Radar device

• US 9,322,905 B2
• Filed: 03/12/2013
• Issued: 04/26/2016
• Est. Priority Date: 03/19/2012
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kishigami, Takaaki, Tokuhiro, Takafumi, Morita, Tadashi
• Primary Examiner(s): Sotomayor, John B
• Application Number:
  US14/118,087
• Publication Number:
  US 20140085127A1
• Time in Patent Office: 1,141 Days
• Field of Search: 342/108, 342/107, 342/90, 342/189, 342/195, 340/928, 340/933
• US Class Current: 1/1
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/284 using coded pulses
• CPC Class Codes: G01S 13/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 13/581 using transmission of interrupted pulse modulated waves and based upon the Doppler effect resulting from movement of targets
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G01S 13/92 for velocity measurement
• CPC Class Codes: G01S 7/4091 during normal radar operation
• CPC Class Codes: G01S 7/41 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G08G 1/015 with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
• CPC Class Codes: G08G 1/052 with provision for determining speed or overspeed speed measuring in general G01P

Abstract

A radar transmitting unit Tx transmits a radio-frequency radar transmission signal from a transmission antenna which is inclined in the direction of a depression angle φ. A radar receiving unit Rx estimates the height and speed of a vehicle which travels on a road surface using a reflected wave signal from the vehicle. A template generating unit generates a variation in a phase component of the reflected wave signal corresponding to N heights and speeds of the vehicle as N templates. N vehicle height/speed template correlation calculation units #1 to #Nrep calculate correlation on the basis of any one of the N templates and a correlation value between the reflected wave signal and a transmission code of the radar transmission signal.

Claims

1. A radar device configured to be installed at a position which is at a predetermined height from a road surface, comprising:

a radar transmitting unit configured to transmit a radio-frequency radar transmission signal from the position which is at the predetermined height to the road surface from a transmission antenna which is inclined in a direction of a predetermined depression angle; and

a radar receiving unit configured to estimate a position parameter and a speed of a vehicle which travels on the road surface, using a reflected wave signal which is the radar transmission signal reflected from the vehicle which travels on the road surface,

wherein the radar receiving unit includes;

a correlation calculation unit configured to calculate correlation on the basis of the reflected wave signal and a transmission code of the radar transmission signal;

a template generating unit configured to generate a variation in a phase component of the reflected wave signal corresponding to N position parameters and speeds of the vehicle as N templates;

N template correlation calculation units configured to calculate correlation on the basis of any one of the generated N templates and a correlation value between the reflected wave signal and the transmission code of the radar transmission signal; and

an output selection unit configured to determine a type of the vehicle, using the position parameter and the speed of the vehicle corresponding to any one of the generated N templates, on the basis of outputs from the N template correlation calculation units.

2. The radar device according to claim 1,

wherein the position parameter is a height of the vehicle or a distance between the radar device and the vehicle.

3. The radar device according to claim 1,

wherein the radar receiving unit further includes an adder unit configured to add the correlation value between the reflected wave signal and the transmission code of the radar transmission signal a predetermined number of times, and

each of the template correlation calculation units is configured to calculate the correlation on the basis of an output of the adder unit and any one of the generated N templates.

4. The radar device according to claim 1,

wherein, where there are a plurality of outputs greater than a predetermined threshold value among the outputs of the N template correlation calculation units, the output selection unit is configured to select a maximum value of the outputs greater than the predetermined threshold value as an estimated value.

5. The radar device according to claim 1,

wherein, where there are a plurality of outputs greater than a predetermined threshold value among the outputs of the N template correlation calculation units, the output selection unit is configured to perform an interpolation process using the plurality of outputs greater than the predetermined threshold value and select an output after the interpolation process as an estimated value.

6. The radar device according to claim 1,

wherein each template generating unit is configured to generate a variation in a real component of the phase component in the reflected wave signal corresponding to the N position parameters and speeds of the vehicle as the N templates.

7. The radar device according to claim 6,

wherein each template generating unit is configured to generate a variation in an imaginary component of the phase component in the reflected wave signal corresponding to the N position parameters and speeds of the vehicle as the N templates.

8. The radar device according to claim 3,

wherein each template correlation calculation unit includes:

a down sampling unit configured to down-sample the output of the adder unit at a predetermined interval; and

a correlation calculation unit configured to calculate correlation on the basis of the down-sampled output of the adder unit and any one of the generated N templates.

9. The radar device according to claim 3,

wherein the direction of the predetermined depression angle is a direction in which a path of the radar transmission signal between the radar device and the vehicle which travels immediately below the radar device is included in a range of a beam width of the radar transmission signal, and

the template generating unit is configured to generate Np (<

N) templates corresponding to the position parameter and the speed of the vehicle, using the position parameter of the vehicle when the path of the radar transmission signal is included in a range bin at each sampling time.

10. The radar device according to claim 9,

wherein the radar receiving unit further includes a distance selection output unit configured to output the output of the adder unit to the Np (<

N) template correlation calculation units according to the generated Np templates.

11. The radar device according to claim 3,

wherein the radar receiving unit further includes a road surface reflected wave signal detecting unit configured to detect a road surface reflected wave signal from the road surface on the basis of the output of the adder unit and detects a time when the vehicle starts to pass through a detection area corresponding to the range of a beam width of the radar transmission signal, and

each template correlation calculation unit is configured to calculate the correlation on the basis of each output of the adder unit after a detection time of the road surface reflected wave signal.

12. The radar device according to claim 3,

wherein the radar receiving unit further includes a road surface reflected wave signal detecting unit configured to detect a road surface reflected wave signal from the road surface on the basis of the output of the adder unit and detect a time when the vehicle starts to pass through a detection area corresponding to the range of the beam width of the radar transmission signal and a time when a passage of the vehicle through the detection area ends, and

the output selection unit is configured to select, as an estimated value, the speed of the vehicle corresponding to any one of the generated N templates on the basis of the outputs of the N template correlation calculation units and estimate a length of the vehicle on the basis of the passage start time and the passage end time.

13. The radar device according to claim 1,

wherein the position which is at the predetermined height from the road surface is a pole above a vehicle travel lane or a post on a side of the road.