A temporary grid system was established over the site and marked out using canes. The location of the grid was set out using an RTK GPS system theoretically accurate to some 0.01m and referenced to OS co-ordinates. Data was 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. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. Each data point is geographically referenced using an on-board Trimble RTK survey grade GPS system. Readings were taken at 0.125m centres along traverses 1.0m apart. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. The magnetometer survey has recorded magnetic responses that have been interpreted as being of possible archaeological interest. In the north of Area 1 numerous anomalies are visible which could possibly mark the locations of enclosures, ditches and pits, though many of these are located outside of the development area. Responses of uncertain origin have also been detected, some of which might indicate former ponds or clay pits, whilst most are likely to have been caused by variations in the underlying geology or natural processes. However, archaeological origins for some of the responses cannot be entirely discounted. Former field boundaries and land drains have also been marked in the survey. Amorphous zones of increased response are visible across the survey; they have been caused by variations in the underlying geology.
Thomas Cockcroft (Mon,) studied this question.