To view this item's National Grid Reference Number you need to be a subscriber. You can become a subscriber by visiting this page

Or login here if you are already a subscriber.

1 (0%) of Registered Dartefacters have visited this item. They are: SteveGrigg

Notes: This FBM was installed in the GPS era. Steve Grigg writes: “From 1989, OS installed and operated a combination of ‘Passive Stations’ and ‘Active Stations’ as part of the Global Positioning System calibration. Some OS ‘Passive’ GPS stations are known as FBM Aux (Auxiliary) and are geodetic quality ground markers (like the previous generation of FBMs) and are in user-accessible locations. (Note: Other ‘Passive Stations used are pillars and bolts from the previous geodetic survey periods). In the UK most of these ‘Passive Stations’ are within 20-35 km of each other. OS have a network of around 1000 ‘Passive Stations’ and around 180 ‘Active Stations” (which are sited at about 30 locations). At the ‘Active Stations’, GPS receivers constantly log readings allowing a very high level of positional accuracy to be achieved, without the need to physically occupy one of the ‘Passive Stations’. The ‘Passive Stations” are surveyed on a five-yearly basis but require the user’s own GPS reference receiver during the survey. On Dartmoor, there is a ‘Passive Station’ (FBM Aux type) at Yelverton, known as Yelverton FBM Aux.“

Reference: Dartmoor Explorations

The map below is set to a maximum zoom of 1:50k. To zoom into the map further (1:25k) you need to be a subscriber. You can become a subscriber by visiting this page.

Or login here if you are already a subscriber.