There are drone jammers that block radio frequencies and GPS signals in a area making the used drone inoperable. (<a href="https://crab.wordpress.com/2010/02/11/how-to-down-a-drone/" rel="nofollow">https://crab.wordpress.com/2010/02/11/how-to-down-a-drone/</a>)<p>These devices are used at film sets and important buildings which makes it probable that they are a measure to protect the president.
There must be ways this is already covered. I'd be surprised if the president does not already have some level of protection from a mortar being fired where he is due to speak. There must be some kind of mobile in-air intercept method for smaller objects.<p>Perhaps mini missiles or those gattling guns they have on navy ships. The SS must be able to afford a few vans with these mounted around a perimeter. I just googled mortar defence and they are working on lasers that can stop these in air too.<p>Source: I know nothing.
My take - it's a growing pain for secret service.
My approach - take it out at source/planning/chatter stage.
When drone is up in the air at alternative controlled frequency or purely auto controlled with or without GPS - it's a bit too late.<p>It is an issue.