When we think about GPS satellites, most of us think about how the typical consumer uses GPS in their vehicle to get from one place to another. In fact, many people rely so heavily on GPS that in the event of a map problem, some people have literally driven right off the road because they depend so heavily on GPS. While a significant GPS outage for your average consumer might be an annoyance, an outage for the military could be catastrophic.
The military uses a number of different types of weapons that rely on GPS signals to accurately track and destroy enemy targets. If the GPS satellite system were to go down due to accident or a military strike, GPS guided missiles, and bombs could be rendered ineffective. DARPA doesn't like the thought of military weapons rendered ineffective by taking down a few satellites that orbit unprotected in space.
Therefore, researchers at DARPA have been working on creating something called the TIMU, or Timing and Inertial Measurement Unit. This tiny chip has everything it needs on the single piece of silicon to navigate around the globe without relying on GPS satellites. The sensor has a six-axis IMU including three accelerometers and three gyroscopes. It also has a highly accurate master clock all packed into a space measuring only 10 mm.
DARPA says that the tiny piece of silicon can give hardware using it a near precise location. DARPA says that the little sensor works because it provides three pieces of information that are required to accurately guide anything to a desired destination. The three pieces of information are orientation, acceleration, and time. The chip DARPA designed uses six layers of silica and is only 50 microns thick. That is about thickness of a human hair with each of the six layers providing a different function depending on the sensor embedded there. The TIMU does have applications outside of military use and could allow for civilian GPS devices offering improved navigation indoors or underground where GPS satellites can't be used.
[via Element 14]