Sensing Archaeology in the North: The Use of Non-Destructive Geophysical and Remote Sensing Methods in Archaeology in Scandinavian and North Atlantic Territories

Abstract

In August 2018, a group of experts working with terrestrial/marine geophysics and remote sensing methods to explore archaeological sites in Denmark, Finland, Norway, Scotland and Sweden gathered together for the first time at the Workshop ‘Sensing Archaeology in The North’. The goal was to exchange experiences, discuss challenges, and consider future directions for further developing these methods and strategies for their use in archaeology. After the event, this special journal issue was arranged to publish papers that are based on the workshop presentations, but also to incorporate work that is produced by other researchers in the field. This paper closes the special issue and further aims to provide current state-of-the-art for the methods represented by the workshop. Here, we introduce the aspects that inspired the organisation of the meeting, a summary of the 12 presentations and eight paper contributions, as well as a discussion about the main outcomes of the workshop roundtables, including the production of two searchable databases (online resources and equipment). We conclude with the position that the ‘North’, together with its unique cultural heritage and thriving research community, is at the forefront of good practice in the application and development of sensing methods in archaeological research and management. However, further method development is required, so we claim the support of funding bodies to back research efforts based on testing/experimental studies to: explore unknown survey environments and identify optimal survey conditions, as well as to monitor the preservation of archaeological remains, especially those that are at risk. It is demonstrated that remote sensing and geophysics not only have an important role in the safeguarding of archaeological sites from development and within prehistorical-historical research, but the methods can be especially useful in recording and monitoring the increased impact of climate change on sites in the North.

Multireceiver SAS Imagery Based on Monostatic Conversion

“…(5) In (5), the squint angle  in frequency domain is given by ( ) P f  is the spectrum of transmitted signal. In appendix B, we further present the deducing of (3) in detail.…”

“…HE synthetic aperture sonar (SAS) [1]- [5] originates from its counterpart, synthetic aperture radar (SAR) [6]- [11]. Since SAS and SAR works in different environments, the SAS has been developing its own unique style.…”

An Improved Imaging Algorithm for Multi-Receiver SAS System with Wide-Bandwidth Signal

“…where ref r denotes the reference range. Based on (14) and Table 1, the residual quadratic coupling error is shown in Figure 10 when the system works with the narrow-bandwidth signal. Here, the reference range is the scene center.…”

“…Originating from synthetic aperture radar (SAR) [1][2][3][4][5][6][7][8][9][10], synthetic aperture sonar (SAS) [11][12][13][14][15][16] attracts investigators' interests due to its high resolution in the underwater field. Nowadays, it is widely applied to underwater mapping [14,15,17,18], target recognition [19][20][21][22], and so on.…”

“…Originating from synthetic aperture radar (SAR) [1][2][3][4][5][6][7][8][9][10], synthetic aperture sonar (SAS) [11][12][13][14][15][16] attracts investigators' interests due to its high resolution in the underwater field. Nowadays, it is widely applied to underwater mapping [14,15,17,18], target recognition [19][20][21][22], and so on. Considering the traditional monostatic SAS system, the maximum imaged swath is determined by the pulse repetition frequency (PRF), and the low PRF allows for a wide swath.…”