US 4,543,577 AGranted

Moving obstacle detection system for a vehicle

AssigneeNissan Motor Co., Ltd.

InventorsAkira Tachibana, Norio Fujiki, Hiroshi Endo, Kiyoshi Yamaki, Norimasa Kishi

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Abstract

A moving obstacle detection system for an automotive vehicle utilizing a doppler effect of the transmitted wave against an obstacle which runs in front of the vehicle such as another vehicle. The system generally comprises: (a) a doppler radar unit which operates so as to produce a doppler signal when the vehicle is halted; (b) a detecting means which detects the changing phase of a doppler signal produced from the doppler signal; (c) a discriminating means which discriminates the departure of another vehicle from the front area of the vehicle and the intersection of another vehicle or pedestrian traverse to the vehicle on a basis of the frequency changing rate or amplitude level changing rate of the detected doppler signal; and (d) an alarm unit which produces an alarm in a predetermined form only when the departure of another vehicle from the front detection area of the doppler radar unit or in the case when another vehicle straightly approaches or departed from the vehicle and in the case when another vehicle or pedestrian goes across the vehicle, separately from each other.

Claims21

Dependent claims

A moving obstacle detection system for an automotive vehicle, which comprises:

(a) a doppler radar unit which operatively transmits a wave having a fixed frequency toward a forward direction of the vehicle when the vehicle halts, receives the reflected wave from a moving obstacle in front of the vehicle, and outputs a doppler signal having a frequency corresponding to the frequency difference between the transmitted and reflected waves and an amplitude which changes according to the distance between the vehicle and moving obstacle;
(b) a first means responsive to the doppler signal from said doppler radar unit for determining whether the frequency of the doppler signal exceeds a first predetermined value so as to detect the approach or departure of a moving obstacle toward or away from the vehicle;
(c) a second means responsive to the doppler signal for determining whether the duration of the amplitude level of the doppler signal which exceeds a second predetermined value exceeds a predetermined interval of time so as to distinguish the approach or departure of the moving obstacle toward or away from the vehicle from the movement of an obstacle transverse to the vehicle direction;
and
(d) an alarm unit which produces an alarm in a predetermined form when said first means determines that the frequency of the doppler signal exceeds the first predetermined value and said second means determine that the duration exceeds the predetermined interval of time,
whereby said alarm unit produces the alarm only when another vehicle approaches toward the forward direction of the vehicle or departs away from the vehicle.

3 more elements

A moving obstacle detection system for an automotive vehicle, which comprises:

(a) a doppler radar unit which transmits a wave having a fixed frequency toward a forward direction of the vehicle when the vehicle is halted, receives the reflected wave from a moving obstacle, and amplifies and outputs a doppler signal having a frequency corresponding to the frequency difference between the transmitted and reflected waves and an amplitude which changes according to the distance between the vehicle and moving obstacle;
(b) a first means which receives the doppler signal from said doppler radar unit for determining whether the frequency of the doppler signal exceeds a first predetermined value so as to detect the approach or departure of an obstacle toward or from the vehicle;
(c) an interval of time setting means which, responsive to the doppler signal from said doppler radar unit, outputs a voltage signal having a first predetermined duration when the amplitude of the doppler exceeds a predetermined threshold value for discriminating the approach or departure from the vehicle and the traversed intersection of a moving obstacle;
(d) a vehicle halt detector which detects the halt state of the vehicle and outputs a voltage signal indicating the vehicle is halted;
and
(e) an alarm unit which produces the alarm in a predetermined form to indicate the vehicle driver that an obstacle is approaching or departing from the vehicle when said first means determines that the frequency of the doppler signal exceeds the first predetermined value during the receipt of the voltage signal from said interval of time setting means, and said vehicle halt detector outputs the voltage signal thereinto.

3 more elements

A moving obstacle detection system for an automotive vehicle, which comprises:

(a) a doppler radar unit which transmits a wave having a fixed frequency toward a forward direction of the vehicle, receives reflected waves reflected from a moving obstacle, and outputs a doppler signal having a frequency corresponding to a frequency difference between the transmitted and reflected waves and an amplitude whch changes according to the distance between the vehicle and moving obstacle when the vehicle is halted;
(b) a first means, responsive to the doppler signal from said doppler radar unit for determining whether the frequency of the doppler signal exceeds a first predetermined value so as to detect the approach or departure of a moving obstacle toward or from the vehicle;
(c) a second means, responsive to the doppler signal from said doppler radar unit for determining whether a frequency changing rate or amplitude level changing rate of the dopler signal exceeds a second predetermined value so as to detect approach or departure of a moving obstacle toward or from the vehicle;
(d) a third means which, responsive to said doppler signal, outputs a voltage signal when an interval of time predetermined therein exceeds an interval of time during which the doppler signal appears for a single moving obstacle so as to detect an intersection of another vehicle transverse to the vehicle;
(e) a vehicle halt detector which detects the halted state of the vehicle and outputs a voltage signal indicating that the vehicle is halted;
(f) a first alarm unit which produces an alarm urgently in a predetermined form when the voltage signal from said third means is received or when said first means determines that the frequency of the doppler signal exceeds the first predetermined value, with the output voltage signal from said vehicle halt detector received and with said second means determining that neither the frequency changing rate nor the amplitude level changing rate exceed the second predetermined value;
(g) a second alarm unit which produces an alarm in another predetermined form when said first means determines that the frequency of the doppler signal exceeds the first predetermined value with the output voltage signal from said vehicle halt detector received and with said second means determining that either the frequency changing rate or the amplitude level changing rate exceeds the second predetermined value;
and
(h) a doppler radar unit switching unit which temporarily halts the transmission of the wave from said doppler radar unit when said vehicle halt detector outputs no voltage signal.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/388,704Filed 15 Jun 1982
Priority: JP 56-9634922 Jun 1981
Granted: 24 Sep 1985
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01S 13/536
Discriminating between fixed and moving objects or between objects moving at different speeds: using transmission of continuous unmodulated waves,…
G01S 13/56
Discriminating between fixed and moving objects or between objects moving at different speeds: for presence detection
G01S 13/931
For anti-collision purposes: of land vehicles
G01S 13/52
Systems of measurement based on relative movement of target: discriminating between fixed and moving objects or between objects moving at…