Patent ID: 7395030

Claim:
An adaptive control apparatus used by a radio apparatus having an array antenna for transmitting and receiving a radio frequency signal, the adaptive control apparatus adjusting directivity of the array antenna, comprising: a setting unit configured to set up parameters including a distance between the radio apparatus and a receiver that receives the radio frequency signal transmitted by the radio apparatus, a relative moving speed, and a moving direction of the receiver with reference to the radio apparatus; an evaluating unit configured to evaluate how much received power at one of the receiver and the radio apparatus changes after a predetermined period; and a weight control unit configured to adjust a plurality of weighting factors of a plurality of antenna elements contained in the array antenna; wherein the directivity is adjusted such that the amount of change of the received power is kept within fixed limits independent of the distance between the receiver and the radio apparatus and the setting unit further comprises: a first setting unit configured to set up first parameters including the distance between the radio apparatus and the receiver that receives the radio frequency signal transmitted from the radio apparatus, the relative moving speed, and the moving direction of the receiver with reference to the radio apparatus based on the signal received by the array antenna; a storage unit configured to store the parameters used in order to determine the weighting factor that is continuously updated, the storage unit being connected to an output of the first setting unit; a second setting unit configured to output second parameters that serve as estimated present parameters by using the parameters stored in the storage unit, and wherein the weight control unit: calculates the first weighting factor based on the first parameters and the second weighting factor based on the second parameters, and calculates a next weighting factor by setting the second weighting factor as an initial value, if an amount of difference between a direction of a first directivity, that may be realized b the first weighting factor, and a direction of a second directivity, that may be realized b the second weighting factor, is greater than a predetermined value.