetric geoid
with GPS ellipsoid heights on leveled bench marks. The current U.S. hybrid geoid model, GEOID 03, was developed from the USGG2003
gravimetric geoid.
In closing,
I strongly recommend consideration of the text by persons interested in either
GPS or least squares. The reorganization and new material make it a significant
improvement over the earlier edition.
The text can be used to teach least squares and GPS to students with
sufficient mathematical preparation.
The book is an excellent source of information on modeling used in GPS,
as well as many of the transformations used in surveying.
Donald M. Mulcare
Geodesist–State Advisor
NOAA, National Geodetic Survey
Texas A&M University–Corpus
Christi
Dept. of Computing and Mathematical
Sciences
6300 Ocean Dr., ST 210, Unit 5797
Corpus Christi, TX 78412-57
donald.mulcare@noaa.gov