3886553 is referenced by 65 patents and cites 5 patents.

A method and system are disclosed for measuring the geographical position of emitters such as radio transmitters accurately, simply, and inexpensively. In a particular application, the radio transmitters, which emit pulse type signals, may be located on small boats, for use in case of trouble, or on emergency vehicles. Widely spaced trilateration receiver stations are positioned to cover a preselected area and to receive the emitted signals. The relative time of arrival of each individual signal pulse at the several receiver stations is digitized and transmitted by way of communication channels to a central processing unit. At the central unit the time of arrival pattern of the pulses from the several receivers is compared with a pattern recognition matrix of previously mapped data. The central unit, being capable of responding only to preselected signal patterns, eliminates signals which originate outside of the preselected field of view and produces emitter location coordinants in digital numbers.The pattern recognition matrix is in the form of a logic array arranged to represent predetermined, discrete time delay increments as reference points in the geographical space under observation. The logic array produces coarsely quantized time-variable signal outputs. These time-variable output signals are interpolated in an array of variable-gain weighting devices using a centroid computing technique to finely locate the geographical coordinates of the transmitter.The system and method described have application to locating positions both in geographic as well as in geometric coordinate space. In the latter, the time of arrival pulse patterns are derived from time encoded analogs of physical measurements from various sensors where the measured parameters have a continuous functional relationship. There is stored in the matrix relatively coarse reference data containing the functional pattern. The input data, being continuous or finely quantized, is applied to the matrix. By virtue of the interpolation array, a smooth measuring of the position of the sample in the functional space is produced. This position is then interpreted by the user of the system. Stated in another manner, the method of this invention enables the use of prestored functional information to give the equivalent result of having stored a large amount of reference data.

Coordinate locating method and system
Application Number
Publication Number
Application Date
March 15, 1973
Publication Date
May 27, 1975
Bates John K
Plumley & Tyner
G01s 05/04
G01S 05/06
G01S 01/02
G01S 01/00
View Original Source