The Nobel Prize in Physics was awarded this week to three scientists, two of whom invented the charge-coupled device, CCD
This PDF is the public information on the Nobel Prize in physics. Charge-coupled devices have been used for various imaging devices including the Kitt Telescope and the Hubble which are mentioned in the link below. Note that CCD`s can be used in ordinary cameras or in telescopes and in various infrared devices. These cameras are used in satellites and in unmanned drones as well. Night-sight equipment allows folks “to see in the dark” by using infrared images. A warm body can be seen in the cold, dark night.
The Nobel link does not mention spy imaging as one of the uses for CCD`s but it is. When I Googled my rural address a few months ago, I saw an image of my house with a deer in the front yard. . . damn deer. The image was clearly taken by satellite.
The CCD was invented in 1969, forty years ago, so there is no reason that a virtual fence cannot work. It is only a lack of will. If Google can do it, our government can do it. That is not to say that a virtual fence is the best solution to closing our borders. It is simply to state that it is possible despite open-borders noise to the contrary.