Accurate and precise surveying is essential and therefore preference is for a cart-based system with automatic RTK GPS logging, although, data collection using handheld gradiometers is also acceptable for magnetometer surveys.

As a minimum it is expected that:

• All survey techniques will follow the guidance set out by the CIFA, Historic England, and the European Archaeology Council (EAC)
• For handheld magnetometer surveys the standard survey resolution shall be no coarser than 1m x 0.25m (traverse lines 1m apart with data collected every 0.25m). For a cart-based system a higher resolution will be expected
• The maximum survey resolution for earth resistance surveys shall be no greater than 1m x 0.5m (traverse lines 1m apart, data collected every 0.5m)
• Instruments will be set up carefully to collect highest quality raw data to minimise the need for any post-survey processing
• The location of survey grids will be plotted using a GPS system accurate to within ±0.01m relative to the Ordnance Survey National Grid