# How does one use the Surveillance Fence feature in keeptrack.space?

keeptrack.space was mentioned in What would be a “big picture” understanding of how the orbits of Earth satellites are monitored? but I haven't visited the site since.

Running across this again today I noticed there seems to be several additional features. I lack a video game mentality and so baffled by the GUI-driven site, but I noticed the option Set/Hide Surveillance Fence. Clicking it generated a message to select a sensor so I chose CSpOC Sensors. I clicked Set/Hide Surveillance Fence again but nothing happens.

Question: What does the Surveillance Fence feature do? How can one use and make use of it?

## 1 Answer

If you select any sensor, clicking the "show surveillance fence" control shows the extent of the surveillance zone that sensor uses.

For example, Cape Cod gives a planar field, with a blank area west of the sensor:

And Diego Garcia gives a conic:

• Hmm... so my problem is that I can't see any satellites at all or the fence. For some reason everything seems to be turned off. I guess I'm having "operator error". sometimes I can get orbits to show up, but no dots i.stack.imgur.com/PEHmf.jpg Yours look great, thanks!
– uhoh
Jan 30 '20 at 9:44