Eliminating multiple responses in a grating lobe antenna array

Claim 1

AN ANTENNA SCANNING ARRANGEMENT FOR USE WITH TRANSMIT AND RECEIVE ANTENNA ARRAYS COMPRISING (A) A TRANSMIT AND RECEIVE ARRAY EACH HAVING A PLURALITY OF ANTENNA ELEMENTS THEREON; (B) SAID ELEMENTS ON EACH ARRAY BEING PREDETERMINEDLY POSITIONED SO AS TO CREATE A TRANSMIT PATTERN HAVING A SINGLE MAIN LOBE AND A RECEIVE PATTERN HAVING A PLURALITY OF SPACED GRATING LOBES; (C) FIRST STEERING MEANS FOR STEERING SAID MAIN LOBE OF SAID TRANSMIT PATTERN OVER A TOTAL ANGULAR AREA TO BE SCANNED; (D) SECOND STEERING MEANS FOR STEERING EACH OF SAID GRATING LOBES OF SAID RECEIVE PATTERN OVER AN ANGULAR SECTOR WHICH IS SUBSTANTIALLY SMALLER THAN SAID TOTAL AREA, SAID GRATING LOBES SPANNING AN ANGULAR AREA WHICH IS SUBSTANTIALLY EQUAL TO SAID TOTAL AREA; (E) CONTROL MEANS FOR CONTROLLING SAID FIRST AND SECOND STEERING MEANS SO THAT THE POINT OF MAXIMUM AMPLITUDE OF SAID MAIN LOBE OF SAID TRANSMIT PATTERN MAY BE SELECTIVELY ALIGNED WITH THE POINT OF MAXIMUM AMPLITUDE OF ANY ONE GRATING LOBE OF SAID RECEIVE PATTERN SO AS TO PRODUCE AN UNAMBIGUOUS PRODUCT PATTERN HAVING A SINGLE REINFORCED LOBE; AND (F) SAID CONTROL MEANS INCLUDING MEANS FOR COORDINATING THE MOVEMENT OF SAID ALIGNED MAIN AND GRATING LOBES SO THAT SAID ANGULAR SECTOR MAY BE CONTINUOUSLY SCANNED.