| Integer ambiguity is a problem with a single frequency continuous wave system in which the integer number of cycles is unknown.; Many continuous wave navigational systems are not capable of independently resolving the integer number of wavelengths in a range measurement. The fractional part of the range can be measured but the integer must be initially given and then tracked. If the number of ranges required to triangulate a fix exceeds the minimum, and if the mobile movement manifests significant spatial variability, the solutions will 'focus' at the correct position which in turn yields the appropriate integer for each range.; This work is based on an active navigation system or a passive navigation system with a single VHF signal. By using the fractional part of the radials, and the position of the beacons, all ambiguous solutions are reduced using spatial variation. All possible initial positions for the mobile will be tested. The correct initial position will be the one that has beacon-pair fixes focusing on the mobile's path. Typically if the mobile moved 1 km with one redundant beacon, the initial position can be found to within 15 cm.; This algorithm, the Ambiguity Reduction Process (ARP), not only eliminates the ambiguous solution, but also produces an estimate of the systematic error. It is suggested that this algorithm would find application in precise, short range, two-dimensional navigation systems. |
