Radar system

• US 5,731,780 A
• Filed: 12/02/1991
• Issued: 03/24/1998
• Est. Priority Date: 12/11/1990
• Status: Expired due to Fees

• Current Assignee: Thales Nederland BV (Thales SA)
• Original Assignee: Hollandse Signaalapparaten BV (Thales SA)
• Inventors: Bleijerveld, Hendrik Cornelis
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US07/801,390
• Time in Patent Office: 2,304 Days
• Field of Search: 342/13, 342/123, 342/146, 342/147, 342/158, 342/180, 342/74, 342/75, 342/359
• US Class Current: 342/75
• CPC Class Codes: G01S 13/426 Scanning radar, e.g. 3D radar G01S13/66 takes precedence

Abstract

Radar system for the generation of two-dimensional or three-dimensional position indications of targets. Three-dimensional position indications are obtained by periodically canting the antenna about a canting axis, such that the antenna beam plane makes an angle with a normal on the earth'"'"'s surface and by combining azimuth data and range data obtained at different canting angles. For a radar system provided with dual-axis stabilization means, these means may also provide for the canting of the antenna means.

Claims

1. In a radar system for a generation, as required, of two-dimensional or three-dimensional position indications of targets present within a search volume of the radar system, the radar system comprising:

antenna means for the generation of a fan beam, the fan beam defining an antenna beam plane;

means for rotating, in azimuth, the antenna means at an antenna rotation time T; and

radar means, cooperating with the antenna means, for the generation of azimuth data and range data for the targets, the improvement comprising;

canting means for canting, about a canting axis, the antenna means, such that the antenna beam plane makes an angle of cant θ

with a normal on the earth'"'"'s surface, wherein the antenna means are provided with dual-axis stabilization means, and the dual-axis stabilization means also provide for the canting of the antenna means, and wherein the canting axis is substantially perpendicular to normal, and lies in the antenna beam plane; and

means for combining azimuth data and range data of targets, measured at different angles of cant θ

_i (i=1, . . . , n), to two-dimensional or three-dimensional position indications of the targets.

2. In the radar system according to claim 1, wherein the angle of cant θ

varies substantially stepwise in time.

3. In the radar system according to claim 2, wherein the angle of cant θ

varies substantially periodically in time.

4. In the radar system according to claim 3, wherein the period time of the angle of cant θ

is substantially nT (n =2, 3, 4, . . . ).

5. In the radar system according to claim 1, wherein the angle of cant varies substantially harmonically in time, and the period time of the angle of cant θ

is substantially nT (n=3, 4, 5, . . . ).

6. In the radar system according to either of claims 4 or 5, wherein for target azimuths φ

_mi, φ

_mi+1, . . . , φ

_k and distances R₁, R_i+1, . . . , R_k have been measured (i, k ε

N), and the azimuths φ

_mi, φ

_mi+1, . . . , φ

_k and the distances R₁, R_i+1, . . . , R_k have been measured at the angles of cant θ

_i, θ

_i+1, . . . , θ

_k, and an estimate of a height h_k of the targets is obtained from the angles of cant θ

_j, . . . , θ

_k, and an estimate of the height h_k is obtained from the angles of cant θ

_j, . . . , θ

_k, the measurements φ

_mj, . . . , φ

_mk and R_j, . . . , R_k where j ε

N;

i≦

j≦

k.

7. In the radar system according to either of claims 4 or 5, the improvement further comprising a track computer which continuously generates an estimate of a distance R to the targets and the azimuth φ

m and an estimate of a height of the targets is obtained from R, φ

, the instantaneous angle of cant θ and

the measured azimuth φ

_m.