Radar apparatus

Patent metadata

Field	Value
Publication number	US-9874627-B2
Application number	US-201414762172-A
Country	US
Kind code	B2
Filing date	Jan 21, 2014
Priority date	Jan 21, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

In a radar apparatus, whether or not a second target candidate associated with second target information satisfying a first condition in relation to a first target candidate is present is determined. When determined that the second target candidate is present, the first target information corresponding to the first target candidate is compared with the second target information corresponding to the second target candidate. The “first condition” is that distances and relative speeds match. As a result of the comparison, when a difference between the power at a frequency peak corresponding to the subject target candidate and the power at a frequency peak corresponding to the comparison target candidate is greater than a prescribed threshold, the subject target candidate is determined to be a false image. Meanwhile, when determined that the difference is the prescribed threshold or less, the subject target candidate is determined to be a real image.

First claim

What is claimed is:

1. A radar apparatus comprising:
transmitting means for transmitting exploration waves;
a first receiving means for acquiring, as first reception signals, signals corresponding to signal waveforms respectively received by a plurality of first antenna elements disposed at a first interval prescribed in advance;
a first calculating means for:
detecting, based on the first reception signals, respective first target candidates for at least one target that has reflected at least one of the exploration waves, and
calculating first target information, for each first target candidate, including at least a signal level of the first reception signal corresponding to the first target candidate, a first distance that is the distance to the first target candidate, and a first orientation that is the orientation in which the first target candidate is present and is detected by an electronic scanning method;
a second receiving means for acquiring, as second reception signals, signals corresponding to signal waveforms received by a plurality of second antenna elements disposed at a second interval that is narrower than the first interval;
a second calculating means for:
detecting, based on the second reception signals, respective second target candidates for at least one target that has reflected at least one of the exploration waves, and
calculating second target information, for each second target candidate, including at least a signal level of the second reception signal corresponding to the second target candidate, a second distance that is the distance to the second target candidate, and a second orientation that is the orientation in which the second target candidate is present and is detected by an electronic scanning method;
a comparing means for:
setting, as at least one subject target candidate, at least one first target candidate among the first target candidates detected by the first calculating means, the at least one subject target candidate having at least the first distance that matches the second distance included in the second target information calculated by the second calculating means, and
comparing the first target information of the at least one subject target candidate with the second target information including one of the second distances that matches the first distance of the at least one subject target candidate, at least one of the second distances that matches the first distance of the at least one subject target candidate being referred to as a matched second distance; and
a determining means for determining whether the at least one subject target candidate is a real image or a false image based on the result of comparison by the comparing means,
wherein:
the determining means is configured to:
determine whether one of a first condition and a second condition is satisfied,
the first condition being that:
a difference between the signal level of the first reception signal of the at least one subject target candidate and the signal level of the second reception signal corresponding to the matched second distance is outside a prescribed range, and
a difference between the first orientation included in the first target information of the at least one subject target candidate and the second orientation included in the second target information including the matched second distance is outside a prescribed angle range determined in advance,

the second condition being that:
the difference between the signal level of the first reception signal of the at least one subject target candidate and the signal level of the second reception signal corresponding to the matched second distance is within the prescribed range, and
the first orientation included in the first target information does not match the second orientation included in the second target information including the matched second distance; and

determine that a result of determination of whether the at least one subject target candidate is a real image or a false image is suspended as an uncertain determination when determining that one of the first and second conditions is satisfied.

2. The radar apparatus according to claim 1 , wherein:
the determining means is a means for determining that the at least one subject target candidate is a real image when a difference between the signal level of the first reception signal of the at least one subject target candidate and the signal level of the second reception signal corresponding to the matched second distance is within a prescribed range prescribed in advance.

3. The radar apparatus according to claim 2 , wherein:
the determining means is a means for determining that the at least one subject target candidate is a real image when the first orientation included in the first target information matches the second orientation included in the second target information including the matched second distance.

4. The radar apparatus according to claim 2 , wherein:
the determining means is a means for determining that the at least one subject target candidate is a false image when:
the difference between the signal level of the first reception signal of the at least one subject target candidate and the signal level of the second reception signal corresponding to the matched second distance is outside the prescribed range, and
the difference between the first orientation included in the first target information of the at least one subject target candidate and the second orientation included in the second target information including the matched second distance is within a prescribed angle range determined in advance.

5. The radar apparatus according to claim 2 , wherein:
the transmitting means is a means for transmitting continuous waves that are frequency modulated along a time axis as the exploration waves;
the first calculating means is a means for calculating, for each first target candidate, the first target information including a first relative speed that is a relative speed in relation to the first target candidate;
the second calculating means is a means for calculating, for each second target candidate, the second target information including a second relative speed that is a relative speed in relation to the second target candidate; and
the comparing means is a means for setting, as the at least one subject target candidate, at least one first target candidate having the first relative speed that matches the second relative speed included in the second target information.

6. The radar apparatus according to claim 2 , comprising:
an evaluation value calculating means for calculating an evaluation value that increases as the likelihood of the at least one subject target candidate being a real image increases, based on the determination results from the determining means; and
an output means for outputting outside the radar apparatus, information indicating that the at least one subject target candidate is a real image, with the at least one subject target candidate as a confirmed target that is confirmed to be a target, when the evaluation value calculated by the evaluation value calculating means is equal to or greater than a prescribed threshold prescribed in advance, and information related to the confirmed target.

7. The radar apparatus according to claim 6 , wherein:
the transmitting means is a means for repeatedly transmitting the exploration waves at a in prescribed measurement cycles;
the first calculating means is a means for detecting, based on the first reception signals, the respective first target candidates for at least one target that has reflected at least one of the exploration waves, each time the transmitting means transmits the exploration waves;
the second calculating means is a mea

Assignees

• Denso Corp

Inventors

• Shimizu Koji

Classifications

• G01S13/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) · CPC title

• G01S13/931

  of land vehicles · CPC title

• G01S13/584

  adapted for simultaneous range and velocity measurements · CPC title

• G01S13/34 Primary

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S7/35

  Details of non-pulse systems · CPC title