Atom interferometry for high precision navigation

High precision navigation is a key ability both in military and civilian applications. Precisions of a few meters and even centimetres are desirable when, e.g., tracking movements and to avoid obstacles. For most applications this is solved by using GPS signals. For more demanding applications a GPS signal combined with other sensor data enhances the positioning and makes it more robust. However, because most navigation systems rely on external signals like camera, radar or GPS satellite signals, they become vulnerable. These signals can in many circumstances be out of reach, disabled or jammed. A way to minimize the use of external signals is to navigate by inertial sensors. By using inertial sensors for measuring acceleration and rotation rates it is possible to keep track of the changes in position and orientation. The benefit of this method is that in principle only the starting position is needed to be known. All other positions are then calculated through accelerometer and gyroscope sensor data. These sensors can be kept well isolated and secure. Very few accelerometers and gyroscopes are sufficiently accurate to reliably navigate with high precision for a longer time. Best systems are found in submarines and intercontinental ballistic missiles that can reach a precision of about 100 m after navigating for one hour. More affordable and smaller sensors for inertial navigation still depends on GPS signals to have intermediate position updates, else the error will grow fast often reaching many thousands of meters. High precision accelerometers and gyroscopes are expensive and large. However, many applications would benefit of affordable, small size and high precision sensors. Not many technologies have the potential to reach these specifications and it is necessary to look at new emerging technologies. A technology that is on the uprise and has all qualifications for reaching all three specifications is chip size atom interferometers. It is predicted that the technology can deliver briefcase size sensors with the potential of inertial navigation with an error of only 2-5 meters after one hour of navigation. This incredible precision is beyond any current inertial navigation system and at the limit of what can be achieved with inertial navigation. Because of the high accuracy it has been suggested that these sensors can also be used for enhanced situation awareness where a warning is produced if a large mass is approaching. Atom chip interferometer technology is in a very early technological stage. However, table-top atom interferometers are reaching maturity in the field of gravity measurements and there are proof-of-concept experiments striving for inertial navigation. The maturity of atom based gravity measurements has produced at least two spin-off companies. In addition, several other companies are closely surveying the atom interferometer development and taking patents. In this survey we investigate the current status of atom interferometer technology, expected accuracies, noise factors and sensor trends. Our objective is to give an overview of the potential of atom interferometry and pinpoint its relation in accuracy compared to other technologies.