GNSS + sensors have transformed surveying

Photo: payamona / iStock / Getty Images Plus / Getty Images

Matteo Luccio

In this issue’s cover, a man with a backpack lidar unit, a GNSS receiver and a tablet computer is surveying in a complex and challenging urban setting. That same lidar unit also can be mounted on a UAV. One of the contributors to this month’s cover story describes the role of aerial photogrammetry in the architecture, engineering and construction (AEC) industry. Satellite navigation, remote sensing, mapping software, a great variety of platforms, and ever more powerful handheld computers — those are the key ingredients in today’s ecosystem of geospatial technologies. The current generation of surveying equipment has more than halved fieldwork in the past two decades while greatly improving the quality of the data collected.

The AEC industry relies on surveyors to be “a bridge between the existing landscape and the design landscape,” said another contributor to our cover story. Unlike traditional boundary surveying, he explained, surveying for AEC requires consideration of a detailed 3D world. It also involves many more stakeholders and much greater liability.

The tight integration of GNSS, inertial systems, lidar sensors and 360° spherical imagery into mobile mapping systems makes 3D modeling possible and traditional GNSS or optical measurement instruments obsolete. However, while inertial systems are invaluable to bridge brief gaps in the availability and reliability of GNSS signals, they are far from the panacea they are sometimes claimed to be, as Brad Parkinson reminds us in an interview with Dana Goward, also in this issue.

Surveying for AEC requires at least centimeter accuracy. The challenges of surveying in urban settings include urban canyons that occult signals and create multipath, traffic and multiple layers of underground, ground-level and above-ground infrastructure.

Beyond the construction phase, 3D survey data is increasingly used to create digital twins of buildings, which facilitate their operation and maintenance throughout their life cycle and help lower their carbon footprint. Once they have completed an initial survey, surveyors often set control to be used for machine control — the theme of our cover story in next month’s issue.

In this issue we also:

• Inaugurate a “letters to the editor” section to make more room for debate in the GNSS/PNT community on the critical issues it faces.

• Report on a Jet Propulsion Laboratory study of the impact on the ionosphere of the enormous volcanic eruption in Tonga and the beginnings of a GNSS-based early warning system for natural hazards.

• Continue our series of articles on GNSS constellations, with an update from Japan’s QZSS constellation.

• Feature three studies: one on real-time simulator testing using an NMEA data stream, one on the first transmission of L1C/B signals by QZSS, and one on self-driving cars in major metropolitan areas.

All these advances, however, are threatened when GPS is threatened. Earlier in the month, three members of our editorial advisory board comment on the recent threat to GPS satellites by the Russian government.

Matteo Luccio | Editor-in-Chief
mluccio@northcoastmedia.net