A pulsed doppler search radar is disclosed in which range, bearing, and radial velocity are made available for display. The radar incorporates a capacitor matrix correlator and an improved method of range determination utilizing passive decoding circuitry and sequential unblanking of the capacitor correlator matrix drivers where required. Moreover, a passive implementation of the doppler direction algorithm is provided in which a summing circuit is implemented on the same printed circuit board utilized to form the capacitor correlator matrix. The capacitor matrix correlator and doppler direction summing circuit are manufactured through the use of face-to-face printed circuit boards having overlying sections patterned and registered so as to form the capacitive elements thereby simplifying the manufacture of the doppler correlator and doppler direction circuits.
This invention generally relates to navigation systems which seek to position in real time with appropriate accuracy one or more mobile platforms in reference to a known system of coordinates by the emission of signals into a propagation medium and processing them after detection. Broad-band, broad-beam signals are employed. All received signals convey phase encoded angular coordinate information which characterizes the particular signal path. When the angular coordinate information is used in conjunction with range determinations from detected signals, an especially useful navigation system is provided which can operate using only a single reference station.
A system for detecting a predictable time varying signal within a noisy environment. Rather than merely comparing the output of a matched filter implementation to a threshold, a parallel reference is also generated by autocorrelating the weighting function from the matched filter. The original output and this reference are both acted upon by a mathematical operator and the two then compared for closeness of fit using a Chi-Square Goodness of Fit Test, a Mean Square Error Test, or some other test for closeness of fit. A value indicates the closeness of the two curves and is then compared to a threshold to determine whether the signal of interest is present or not.
This invention generally relates to echo location or ranging systems in which the individual properties of targets or reflectors (such as range, bearing, elevation angle, relative velocity, impedance contrast, etc.) in a field of targets within some propagation medium are identified by the emission of signals into the propagation medium and processing of the detected reflections from the target field.
A method, and exemplary apparatus for practicing the method, is shown for operating a pulse radar to allow the radar ambiguity function of such radar to be modified by controlling the range and Doppler ambiguities due to the pulse waveform of such radar.
A matrix multiplier is described for multiplying sampled data in analog format by a matrix of stored values also in analog format and of positive or negative sign. The analog input quantity in the form of an electrical charge is applied to individual circuit elements making up the matrix. Each circuit element contains a capacitive storage means for encoding a stored value. An output term proportional to the product of the applied charge and the capacitance is produced in each circuit element. The input quantities are applied to the circuit elements in parallel by rows, and the output quantities are derived in parallel by columns to achieve matrix multiplication. In one form, the multiplier is a matrix of one stage charged coupled devices, each using a partitioned electrode storage site with the partitioning varying from element to element. The invention leads to a simple and high speed design. The invention is applicable to the computation of the Discrete Fourier Transformation.
