Curiosity really is a marvellous thing. It drives us to explore the unknown – be it space, the depths of the sea or ancient civilisations. Ancient civilizations are particularly interesting as they paint a picture of life before modern technology. Whilst some insight can be garnered into life before technology from uncontacted tribes, this is only a small part of the picture and does not provide the Indiana Jones like thrill of the chase or an answer to the existential questions: who are we? Where do we come from? Whether the interest is motivated by prestige, financial reward or an insight into what life used to be like, people have been exploring history for a very long time.
Historically, determining a site for investigation required artefacts visible on the surface, or a historian surveying lands in person and using invasive techniques in relatively large areas to identify artefacts. The invention of the now well-known metal detector simplified artefact discovery a great deal. The metal detector is described in US3662255A, with the application dating back to 1970, which claims:
“a circular inductor assembly for a metal detector including: a coaxial cable having an inner control conductor, an outer conductor coaxial with and about said inner conductor, insulation means between said inner and outer conductors and about said outer conductor, said cable being disposed in a circular coil having a plurality of turns; a conductive shield disposed about the bottom portion of said coil; casing means about and enclosing said coil and said shield; and means for connecting one end of said inner conductor, said outer conductor and said shield to an electric ground and for connecting the other end of said inner conductor to an electric circuit.”
As is apparent from the claim, the metal detector only identifies metal as an inherent limitation of its inductive nature, but this gives a starting point to find other interesting artefacts. Thus the tool allows an archaeologist, or anyone else with the tool, to find a precise and interesting starting point for exploration, as long as the ancient civilisation had discovered metal.
Near surface magnetometry has also been known for a long time, as is demonstrated by US3126510A, which uses distortions of the earth’s magnetic field to determine what lies beneath. More recent advancements of the technology have increased resolution of the data obtained as described in US10156134B2.
However, a metal detectors and magnetometry may be of little use in investigating some sites. For example, stone formations are arguably a more interesting aspect of Stonehenge and are unlikely to show up well using either system. Given the magnitude and the fragility associated with Stone Henge, it is not practical to consider excavating large parts of the site without additional information both due to the expense and risk of damaging subsurface structures. Such information only began to become available with several more recent advancements in technology, such as the introduction of ground penetrating radar and laser scanners.
Early embodiments of ground penetrating radar date back to 1972 and are described in, for example, US3806795A. The system is capable of generating a profile chart indicating the magnitudes of the reflected signals and the depths at which the reflections occurred. More modern systems utilise an ultra-wide band signal to obtain more information, such as the system described in US5673050A. This ultra-wide band ground penetrating radar system can provide an almost futuristic three-dimensional mapping of underground objects and voids with non-invasive detection.
Although all of the aforementioned technologies have had a notable effect on archaeological investigations, perhaps the most exciting recent technological development for exploring a given site is light imaging, detection, and ranging technology, otherwise known as LIDAR. LIDAR illuminates a target with pulsed laser light and measures the distance travelled to the target by measuring the reflected pulses with a sensor. The return time and the degree of scattering of each of the laser pulses differs based on the wavelength of the pulse. This information can be used to make digital 3D representations of the target.
Many discoveries have been attributed to LIDAR, such as the most detailed map ever produced of the earth beneath Stonehenge, more than 60,000 hidden Maya ruins in Guatemala, and vast medieval cities in Cambodia.
LIDAR technology has far reaching benefits and unsurprisingly has been the subject of many patent applications, such as US20090273770A1, which relates to a method of controlling the output of a LIDAR system to make it safe for people on the ground. This particular system takes into account a human tissue safety model to avoid exposing people on the ground to damaging high power electromagnetic rays. As you can imagine LIDAR is a particularly valuable technology both in the field of archaeology and beyond. Unsurprisingly, intellectual property relating to LIDAR has already been the subject of much contention highlighting the importance of a strong intellectual property portfolio.
Whilst the abovementioned technologies are great for investigating interesting areas, how far have we come in identifying new areas of interest? Thankfully, we don’t need a human to walk to the end of the earth and back to find each site with modern advancements technology. Google Earth provides worldwide satellite imagery, which can be analysed to find interesting archaeological finds and in some cases even buried treasure!
The biggest problem with satellite imagery and LIDAR systems is simply finding people to analyse the vast quantities of data produced. The use of crowd sourcing has been attempted to analyse the data, but there is still a long way to go. Maybe we’ll soon see some patents relating to artificial intelligence to help in analysing all of the data as part of the “Fourth Industrial Revolution”, which was discussed at the EPO conference on patenting Artificial Intelligence.