Home' Position : Position Dec Jan 2016 Contents Chris Rizos is one of Australia's
foremost academic figures in any
field, having most notably stood as
president of the International Association
of Geodesy from 2011-2015, in addition to
holding many other prestigious positions
too numerous to mention. Prof. Rizos
has been a member of the academic staff
at UNSW since 1987, where he is now
professor of Geodesy and Navigation.
It was in the early 1990s that he started
the Satellite Navigation and Positioning
(SNAP) group at UNSW. In 2014 it was
relaunched, and now brings together
staff from both UNSW's School of Civil
and Environmental Engineering and the
Australian Centre for Space Engineering
Research, within the School of Electrical
Engineering and Telecommunications.
SNAP has long been considered
Australia's premier academic GPS and
wireless navigation technology research
group. Prof. Rizos himself was co-author
of the first book published on GPS
surveying and the author/co-author of
over 600 journal and conference papers.
He is instrumental in advancing
innovative positioning technologies in
his role as professor at UNSW, where this
year the Mobile Mapping Symposium
2015 will be held over 9-11 December and
the IGS Workshop on 8-12 February 2016.
Prof. Rizos shared with Position magazine
his take on the past, present and future of
positioning and navigation.
You've been academically
involved in positioning in all
its forms since the 1980s,
having seen the progression
from the TRANSIT satellite
system through to GPS and
now to multi-constellation
GNSS. Where do you see
positioning going next?
It wasn't until the early 1980s, when I
had a postdoctoral position in Germany
did I hear about GPS. When I came back
to UNSW in 1984 as a research fellow,
we started looking at the use of GPS for
geodetic surveying to replace the survey
techniques 'from hilltop to hilltop'. The
first GPS geodesy survey was undertaken
in 1985 in South Australia. At that time
we hadn't even seen a GPS receiver as
they were too expensive, and hence our
research was on measurement modelling,
software for data processing, and
educating surveyors and others on the
potential of GPS as a positioning tool.
Remember that 1985 was ten years
before GPS was declared fully operational.
That meant surveying/geodesy academics
were studying GPS precise positioning
before any other type of engineer or
scientist. This early lead in GPS is still
reflected in the very strong influence that
surveying/geodesy has in the GPS/GNSS
world. Surveying/geomatics departments
all over the world are still producing the
majority of well-rounded PhD graduates,
who are continuing to drive precise
positioning and navigation research, and
The early work of SNAP focused
on GPS and on precise positioning
technologies, algorithms and applications.
During the 1990s GPS became
increasingly seen as a precise navigation
technology (not just for surveying), as
well as a tool for private surveyors (not
just geodetic surveyors). Hence there
was interest in RTK, in rapid ambiguity
resolution, in developing techniques and
guidelines for GPS-based positioning.
By the start of the 2000s, SNAP was also
well and truly researching non-GNSS
navigation technologies, such as inertial
systems and ranging systems such as
Locata. Multi-GNSS is now the norm,
as we work increasingly with as many
transmitted signals as we can (which
brings with it its own research challenges).
From this you may be able to discern a
few trends, such as:
• GPS to multi-constellation GNSS.
• GNSS for niche applications expanding
to mass-market apps.
• Reduction in the cost and applications
of precise positioning.
• GNSS for vehicles, indoors and IoT (in
combination with other navigation/
• GNSS driving all modern geodesy
scientific and operational (datum,
• The need to go beyond GNSS to
other technologies because of GNSS
vulnerabilities and shortcomings.
What research are you
and the team at UNSW
undertaking in these areas?
Geodesy-related: datum studies (including
how to promote dynamic datums to the
geospatial community), modernised height
systems, ground deformation (InSAR,
GNSS and other techniques) for 'patching'
the datum realisation, 4D positioning,
atmospheric remote sensing.
Precise GNSS positioning: Precise
Point Positioning (PPP), multi-GNSS
biases, role of CORS in multi-GNSS
world, quality control, Satellite-Based
Augmentation System (SBAS).
Multi-sensor systems: GNSS+
GNSS+vision systems), use in UAV and
other moving platforms.
Precise positioning applications:
Intelligent Transport Systems (ITS),
including cooperative positioning,
driverless vehicle operations.
Indoor positioning: Locata-based
precise positioning & timing, Wi-
Fi-based positioning, positioning in
What do you think are some
of the stand-out applications
of indoor positioning that
will see it garner widespread
adoption and what are
the key technologies
required of such systems?
Always we start with emergency
than the mass market location-based
services (LBS) type applications. The
latter will be solved by the smartphone
Professor, Geodesy and Navigation at
University of New South Wales (UNSW).
Past President, International Association of
Geodesy (IAG), 2011-2015.
Member of the Bureau, International Union of
Geodesy & Geophysics (IUGG).
Member, Governing Board & Executive of the
International GNSS Service (IGS).
Chairman, Multi-GNSS Asia Steering Committee.
President, Australian Institute of Navigation.
Q&A with Professor
14 position December/January 2016
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