Monopulse phased array system

• US 6,618,008 B1
• Filed: 02/04/2002
• Issued: 09/09/2003
• Est. Priority Date: 02/18/1999
• Status: Expired due to Fees

• Current Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Original Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Inventors: Scholz, John Arthur
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/913,757
• Time in Patent Office: 582 Days
• Field of Search: 342/80, 342/149, 342/427
• US Class Current: 342/427
• CPC Class Codes: G01S 13/426 Scanning radar, e.g. 3D radar G01S13/66 takes precedence
• CPC Class Codes: G01S 13/4409 HF sub-systems particularly adapted therefor, e.g. circuits for signal combination multi-lobing aerials or aerial systems H01Q25/00
• CPC Class Codes: G01S 13/4463 using phased arrays
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems

Abstract

A monopulse phased array system comprises antenna elements with T/R modules controlled a beam steering computer. The space in which the antenna elements are arranged is divided into quadrants which are defined relative to the main axis of the radar beam. From the signals received by means of separate antenna elements, sum signals and first and second angle difference signals are derived: After combination of these signals delivered by the T/R modules, control signals are obtained for resteering the radar beam generated under the control of the computer mentioned. Each of the T/R modules is provided with two 180° phase shifters for determining the angle difference signals. After rotation of the radar beam, in the T/R modules of the antenna elements which are located in sectors whose sign of the axis direction perpendicular to the axis direction of the radar beam has changed through the rotation, a phase rotation of 180° is effected in the first angle difference signal and/or in the second angle difference signal.

Claims

1. A monopulse phased array system comprising antenna elements, each of which is connected to a corresponding transmitter/receiver (T/R) module operating under control of a beam steering computer (BSC), wherein each T/R module receives a transmission signal for forming a transmitting beam, and wherein a set of three signals including a sum signal, an azimuth difference signal, and an elevation difference signal, are derivable for each antenna element from reflection signals corresponding to reflections of the transmitting beam, wherein an least one combination unit derives, for each of the set of three signals derivable for each antenna element, a total sum signal, a total elevation angle difference signal and a total azimuth angle difference signal, from which regulation signals for are obtained for resteering the transmitting beam generated under the control of the beam steering computer, and wherein the monopulse phased array system further comprises:

an antenna arrangement space wherein the antenna elements are arranged into quadrants defined relative to a main axis of the transmitting beam, and wherein axes defined for determining the elevation and azimuth angle difference signal are perpendicular to the main axis of the transmitting beam, wherein

each of the T/R modules includes a 180°

phase shifter, for determining the elevation angle difference signal and for determining the azimuth angle difference signal, and wherein

when the transmitting beam after rotation has been directed at a target, the T/R modules are controllable such that, for each antenna element, a phase of shift of 180°

is executed in the elevation difference signal and the azimuth angle difference signal in the T/R modules of the antenna elements located in sectors whose sign of the axis direction perpendicular to the axis direction of the transmitting beam has changed through the rotation.

2. A monopulse phased array system according to claim 1, wherein a single combination unit processes reflection signals from antenna elements for each of the three signals derivable for each antenna element.

3. A monopulse phased array system according to claim 2, wherein each of the transmitter/receiver modules is provided with switching means for selectively feeding the elevation angle difference signal and azimuth angle difference signal shifted 180°

, to its respective combination unit.