The Border Patrol has been using ground sensors since the 1950s and I believe they are testing the ground radars as we speak. The problem is they dont have enough of the stuff leaving large areas with little or no coverage. Ask an agent what kind of technology they need and they will tell you more sensors and better IR cameras. So what does DHS buy, a 14 million dollar Predator UAV designed for a completely different mission.
I think that the Border Patrol may need to become more like the Coast Guard.
Please no. The Border Patrol already has more authority to enforce federal law than USCC including Title 8 & 18 (immigration) Title 19 (customs) and Title 21 (delegated from DEA). Placing them under the UCMJ would not do them any favors either.
The USBP makes more arrests per agent (also with the fewest civil rights allegations) than any other law enforcement agency in the world. There are just not enough of them.
You are absolutely right however, there is no silver bullet to solving this more agents or even the National Guard alone will not be enough. We need the proper mix of agents, technology and tactual infrastructure (fences etc.) to effect real and sustained border security. Additionally interior enforcement closing the jobs magnet that drives this activity will be a critical element.
A predator doesn't seem like the right tool for the job. Something smaller and shorter legged (and cheaper) would be better. It would be under the control of local BP agents, not some remote "Surveillance section". Plenty of those sorts available. Some not much larger than a hobby model airplane, but still able to carry IR or Video cameras, with the required downlink.