Advances in technology have enabled munitions such as missiles, bombs, and artillery shells to be much more precise. Satellite-aided navigation systems, such as the Global Positioning System (GPS), is one of the more recent advances and provides an accuracy of less than ten meters even at ranges of hundreds of miles. Such accuracy would have been unheard of fifty years ago, when bombs were dropped from airplanes using optical sights.
Although GPS-guided munitions are designed to be highly accurate, one disadvantage of such munitions is the cost of the circuitry, especially considering the circuitry in a missile is designed to be used only once. Additionally, reducing the weight and space required for navigation equipment generally improves performance of munitions. Furthermore, there may be environments or scenarios in which GPS-guided navigation is ineffective. Because the GPS frequencies are well known it is common for an adversary to attempt to interfere with or replace the satellite-based GPS signals with an erroneous signal. The GPS-based navigation equipment must be updated or re-designed to stay ahead of each electronic countermeasure deployed by an adversary. Lastly, GPS-guided munitions typically also use other types of navigation aids, such as radar altimeters and inertial navigation components such as gyroscopes and accelerometers. Such aids and components are subject to malfunction or failure, and providing component redundancy increases cost and weight of munitions using such components.
The concerns and disadvantages described above are applicable at least in part to the navigation of other aerial or ground-based platforms or craft. For example, unmanned aerial vehicles (UAVs) are routinely used by the military for surveillance, reconnaissance, communications, and ordnance delivery. Civilian uses of UAVs are just beginning to be realized. Reducing the cost, weight, required space, and complexity of navigation systems would be appreciated by designers and users of UAVs and other craft.
It is therefore an object of the invention to provide an accurate, reliable navigation solution usable by various types of mobile objects and craft.
Another object of the invention is to provide a navigation solution for various mobile platforms that reduces the cost, weight, space requirements, and complexity over known navigation solutions.
It is another object to provide a navigation solution for mobile platforms that is effective in reducing the impact of electronic countermeasures employed by an adversary.
A feature of the invention is radar tracking of a mobile platform by a friendly asset and communicating the radar-derived position to the mobile platform.
An advantage of the invention is reduced cost, weight, and space requirements of the mobile platform.