RADAR APPARATUS

• US 20120223855A1
• Filed: 02/29/2012
• Published: 09/06/2012
• Est. Priority Date: 03/04/2011
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: KURONO, Yasuhiro, ASANUMA, Hisateru, SHINOMIYA, Tomohiro
• Granted Patent: US 9,128,174 B2
• Time in Patent Office: Days
• US Class Current: 342/146
• CPC Class Codes: G01S 13/00 Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
• CPC Class Codes: G01S 3/06 Means for increasing effective directivity, e.g. by combining signals having differently oriented directivity characteristics or by sharpening the envelope waveform of the signal derived from a rotating or oscillating beam antenna comparing amplitude of signals having differently oriented directivity characteristics to determine direction G01S3/16, G01S3/28
• CPC Class Codes: G01S 7/28 Details of pulse systems
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/2925 by using shape of radiation pattern
• CPC Class Codes: G01S 7/483 Details of pulse systems

Abstract

There is provided a radar apparatus of an electronic scan type configured to transmit an electric wave and calculate an angle of a target based on a phase difference of respective reception signals, thereby detecting a target position. An antenna unit transmits and receives the electric wave and provided with two transmission antennae. A transmission unit alternately transmits an electric wave having a first beam pattern and an electric wave having a second beam pattern from the two transmission antennae. First and second reception units calculate arrival angles and reception levels of reflected waves calculated from respective reception signals which are obtained by receiving the reflected waves by the first and second beam patterns. A comparison unit compares the reception levels by combining the arrival angles of the reflected waves. A determination unit determines whether a target actually exists at the arrival angles in accordance a comparison result.

Claims

1. A radar apparatus of an electronic scan type configured to transmit an electric wave and calculate an angle of a target based on a phase difference of respective reception signals which are obtained by receiving reflected waves at a plurality of receiving antennae, thereby detecting a target position, the radar apparatus comprising:

an antenna unit configured to transmit and receive the electric wave and provided with two transmission antennae;

a transmission unit configured to alternately transmit an electric wave having a first beam pattern and an electric wave having a second beam pattern from the two transmission antennae, the first beam pattern and the second beam pattern being different from each other;

a first reception unit configured to calculate an arrival angle and a reception level of a reflected wave calculated from respective reception signals which are obtained by receiving the reflected wave by the first beam pattern;

a second reception unit configured to calculate an arrival angle and a reception level of a reflected wave calculated from respective reception signals which are obtained by receiving the reflected wave by the second beam pattern;

a comparison unit configured to compare the reception levels calculated by the first and second reception units by combining the arrival angles of the reflected waves, and determine whether a level difference of the reception levels is a predetermined reception level difference or greater; and

a determination unit configured to determine whether a target actually exists at the arrival angles of the reflected waves in accordance a determination result of the comparison unit.

2. The radar apparatus according to claim 1, wherein the first beam pattern and the second beam pattern have the same beam pattern shape, a transmission axis of the first beam pattern is rightward inclined by a predetermined angle and a transmission axis of the second beam pattern is leftward inclined by the predetermined angle where a front of the radar apparatus is considered as 0°

.

3. The radar apparatus according to claim 2, wherein the first beam pattern and the second beam pattern have an overlapping area at the front of the radar apparatus.

4. The radar apparatus according to claim 3,

wherein the determination unit determines that the target actually exists at the arrival angles of the received reflected waves when an absolute value of the difference of the reception levels of the reflected waves received by the first and second reception unit is smaller than a reference level, and

wherein the determination unit determines that the target does not actually exist at the arrival angles of the received reflected waves when the absolute value of the difference of the reception levels of the reflected waves received by the first and second reception unit is larger than the reference level.

5. The radar apparatus according to claim 1, wherein the first beam pattern and the second beam pattern have the same transmission axis, the first beam pattern has a beam transmission width narrower than that of the second beam pattern and a transmission output higher than that of the second beam pattern and the first beam pattern and the second beam pattern have an overlapping area at the front of the radar apparatus.

6. The radar apparatus according to claim 5,

wherein the determination unit determines that the target actually exists at the arrival angles of the reflected waves when the reception level of the reflected wave received by the first reception unit is larger than the reception level of the reflected wave received by the second reception unit, and

wherein the determination unit determines that the target does not actually exist at the arrival angles of the reflected waves when the reception level of the reflected wave received by the first reception unit is equal to or smaller than the reception level of the reflected wave received by the second reception unit.

7. The radar apparatus according to claim 1, wherein the first beam pattern and the second beam pattern have the same transmission axis, the first beam pattern has a beam transmission width narrower than that of the second beam pattern and a transmission output equal to that of the second beam pattern and the first beam pattern and the second beam pattern have an overlapping area at the front of the radar apparatus.

8. The radar apparatus according to claim 7, wherein the determination unit determines that the target does not actually exist at the arrival angles of the received reflected waves when a difference of the reception levels of the reflected waves received by the first and second reception units is larger than a reference value.

9. A radar apparatus of an electronic scan type configured to transmit an electric wave and calculate an angle of a target based on a phase difference of respective reception signals which are obtained by receiving reflected waves at a plurality of receiving antennae, thereby detecting a target position, the radar apparatus comprising:

an antenna unit configured to transmit and receive the electric wave and provided with two transmission antennae;

a transmission unit configured to alternately transmit an electric wave having a first beam pattern and an electric wave having a second beam pattern from the two transmission antennae, the first beam pattern and the second beam pattern being different from each other;

a first reception unit configured to calculate an arrival angle and a reception level of a reflected wave calculated from respective reception signals which are obtained by receiving the reflected wave by the first beam pattern;

a second reception unit configured to calculate an arrival angle and a reception level of a reflected wave calculated from respective reception signals which are obtained by receiving the reflected wave by the second beam pattern;

a comparison unit configured to compare the reception levels calculated by the first and second reception units by combining the arrival angles of the reflected waves; and

a determination unit configured to determine whether a target actually exists at the arrival angles of the reflected waves in accordance a comparison result of the comparison unit.