Vehicle surroundings monitoring apparatus
View Patent ↗If a vehicle surroundings monitoring apparatus is equipped with four radars disposed at each of the four corners of the body of a vehicle in order to detect an object around the vehicle, the interfere of the radio waves of the radars likely to occur. As a result, the accuracy for detecting an object by the radars will deteriorate. Specifically, if two of detection areas are adjacent to each other of the radars overlaps with each other and the two of the radars transmits radio waves at the same time, the interfere of the radio waves will occur in the overlapping area. In view of this, the four radars are divided into two groups such that the detection areas of two radars within the group aren't adjacent to each other and transmission period of one of the groups and that of the other of the groups are repeated alternately.
1. A vehicle surroundings monitoring apparatus comprising:
four radars including a forward right radar, a forward left radar, a backward right radar, and a backward left radar, each of the radars performing object detection in a respective detection area around a vehicle by transmitting a radio wave and receiving a reflection wave generated as a result of reflection by an object of the transmitted radio wave, the forward right radar being disposed at a front right corner part of a body of the vehicle, the forward left radar being disposed at a front left corner part of the body, the backward right radar being disposed at a rear right corner part of the body, and the backward left radar being disposed at a rear left corner part of the body; and
a processor configured to:
control first diagonal radars including the forward right radar and the backward left radar to perform an operation of alternating, at a predetermined interval, a first transmission period for which each of the first diagonal radars transmits the radio wave in a synchronized manner and a first transmission stop period for which each of the first diagonal radars does not transmit the radio wave, and
control second diagonal radars including the forward left radar and the backward right radar to perform an operation of alternating, at the predetermined interval, a second transmission period for which each of the second diagonal radars transmits a radio wave in a synchronized manner and a second transmission stop period for which each of the second diagonal radars does not transmit the radio wave, in such a manner that the first transmission period and the second transmission period do not overlap each other.
2. The vehicle surroundings monitoring apparatus according to claim 1 , wherein said processor is configured to
set said first transmission period and said first transmission stop period to be equal in length to each other;
set said second transmission stop period in such a manner that the second transmission stop period overlaps completely with the first transmission period; and
set a second transmission period in such a manner that the second transmission period overlaps completely with the first transmission stop period.
3. The vehicle surroundings monitoring apparatus according to claim 2 , wherein said processor is configured to:
control radio wave transmission of said forward right radar;
control radio wave transmission of said forward left radar;
control radio wave transmission of said backward right radar; and
control radio wave transmission of said backward left radar, and wherein,
send a first synchronization signal to the forward left radar and the backward right radar at a timing associated with a start timing of radio wave transmission of the backward right radar;
each of the forward left radar and the backward right radar is configured to determine a start timing of radio wave transmission radar based on a reception timing of the first synchronization signal;
one of the forward left radar and the backward right radar is configured to send a second synchronization signal to the forward right radar and the backward left radar at a timing associated with a start timing of radio wave transmission of the one of the forward left radar and the backward right radar; and
each of the forward right radar and the backward left radar is configured to determine a start timing of radio wave transmission based on a reception timing of the second synchronization signal.
4. The vehicle surroundings monitoring apparatus according to claim 1 , wherein said processor is configured to:
control radio wave transmission of said forward right radar;
control radio wave transmission of said forward left radar;
control radio wave transmission of said backward right radar; and
control radio wave transmission of said backward left radar, and wherein,
the backward right radar is configured to: send a first synchronization signal to the forward left radar and the backward right radar at a timing associated with a start timing of radio wave transmission of the backward right radar;
each of the forward left radar and the backward right radar is configured to determine a start timing of radio wave transmission based on a reception timing of the first synchronization signal;
one of the forward left radar and the backward right radar is configured to send a second synchronization signal to the forward right radar and the backward left radar at a timing associated with a start timing of radio wave transmission of the one of the forward left radar and the backward right radar; and
each of the forward right radar and the backward left radar is configured to determine a the start timing of radio wave transmission based on a reception timing of the second synchronization signal.
5. The vehicle surroundings monitoring apparatus according to claim 1 , wherein the backward right radar is configured to: send a first synchronization signal to the forward left radar and the backward right radar at a timing associated with a start timing of radio wave transmission of the backward right radar.
6. The vehicle surroundings monitoring apparatus according to claim 1 , wherein one of the four radars of one of the groups is configured to: send a first synchronization signal to each of the radars of the other group at a timing associated with a start timing of radio wave transmission of the one of the four radars of the one of the groups.
7. The vehicle surroundings monitoring apparatus according to claim 1 , wherein each of the four radars is configured to delay a start timing of radio wave transmission based on receiving the synchronization information, and transmit the synchronization information for causing the delay to another radar that has an overlapping detection area.
8. A vehicle surroundings monitoring method comprising:
controlling, by a processor, a communication interface to transmit a radio wave transmission request to a first one of four radars, wherein the four radars include a forward right radar, a forward left radar, a backward right radar, and a backward left radar, each of the four radars performing object detection in a respective detection area around a vehicle by transmitting a radio wave and receiving a reflection wave generated as a result of reflection by a real object, the forward right radar being disposed at a front right corner part of a body of the vehicle, the forward left radar being disposed at a front left corner part of the body, the backward right radar being disposed at a rear right corner part of the body, and the backward left radar being disposed at a rear left corner part of the body; and
based on receiving a radio wave transmission request, performing, by at least one of the radars of each group of two radar groups, the following operations: (i) controlling timing of performance of a radar operation in accordance with a first transmission period, and (ii) send synchronization information regarding the first transmission period to at least one of the radars of a group of two groups that is different from the group of the two groups the sending radar belongs to, wherein
the four radars include two groups including a first diagonal radars group including the forward right radar and the backward left radar, and a second diagonal radars group including the forward left radar and the backward right radar, and
the radio wave transmission request includes the first transmission period for which each radar of the first diagonal radars group transmits the radio wave in a synchronized manner.
9. The vehicle surroundings monitoring method according to claim 8 , further comprising sending, by one of the four radars of one of the groups, a first synchronization signal to each of the radars of the other group at a timing associated with a start timing of radio wave transmission of the one of the four radars of the one of the groups.
10. The vehicle surroundings monitoring method according to claim 8 , further comprising: delaying, by one or more of the four radars, a start timing of radio wave transmission based on respective receiving of the synchronization information, and transmitting the synchronization information for causing the delay to another radar that has an overlapping detection area.