Pulse radar device

Patent metadata

Field	Value
Publication number	US-10754019-B2
Application number	US-201715720936-A
Country	US
Kind code	B2
Filing date	Sep 29, 2017
Priority date	Mar 31, 2015
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

The objective of the present invention is to use a simple circuit configuration and simple signal processing to provide a pulse radar device with which it is possible to reduce the impact of local signal carrier leakage on a received signal, and which makes it possible to perform high precision angle measurement using a multi-beam system. In order to measure the angle of an object, a pulse radar device is provided with at least two receiving antennas, and a reception circuit is provided with a signal selection switch for selectively switching between received signals received by the receiving antennas. The received signal contains a local signal leakage component, and a DC level of the received signal varies with the switching of the signal selection switch. In order to eliminate the impact of such DC level variations, a high-pass filter is disposed between a mixer and a frequency analyzer.

First claim

What is claimed is:

1. A pulse radar device, comprising:
a continuous wave generation circuit generating a continuous wave of a prescribed high frequency;
a transmission circuit receiving the continuous wave generated by the continuous wave generation circuit and modulating the continuous wave into a pulse signal;
a transmitting antenna repeatedly emitting the pulse signal from the transmission circuit into space at a prescribed emission period;
two or more receiving antennas receiving reflected signals from the pulse signal emitted from the transmitting antenna reflecting off of an object to be measured;
two or more amplifiers respectively amplifying the received reflected signals that have been received by the two or more receiving antennas so as to output respective amplified signals;
a signal selection switch receiving the respective amplified signals and switching between said respective amplified signals at a prescribed switching period so as to sequentially select and output the amplified signals originating from one of the receiving antennas at the prescribed switching period;
a mixer receiving said selected amplified signals sequentially outputted from the signal selection switch, the mixer down-converting said selected amplified signals by using the continuous wave input from the continuous wave generation circuit so as to output a baseband signal;
a frequency analyzer analyzing the baseband signal from the mixer and outputting information about the object detected from the baseband signal; and
a high pass filter provided after the signal selection switch and before the frequency analyzer, the high pass filter causing DC and other low frequency components that are lower than a prescribed frequency in the baseband signal to be removed before reaching the frequency analyzer,
wherein the prescribed emission period of the pulse signal repeatedly outputted from the transmitting antenna is divided into Tmeas and Twait, where Tmeas is a measuring period at least as long as a time it would take for the pulse signal to reach and be reflected off of the object if the object were located at a prescribed maximum measurable distance, and Twait is a remaining period of the emission period, and
wherein the signal selection switch switches between said respective amplified signals at a point in time within Twait.

2. The pulse radar device according to claim 1 , wherein the high pass filter is provided between the mixer and the frequency analyzer.

3. The pulse radar device according to claim 2 , wherein a cutoff frequency of the high pass filter is higher than a frequency set by the prescribed switching period at which the signal selection switch sequentially selects and outputs the one of the respective amplified signals.

4. The pulse radar device according to claim 1 , wherein a cutoff frequency of the high pass filter is higher than a frequency set by the prescribed switching period at which the signal selection switch sequentially selects and outputs the one of the respective amplified signals.

5. The pulse radar device according to claim 4 , further comprising:
a distributor distributing said one of the respective amplified signals sequentially outputted from the signal selection switch into two signals,
wherein the mixer is an IQ mixer receiving the two signals that have been distributed by the distributor and down-converting the two received signals into an I component baseband signal and a Q component baseband signal, respectively.

6. The pulse radar device according to claim 4 , wherein the frequency analyzer detects at least a direction in which the object is located relative to a position of the pulse radar device.

7. The pulse radar device according to claim 4 , wherein the high pass filter has a capacitor.

8. The pulse radar device according to claim 1 , further comprising:
a distributor distributing said one of the respective amplified signals sequentially outputted from the signal selection switch into two signals,
wherein the mixer is an IQ mixer receiving the two signals that have been distributed by the distributor and down-converting the two received signals into an I component baseband signal and a Q component baseband signal, respectively.

9. The pulse radar device according to claim 8 , wherein the frequency analyzer detects at least a direction in which the object is located relative to a position of the pulse radar device.

10. The pulse radar device according to claim 1 , wherein the frequency analyzer detects at least a direction in which the object is located relative to a position of the pulse radar device.

11. The pulse radar device according to claim 1 , wherein the high pass filter has a capacitor.

12. A pulse radar device, comprising:
a continuous wave generation circuit generating a continuous wave of a prescribed high frequency;
a transmission circuit receiving the continuous wave generated by the continuous wave generation circuit and modulating the continuous wave into a pulse signal;
a transmitting antenna repeatedly emitting the pulse signal from the transmission circuit into space at a prescribed emission period;
two or more receiving antennas receiving reflected signals from the pulse signal emitted from the transmitting antenna reflecting off of an object to be measured;
two or more amplifiers respectively amplifying the received reflected signals that have been received by the two or more receiving antennas so as to output respective amplified signals;
a signal selection switch receiving the respective amplified signals and switching between said respective amplified signals at a prescribed switching period so as to sequentially select and output the amplified signals originating from one of the receiving antennas at the prescribed switching period;
a mixer receiving said selected amplified signals sequentially outputted from the signal selection switch, the mixer down-converting said selected amplified signals by using the continuous wave input from the continuous wave generation circuit so as to output a baseband signal;
a frequency analyzer analyzing the baseband signal from the mixer and outputting information about the object detected from the baseband signal; and
a high pass filter provided after the signal selection switch and before the frequency analyzer, the high pass filter causing DC and other low frequency components that are lower than a prescribed frequency in the baseband signal to be removed before reaching the frequency analyzer,
wherein for every one or more of the prescribed emission period of the pulse signal that is repeatedly outputted from the transmitting antenna, a pair of a measuring period and a non-measuring period is provided for the frequency analyzer,
wherein the measuring period is at least as long as a time it would take for the pulse signal to reach and be reflected off of the object if the object were located at a prescribed maximum measurable distance,
wherein the frequency analyzer analyzes the baseband signal generated from the reflected signals that were received during the measuring period so as to detect the information about the object, but does not analyze or receive the baseband signal generated from the reflected signals that were received during the non-measuring period, and
wherein the signal selection switch switches between said respective amplified signals at a point in time within the non-measuring period.

13. The pulse radar device according to claim 12 , wherein the high pass filter is provided between the mixer and the frequency analyzer.

14. The pulse radar device according to claim 13 , wherein a cutoff frequency of the

Assignees

• Furukawa Electric Co Ltd
• Furukawa Automotive Systems Inc

Inventors

• Ishida Yoshiyuki
• Aoyagi Yasushi
• Yano Hiroyasu

Classifications

• G01S13/42 Primary

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

• G01S7/2886

  using I/Q processing · CPC title

• G01S7/02

  of systems according to group G01S13/00 · CPC title

• G01S13/44 Primary

  Monopulse radar, i.e. simultaneous lobing · CPC title