A temporary grid system was established over the site and marked out using canes. The location of the grid will was set out using an RTK GPS system theoretically accurate to some 0.01m and referenced to OS co-ordinates. Hand Held: Data was collected using a Bartington Grad 601-2. The instrument consists of two paired sensors (see below) and readings are logged at 0.25m centres along traverses 1.0m apart across 30m grids. Two sensors mounted 1m horizontally apart and very accurately aligned to nullify the effects of the earth's magnetic field. Cart: Data was also collected using a cart carrying four paired Bartington magnetic sensors. Four sensors mounted 1m horizontally apart and very accurately aligned to nullify the effects of the earth's magnetic field. Each data point is geographically referenced using an on-board Trimble RTK survey grade GPS system. Readings will be taken at 0.125m centres along traverses 1.0m apart. The collection of data provides an appropriate methodology balancing cost and time with resolution as per Historic England guidelines. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. The magnetometer survey has not recorded any magnetic responses that could be interpreted as being of definite archaeological interest. An evaluation south of the site revealed numerous features belonging to multiple phases of activity; some of these features appeared to extend into the current site. However, the survey has failed to detect any evidence of these features; this may be due to a lack of magnetic variation between the fills and the surrounding natural or possibly because the features have been ploughed out. Uncertain anomalies have been plotted in the data, while archaeological origins cannot be entirely discounted, the majority of these are probably due to natural / agricultural processes or deeply buried ferrous debris. The routes of land drains have been marked in all three fields.
Thomas Cockcroft (Wed,) studied this question.
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