Unmanned aircraft have been used by the U.S. military for years. But now lightweight versions of drones are cheap enough for use by almost anyone, such as hobbyists interested in aerial photography. Drones also intrigue businesses like Amazon and Google, which are working on ways to use them for package deliveries. The Consumer Electronics Association estimates that the world’s annual drone sales will quadruple to nearly a million units in 2018. But before these vehicles are ready to land in a front yard to deliver a package, they will need better methods of sensing and avoiding airplanes and other objects, people, and each other. Here are a few of the projects that could pave the way for more widespread use of drones.

Human Operators

Until drones are advanced enough to avoid every obstacle, humans will play a big role in their safe operation. Realizing that many enthusiasts would be unwrapping affordable drones like the DJI Phantom or 3D Robotics IRIS+ during the holidays, the U.S. Federal Aviation Administration partnered with drone industry groups like the Small UAV Coalition to set some ground rules for hobbyists to follow until it issues more comprehensive regulations. A new website, knowbeforeyoufly.org, encourages enthusiasts to fly vehicles below 400 feet and to keep them in sight. Flights near airports, stadiums, and people are no-nos. The FAA also encourages hobbyists to take flying lessons and fly their drones with local clubs.

American companies and individuals profiting from drone operations face even stricter rules. They need the FAA’s explicit permission to use drones, and they must put a trained private pilot in charge of the controls. So far, only a few have gained these approvals, including oil companies operating in remote areas and a small number of movie studios, a farm, and a real-estate agent.

Seeing Danger

While today’s civilian drones need remote control from a person to avoid crashes, some new visual sense-and-avoid systems may allow the aircraft to take on some of that responsibility.

Three MIT grads at a startup called Skyd.io are developing a system that they hope will help drone operators keep the vehicles out of harm’s way and free up people to focus more on their photography. In a video, the team shows prototype software that allows a person to direct a drone with just a wave of a smartphone and navigate it around trees in a forest. Multiple cameras are rigged up to the drone, allowing it to see in all directions at once. Skyd.io unveiled its plans this month and aims to have a product for release within a year.

Germany’s Ascending Technologies makes drones to help companies inspect and survey industrial areas. Since introducing its first vehicles more than a decade ago, the company has developed a range of technologies like thermal flight cameras, laser scanners, and ultrasonic sensors to keep its drones from hitting objects. However, these components all have limitations and tend to work well only in controlled environments, says Ascending Technologies’ chief executive, Daniel Gurdan. By incorporating a tiny new camera from Intel, the company has recently enhanced the drones’ ability to detect depth—information that is crucial for onboard software that can change the vehicle’s course in real time to dodge hazards. Ascending Technologies and Intel demonstrated the technology at the International Consumer Electronics Show in Las Vegas by rigging a ring of six cameras onto several drones and sending them through an obstacle course.

Air Traffic Control Systems

Drones’ onboard sense-and-avoid capabilities will keep them from running into the family dog while delivering packages, but that’s just helpful for one mission. A more far-reaching system is needed to ensure that these vehicles stay away from each other and from planes already occupying the skies.

NASA is working on a new air traffic management system that will create digital lanes in the sky just for drones, says Parimal Kopardekar, the NASA Ames researcher in charge of building it. Relying on GPS, the vehicles would probably travel through these lanes at 400 or 500 feet above ground level. These corridors would be separated from airports, since aircraft may fly at that altitude during takeoff or landing.

Drones could be scheduled to take off and land in timed intervals and cross through the same areas of airspace at different altitudes to avoid collisions, the way planes do today. A highly automated system, rather than human air traffic controllers, would be responsible for tracking most of those movements.

The whole program will take several years to test, so a prototype for the system probably won’t be ready until 2019 at the earliest.

NASA invited companies to join the project last fall through a notice, which offers more information on the program. One company that has announced its involvement is Airware, based in San Francisco. Airware is developing software that will make it possible for different kinds of drones to communicate with each other and for the aircraft owners to plan and change routes. SkyWard is also working on technology that could be used in a future air traffic control system. Through a project called Urban SkyWays, the company wants to demonstrate a cloud-based information-sharing tool that will allow drone operators to track their flights and see a map of where the drones can safely fly. The company plans to test the system in Las Vegas, Vancouver, London, and its hometown of Portland, Oregon, to show how drones delivering packages, responding to emergencies, and inspecting industrial sites would coexist in urban areas.

The Takeaway

Sense-and-avoid technologies available for drones today may work in controlled environments, but many are still not versatile enough to automatically steer clear of obstacles during complicated missions like inspecting power lines or dropping off packages for delivery. As NASA develops a large-scale air traffic management system for drones, federal aviation regulators are due to step in to clarify or ease restrictions on their commercial use. In the meantime, tests of commercial drones are proceeding in countries with more open policies, such as Canada and Australia.