Airborne GPS is now a commonly used add-on to a standard photo mission. By using a multiple frequency antenna mounted directly over the camera and survey grade GPS receiver connected to the camera center pulse output we can very accurately determine the position of the image when it was created. BPS has refined its techniques since 1993 and now uses state of the art equipment with reliable results. We work with certified survey companies to set the parameters for a flight so accuracies will meet the needs for the client and project. In general terms, the farther the roving station (airplane and receiver) is from the base station (manned receiver or CORS point) the less accurate position we will see after post processing. The accuracy required will depend on the type of end product and scale specifications. We can help coordinate the planning, but ultimately the project designer and surveyor must agree on the approach. The survey company will post process and format the data, providing their certification in the process.

In recent times, we have been able to initialize our AGPS flight within 10 miles of the base station and then work on the project staying within about 30 miles of the base. The newer receivers and post processing software are allowing these requirements to relax somewhat and low accuracy projects (for example high level orthos) can sometimes shortcut many of the hard rules of the past. The trending is to use multiple unmanned Continuously Operating Reference Stations (CORS) instead of deploying a person to the project site when possible. This reduces costs significantly and allows the flight crew to respond to unexpected weather breaks.

Download the AGPS project worksheet.