Lots of people are talking about drones, otherwise known as unmanned aerial vehicles (UAV) or systems (UAS). There are more and more sensors being made available for these systems, and more contractors out there (you need to be CAA approved to fly these systems commercially) who can collect data across your site.
If you want to know whether a drone survey, aircraft campaign or satellite data would be best for your site then contact Geoger Ltd for impartial advice. Geoger can also manage the data collection campaign, contacting and liaising with the best contractor for the job in hand.
To get some extra information on UAV surveys and data processing (with a focus on point clouds), have a look at this article by Lewis Graham (no relation!) of GeoCue: http://www.lidarnews.com/content/view/10361/198/