GB1535338A - Radar systems - Google Patents

Abstract

1535338 Radar SIEMENS AG 13 Nov 1975 [13 Nov 1974] 46829/75 Heading H4D A radar system is provided with means for detecting manoeuvres of the target in the form of changes in the state of motion, in particular any transition from zero acceleration using a radar receiver incorporating two Kalman filters for the optimum estimation of a variable parameter, the first, for analysing low level target accelerations and the second for higher order accelerations. In Fig. 9, echo signals U are fed to radar receiver Ra where they are converted to digital signals Z k and applied to computer Re. Switch S, controlled by threshold detector Sw is set to connect signals Sk to a 1st low-level Kalman filter Fl, when no manoeuvre is detected. Filter Fl produces estimated values of a state vector #X k representative of the target's position from which a prediction value #X k - is derived. The innovation value I k is formed by the correlation means to establish the difference between each measured value and the relevant prediction value and fed to a shift register Sr of length N. To complete the correlation the numerical values stored in the shift registered positions are then multiplied by respective estimating error factors, S 0 , etc., and added to obtain a total which is applied to threshold detector Sw. Operation of switch S is made, to switch Kalman filters, when said threshold value is exceeded.