초록 ▼

A method and apparatus for use in a hybrid position location system. The method and apparatus combines measurements from Global Positioning System (GPS) and terrestrial transceiver stations to compute the location of a device. An algebraic solution to hybrid position location system equations is out

A method and apparatus for use in a hybrid position location system. The method and apparatus combines measurements from Global Positioning System (GPS) and terrestrial transceiver stations to compute the location of a device. An algebraic solution to hybrid position location system equations is output from the method and apparatus. The method and apparatus determines the position of a device using a non-iterative method, as against the use of a conventional iterative least mean square method. The method of the present invention can be used to solve the location system equations in scenarios where a non-iterative solution is desirable. In certain scenarios, the location system equations may have two possible solutions. An iterative method would converge on one of the solutions, without any indication of the existence of the other ambiguous solution. Moreover, the iterative method may converge on the incorrect of the two ambiguous solutions. Use of the presently disclosed method and apparatus yields both the ambiguous solutions. The disclosed method may be followed up with iterative methods, using the solutions from the algebraic method as initial estimates of the device location for the iterative method. A different process can then select the correct solution. Thus, the algebraic method can be used to detect the existence of ambiguous solutions, and to find both solutions.

대표청구항 ▼

[ We claim:] [1.]1. A method for determining in a processing unit the location of a device including:a) receiving range information, pseudo-range information, and difference of arrival information related to a particular location sought to be determined, the range information being the distance betw

[ We claim:] [1.]1. A method for determining in a processing unit the location of a device including:a) receiving range information, pseudo-range information, and difference of arrival information related to a particular location sought to be determined, the range information being the distance between the location of the device and a first transmission point, the pseudo-range information being the distance between the location of the device and a second transmission point plus a clock bias, and the difference of arrival information being the difference between the time at which a reference signal transmitted from a third transmission point arrived at the location of the device and the time at which a second signal transmitted from a fourth transmission point arrived at the location of the device;b) using a plane-wave approximation to eliminate any unknown second order terms associated with the pseudo-range information;c) substituting a first quadratic variable for any unknown second order terms in the range information;d) constructing a coordinate frame with one of the transmission points associated with the range information, the pseudo-range information, or the difference of arrival information as the origin of the coordinate frame;e) expressing as a set of equations, the range difference of arrival, range, and pseudo-range information in terms of the newly constructed coordinate frame;f) substituting a second quadratic variable for the coordinates of the unknown location, thus placing the equation for the difference of arrival, range, and pseudo-range information in the same form;g) concatenating the equations for the range, pseudo-range and difference of arrival information into a single set of equations;h) expressing the coordinates of the location of the device and the time bias as a function of the quadratic variable;i) solving for the second quadratic variable, and thus determining two solutions for the location sought; andj) outputting the location sought.