Method and system for detecting and combating covered ground targets

• US 4,675,677 A
• Filed: 08/19/1985
• Issued: 06/23/1987
• Est. Priority Date: 08/22/1984
• Status: Expired due to Fees

• Current Assignee: Messerschmitt-Boelkow-Blohm GmbH (Mercedes-Benz Group AG)
• Original Assignee: Messerschmitt-Boelkow-Blohm GmbH (Mercedes-Benz Group AG)
• Inventors: Blaha, Alfred, Detlefsen, Juergen, von Maydell, Ignaz
• Primary Examiner(s): Tubbesing, T. H.
• Assistant Examiner(s): Gregory, Bernarr Earl
• Application Number:
  US06/767,132
• Time in Patent Office: 673 Days
• Field of Search: 343/5 CM, 343/5 FT, 343/5 MM, 343/5 PD, 343/5 SA, 343/7 G, 342/25, 342/61-72, 342/195, 342/196
• US Class Current: 342/25.00A
• CPC Class Codes: G01S 13/9027 Pattern recognition for feature extraction
• CPC Class Codes: G01S 13/9041 Squint mode

Abstract

A system for manned or unmanned flying bodies detects covered or hidden targets on the ground by using relatively "longwave" radar radiation for immediately attacking such ground targets, which may be covered by trees for example, but located on a strip of ground extending with a given width below the flight path of the flying body travelling in low altitude flight. Four radar receiver antennas are equally spaced from each other along the wings of the flying body and one transmitter antenna is located between two pairs of receiver antennas. The receiver signals are submitted by a fast Fourier transformation for providing a wavefront reconstruction. The so transformed, received signals are then evaluated in accordance with the known SAR principle directly as the signals are received and transformed by correlation with expected signal functions, so-called reference function, for producing a control signal for the direct or indirect discharge of a weapon.

Claims

1. A method for detecting concealed ground targets with the aid of transmitter receiver means including transmitter antenna means and arrays of receiver antenna means installed on a flying body having a longitudinal roll axis extending in a forward flight direction, comprising the following steps:

(a) installing said transmitter antenna means and said arrays of receiver antenna means, operable in an operating frequency range of 500 to 1200 Mhz, on said flying body so that at least said receiver antenna means face forwardly and downwardly within a predetermined angular range relative to the horizontal coinciding with said longitudinal roll axis extending in said forward flight direction,

(b) spacing said arrays of receiver antenna means, in a direction extending across said forward flight direction, from one another at a spacing (Δ

L) which is substantially larger than one-half of the wave length corresponding to an operting frequency in said operating frequency range,

(c) storing in a memory on said flying body several reference signal functions which represent different target signatures,

(d) transmitting continuous wave signals through said transmitter antenna means and receiving reflected radar signals through said arrays of receiver antenna means,

(e) evaluating received radar signals reflected from a target in an azimuth plane in said forward flight direction by first sorting received radar signals according to angular sectors to produce sorted signals, and then applying a reconstruction procedure in accordance with a synthetic-aperture-radar principle to the sorted signals for producing a reconstructed signal function,

(f) and directly correlating said reconstructed signal function with said several reference signal functions for producing a control signal output signifying the presence of a concealed target.

2. The method of claim 1, further comprising using said control signal output for triggering a weapons carrier on said flying body for discharging a weapon substantially directly downwardly toward a detected target.

3. The method of claim 1, further comprising processing said reconstructed signal function so that said control signal output comprises target position information in addition to signifying the presence of a concealed target.