A New Era in Spatial Data Recording: Low-Cost GNSS

Abstract

Archaeologists have long recognized that precise three-dimensional coordinates are critical for recording objects and features across sites and landscapes. Traditionally, for relatively small areas, an optical transit or, more recently, an electronic distance measurement device (EDM) has been used to acquire these three-dimensional points. While effective, such systems have significant limitations in that they require a clear line of site. Real-time kinematic (RTK) GPS/GNSS systems (Global Positioning System/Global Navigation Satellite Systems) have been available for well over a decade, and can provide quick and accurate point measurements over a wide area without many of the limitation of older technologies. The cost of such systems, however, has generally been prohibitive for archaeologists, and so their use has been rare. Recently, a new generation of low-cost systems has become available, making this technology more accessible to a wider user base. This article describes the use, accuracy, and limitations of one such low-cost system, the Emlid Reach RS, to show why this is an important tool for archaeological fieldwork.

Archaeological Remote Sensing Using Multi-Temporal, Drone-Acquired Thermal and Near Infrared (NIR) Imagery: A Case Study at the Enfield Shaker Village, New Hampshire

“…Flights with the Solo were at recorded at 50 m altitude for a ground resolution of 4.7 cm and on the fixed wing at 90 m for a ground resolution of 8 cm. In order to accurately georeference the image sets recorded by the different sensors, Ground Control Points (GCPs) were placed across the site before every flight and recorded using either a Total Station or a Real-time Kinematic Global Navigation Satellite System (RTK GNSS) survey instrument, in this case a pair of Emlid Reach RS units [14]. For visible and multi-spectral mapping these targets consisted of printed paper targets that could be easily identified in the resulting imagery.…”

Multi-Temporal UAV Data and Object-Based Image Analysis (OBIA) for Estimation of Substrate Changes in a Post-Bleaching Scenario on a Maldivian Reef

“…2020, 12, x 7 of 26 navigation satellite system (GNSS) coordinates were recorded with Emlid Reach RS © [61], low-cost single-frequency RTK (real-time kinematic) GNSS receivers (a base station and a rover). This GNSS is able to operate in long range radio (LoRa 868/915 MHz) mode, with one receiver working as a base station that sends real-time correction to the second receiver, which acts as a rover [62]. The base station was set in a fixed position for all the surveys, and the position accuracy was calculated using the PPP correction service offered by The Canadian Geodetic Survey of Natural Resources Canada [63].…”

A Council Circle at Etzanoa? Multi-sensor Drone Survey at an Ancestral Wichita Settlement in Southeastern Kansas

“…Because of their very low thermal emissivity, most metals appear as very low values in thermal images, regardless of their temperature. Marker locations were recorded using an Emlid Reach RS system, a low-cost RTK mapping device (Hill et al 2019), and these coordinate data were then used to facilitate image alignment and georeferencing during photogrammetry post-processing.…”