Interferometer-type radar

• US 7,394,422 B2
• Filed: 12/19/2005
• Issued: 07/01/2008
• Est. Priority Date: 12/24/2004
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Nohmi, Hitoshi
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US11/303,942
• Publication Number:
  US 20060220946A1
• Time in Patent Office: 925 Days
• Field of Search: 342/90, 342 95- 97, 342107-116, 342/133, 342/139, 342/146, 342/147, 342/156, 342/192, 342/196, 342/417, 342/424
• US Class Current: 342/107
• CPC Class Codes: G01S 13/536 using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/9064 Inverse SAR [ISAR]
• CPC Class Codes: G01S 2013/0254 Active array antenna
• CPC Class Codes: G01S 7/025 involving the transmission of linearly polarised waves
• CPC Class Codes: G01S 7/35 Details of non-pulse systems

Abstract

A transmitter for transmitting signals to targets and a receiver for receiving signals reflected from targets are included. The transmitter outputs CW signals for detecting direction and velocity of the target. The receiver performs: a function of receiving signals reflected from targets with a plurality of receiving antennas at the same time as transmitting from the transmitter, and performing spectral analysis with respect to receiving signals to thereby classify them by velocity component; a function of correlating signals of the receiving antenna systems; a function of integrating the signals correlation-processed; and a function of obtaining phase fronts of signals made incident on an antenna face from the phase differences of signals between receiving antennas, and performing two-dimensional FFT to the outputs to thereby measure the direction and velocity of the target.

Claims

1. An interferometer-type radar comprising:

a transmitter for transmitting a signal to a target; and

a receiver for receiving a reflection signal reflected from the target, wherein

the transmitter includes a function of outputting a continuous wave (CW) signal for detecting direction and velocity of the target from a transmitting antenna, and the receiver includes;

a function of receiving a reflection signal reflected from the target with a plurality of receiving antennas at a same time as transmitting from the transmitter, performing spectral analysis with respect to receiving signals, and classifying the receiving signals by velocity component;

a function of performing correlation processing between signals of receiving antenna systems;

a function of integrating signals which have been correlation-processed; and

a function of performing two-dimensional fast fourier transform (FFT) to an output which has been integration-processed, and measuring an a direction and the velocity of the target.

5. The interferometer-type radar, as claimed in claim 1, wherein in the transmitter, a plurality of transmitting antennas connected to a plurality of transmitting modules are aligned in a matrix, and a transmitting signal, in which a beam width and a beam direction thereof are adjusted by a phase shifter of the transmitting module, is outputted from the transmitter.

7. The interferometer-type radar, as claimed in claim 1, wherein in the receiver, a plurality of receiving antennas are aligned in a T shape on an antenna face, and a space resolution is expanded by a dimension of the T shape.

9. The interferometer-type radar, as claimed in claim 1, further comprising an image display unit,

wherein the image display unit images outputted images from the receiver by overlapping them to thereby display direction, distance and velocity of the target, high-accuracy distance to the target at an instant time, and an ISAR image of the target by combining them.

2. An interferometer-type radar comprising:

a transmitter for transmitting a signal to a target; and

a receiver for receiving a reflection signal reflected from the target,

wherein the transmitter includes a function of outputting a frequency-modulated continuous wave (FMCW) signal for detecting velocity of the target from a transmitting antenna, and

the receiver has includes;

a function of receiving a reflection signal reflected from the target with a plurality of receiving antennas at a same time as transmitting from the transmitter, performing spectral analysis with respect to receiving signals which are frequency-converted with a signal same as a transmitting signal of FMCW, and classifying the receiving signals by distance component;

a function of performing correlation processing between signals of receiving antenna systems;

a function of integrating signals which have been correlation-processed; and

a function of performing two-dimensional FFT to an output which has been integration-processed and measuring the direction and the velocity of the target.

3. The integration-type radar, as claimed in claim 2, wherein the receiver further includes:

a function of receiving a reflection signal reflected from the target with a plurality of receiving antennas at a same time as transmitting from the transmitter, and performing frequency-correction, in which a Doppler shift caused by a velocity component and a positional change are corrected, to receiving signals which are frequency-converted with a signal same as the transmitting signal of FMCW by using velocity data of a specific target for which ranging is to be performed;

a function of performing spectral analysis in detail with respect to the signals which are frequency-corrected, and obtaining with high accuracy distance information which is converted to a frequency.

4. The interferometer-type radar, as claimed in claim 2, wherein the transmitter transmits an FMCW transmitting signal, which is phase-synchronized with a reference signal generated, from the transmitting antenna, and outputs the reference signal to the receiver, and

the receiver performs, by using the reference signal outputted from the transmitter as a common signal, frequency conversion and inverse synthetic aperture radar (ISAR) processing with respect to the reflection signal.

6. The interferometer-type radar, as claimed in claim 2, wherein in the transmitter, a plurality of transmitting antennas connected to a plurality of transmitting modules are aligned in a matrix, and a transmitting signal, in which a beam width and a beam direction thereof are adjusted by a phase shifter of the transmitting module, is outputted from the transmitter.

8. The interferometer-type radar, as claimed in claim 2, wherein in the receiver, a plurality of receiving antennas are aligned in a T shape on an antenna face, and a spatial resolution is expanded by a dimension of the T shape.

10. The interferometer-type radar, as claimed in claim 2, further comprising an image display unit,

wherein the image display unit images outputted images from the receiver by overlapping them to thereby display direction, 5 distance and velocity of the target, high-accuracy distance to the target at an instant time, and an ISAR image of the target by combining them.

11. An interferometer-type radar comprising:

a transmitter for transmitting a signal which is changed by a constant frequency change rate k and repeated in a cycle T;

a receiver having a heterodyne function in which a signal reflected from a target is frequency-converted with a local origination signal, having one of a timing completely same as said transmitting signal, a timing which is phase-synchronized, which is changed by a frequency change rate k and repeated in a cycle T; and

an analog-to-digital (A/D) converter for digitizing with a sample frequency F (F=kT) which is a product of the k and T.