JPH0465323B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an azimuth calculation device for a moving object such as a vehicle or a ship.

Conventionally, this type of azimuth calculation device detects, for example, a temporal angular change in the traveling direction of a vehicle, that is, an angular velocity, using a gas rate sensor, and integrates the detection result of the gas rate sensor over time using an integrating circuit. Some systems use the integration result as a value corresponding to the traveling direction of the vehicle. However, in such a configuration, if the integration time is short, the integration result is a highly accurate value, but if the integration time is long, an error in the integration result based on the drift error inherent to the gas rate sensor increases. There is a problem that becomes large.

The present invention has been made in response to the above-mentioned problems, and its purpose is to accurately calculate the heading direction of a moving object without being affected by the above-mentioned drift error. The object of the present invention is to provide an azimuth calculation device.

In order to achieve such an object, the structural features of the present invention include a first detection means for detecting a temporal angular change in the moving direction of the moving body as a first azimuth angle, and a first detection means for detecting a temporal angular change in the moving direction of the moving body, and an angular difference between the moving direction of the moving body and the geomagnetic direction. the second
a second detection means for detecting as an azimuth angle; a pulse signal generation means for repeatedly generating a pulse signal over time; a first addition means for obtaining a first addition value corresponding to the traveling direction of the moving object; and the pulse signal generation means. calculating means for calculating the difference between the second azimuth angle and the first added value in response to a preceding pulse signal from the means, and multiplying the calculation result by a constant (<1);
A second addition means for calculating a second addition value and a latch means for latching the second addition value in response to a trailing pulse signal from the pulse signal generation means are provided, and the second addition means calculates the second addition value. The multiplication result by the means is added to the second latch addition value by the latch means, and the addition result is used as the second addition value, and the first addition means responds to the trailing pulse signal to calculate the first azimuth angle. The second latch addition value is added to the second latch addition value, and the addition result is used as the first addition value.

By configuring the present invention in this way, the first addition value is determined by the sum of the product of the initial value (1-α) ^m and the second azimuth angle, so that m is As the number of generated pulse signals increases, (1-α) ^m approaches zero, and as a result, the first added value becomes substantially equal to the second azimuth angle. This means that even if the error in the first azimuth angle based on the drift error inherent in the first detection means increases over time, the error in the second azimuth angle will not be affected by this. This means that the moving direction of the moving body can be specified.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings show a block circuit of a vehicle azimuth calculation device according to the present invention, and this azimuth calculation device includes an angular velocity sensor 10, a geomagnetic sensor 20,
An integrating circuit 30 and a conversion circuit 40 are connected to the angular velocity sensor 10 and the geomagnetic sensor 20, respectively.
It is equipped with The angular velocity sensor 10 is composed of a rate gyro, a gas rate sensor, etc., and detects a temporal angular change in the traveling direction of the vehicle, and generates the detection result as an angular velocity signal. The geomagnetic sensor 20 detects the difference in orientation of the vehicle's traveling direction with respect to due north (i.e., the direction of geomagnetism) as first and second coordinate components, and converts these first and second coordinate components into first and second coordinate components, respectively. It is generated as two azimuth component signals. Integrating circuit 30 responds to the angular velocity signal from angular velocity sensor 10, digitally integrates the value of this signal over time, and generates the integration result as a digital azimuth signal. The conversion circuit 40 digitally calculates the ratio of the values of these two signals in response to the first and second azimuth component signals from the geomagnetic sensor 20, and generates the calculation result as a digital azimuth signal.

Further, the azimuth calculation device includes a mileage sensor 50
A shaping circuit 60 connected to the mileage sensor 50, a latch circuit 70 connected to the integrating circuit 30 and the shaping circuit 60, and a latch circuit 80 connected to the conversion circuit 40 and the shaping circuit 60 are provided. The sensor 50 detects this for each unit mileage of the vehicle, and sequentially generates each detection result as a mileage signal α _o (n=1, 2, . . . ).
The shaping circuit 60 sequentially shapes the waveform of each mileage signal α _o from the mileage sensor 50 and generates a shaped signal b _o . The latch circuit 70 sequentially latches the digital azimuth signals from the integrating circuit 30 in response to each shaping signal _bo from the shaping circuit 60, and converts the value of each digital azimuth signal (hereinafter referred to as heading _o ) into a latched azimuth signal. occurs as. Latch circuit 80
latches the digital azimuth signals from the conversion circuit 40 in response to each shaping signal b _o from the shaping circuit 60, and generates the value of each digital signal (hereinafter referred to as heading azimuth D _o ) as a latched azimuth signal. do.

The azimuth calculation device also includes an adder 90 connected to the latch circuit 70 and the latch circuit 130, and a subtracter 100 connected to the latch circuit 80 and the adder 90.
And this subtracter 100 and constant setting circuit 110a
, and an adder 120 connected to the multiplier 110 _and the latch circuit 130. It is added to the value φ _o of the resulting latch addition signal, and the addition result (θ _o = _o + φ _o ) is generated as an output azimuth signal. The subtracter 100 subtracts the value θ o of the output azimuth signal from the adder 90 from the value D _o of the latch azimuth signal from the latch circuit ₈₀ , and obtains the result of this subtraction (D _o −θ _o =D _o − _o −φ _o ). is generated as a subtraction signal.

The constant setting circuit 110a generates a constant α as a setting signal, and the value α of this setting signal is determined by the convergence of the value _o of the latch azimuth signal to the value D _o of the latch azimuth signal in relation to the traveling distance of the vehicle. Represents degree. In this example, ₀ < _α
<1. The multiplier 110 multiplies the value of the subtraction signal (D _o −θ _o ) from the subtracter 100 by the value α of the setting signal from the constant setting circuit 110a, and generates this multiplication result α (D _o −θ _o ) as a multiplication signal. do. The adder 120 adds the value φ _o of the latch addition signal from the latch circuit 130 to the value α(D _o −θ _o ) of the multiplication signal from the multiplier 110, and the addition result {α(D _o
−θ _o )+φ _o } is generated as an addition signal. The latch circuit 130 latches the addition signal from the adder 120 in response to the shaping signal _bo from the shaping circuit 60, and the value of this addition signal {α(D _o-1 −θ _o-1 )+φ _{o- 1} }
=φ _o is generated as a latch addition signal, and
In response to the shaping signal b _o+1 from the shaping circuit 60, the addition signal subsequent to the addition signal from the adder 120 is latched, and the value of this addition signal {α(D _o −θ _o )+
φ _o }=φ _o+1 is generated as a latch addition signal following the latch addition signal.

By the way, when we consider mathematically the value φ _o of the latch addition signal from the latch circuit 130, we find that n=1,
2. If D _o = D, _o = in ..., φ _o = α (D−−φ _o-1 ) + φ _o-1 ...(1) Transform equation (1) as follows. For example, φ _o -(D- = α(D--φ _o-1 )-(D-) + φ _o-1 = (1-α) {φ _o-1 −(D-)} = (1-α) ² {φ _o-2 −(D−)} ...=(1−α) ^n-1 {φ ₁ −(D−)} ...(2) is obtained. Therefore, in this equation (2), ,0<α
Considering <1 and let n→∞, (1-α) ^n-1 →
0, so φ _o +=D ...(3) holds true. This means that as the number of shaping signals b _o generated from the shaping circuit 60 increases, the value θ _o = _o +φ _o = +φ _o of the output orientation signal of the adder 90 increases as the value D of the latch orientation signal from the latch circuit 80 increases. This means that _o = convergence to D.

In this embodiment configured as described above, when the vehicle is driven and the device of the present invention is activated, the integrating circuit 30 generates a digital azimuth signal in cooperation with the angular velocity sensor 10, and the converting circuit 4
0 generates a digital azimuth signal in cooperation with the geomagnetic sensor 20. At this stage, when the shaping circuit 60 generates a shaping signal b o-1 in response to the mileage signal a _{o-1 generated} from the mileage sensor 50, this shaping signal b _o-1 is transmitted to each latch circuit 70, 80,13
Assigned to 0. Then, the latch circuit 70 latches the digital azimuth signal from the integrating circuit 30 in response to the shaping signal b _o-1 and changes the value of this signal.
_o-1 is generated as a latch orientation signal and applied to adder 90.

Further, the latch circuit 80 latches the digital azimuth signal from the conversion circuit 40 in response to the shaping signal b _o-1 from the shaping circuit 60, and also latches the value of this signal.
D _o-1 is applied to the subtracter 100 as a latch azimuth signal, and at the same time, the latch circuit 130 latches the addition signal generated in advance from the adder 120, and the value of this addition signal φ _{o- 1} = {α
(D _o-2 −θ _o-2 )+φ _o-2 } is applied to both adders 90 and 120 as a latch addition signal. Then, the adder 90 receives the value of the latch direction signal from the latch circuit 70.
The value φ _o-1 of the latch addition signal from the latch circuit 130 is added to _o-1 , and the addition result (θ _o-1 =
_o-1 +φ _o-1 ) is generated as an output azimuth signal and applied to the subtracter 100.

Next, the subtracter 100 subtracts the value θ _o-1 of the output azimuth signal from the adder 90 from the value D _o-1 of the latch azimuth signal from the latch circuit 80, and the subtraction result (D _o-1 −θ _{o- 1} ) is generated as a subtraction signal, and the multiplier 110 multiplies the value α of the setting signal from the constant setting circuit 110a by the value (D _o-1 −θ _o-1 ) of the subtraction signal from the subtracter 100, and performs this multiplication. Result α(D _o-1 −
θ _o-1 ) is generated as a multiplication signal, and the adder 12
The value α(D _o-1 −θ _o-1 ) of the multiplication signal multiplied by 0 is added to the value φ _o-1 of the latch addition signal from the latch circuit 130, and the addition result {α(D _o-1 −θ _{o -1} ) +φ _o-1 } is generated as an addition signal.

After that, the shaping circuit 60 converts the mileage sensor 50
In response to the mileage signal a _o resulting from the shaping signal b _o
is generated, this shaped signal b _o is sent to each latch circuit 7.
Granted to 0,80,130. Then, the latch circuit 70 latches the digital azimuth signal from the integrating circuit 30 in response to the shaping signal b _o from the shaping circuit 60, and generates the value _o of this signal as a latch azimuth signal. 8
0 latches the digital azimuth signal from conversion circuit 40 and generates the value D _o of this signal as the latched azimuth signal. Further, the latch circuit 130 responds to the shaping signal b _o from the shaping circuit 60 and calculates the value of the addition signal from the adder 120 φ _o ={α(D _o-1 −θ _o-1 )
+φ _o-1 } is generated as a latch addition signal, and accordingly, the adder 90 adds the value φ _o of the latch addition signal from the latch circuit 130 to the value _o of the digital azimuth signal from the latch circuit 70, and the addition result is (θ _o =
_o +φ _o ) is generated as an output azimuth signal. As understood from the above mathematical study results, as n increases, the value of the output azimuth signal, that is, the value corresponding to the traveling azimuth of the vehicle, changes to the latch circuit 8.
This means that the value of the latch orientation signal from zero is close to and substantially equal to.

By the way, in the above explanation of the operation, when the vehicle is stopped at the same point for a long time due to traffic congestion, the distance signal from the distance sensor 50, that is, the shaping circuit 60 Since generation of the shaping signal stops due to stagnation of the vehicle, each latch circuit 70, 80, 13
The content of the latch 0 is held at the value immediately before the generation of the shaping signal from the shaping signal 60 stopped. Therefore, even if the magnetic field around the vehicle is disturbed while the vehicle is stagnant and an error due to the disturbance of the magnetic field due to the inherent shortcomings of the geomagnetic sensor 20 is mixed into the value of the digital azimuth signal from the conversion circuit 40, , regardless of this, the value of the output azimuth signal from the adder 90 is the value of each latch circuit 70, 8 immediately before the vehicle stops.
It is properly defined by the latch contents of 0.130. This also applies even if the time during which the magnetic field is disturbed becomes longer.

In addition, in implementing the present invention, latch circuits 70, 80, 130, adders 90, 120, subtracter 100, multiplier 110, and constant setting circuit 110
It goes without saying that a microcomputer programmed to perform the same functions as those described above may be used instead of a.

Further, in the above embodiment, an example in which the present invention is applied to a vehicle has been described, but instead of this,
For example, the present invention may also be applied to a moving body such as a ship.

Further, in the embodiment, the latch circuit 7
Although an example has been described in which the mileage sensor 50 and the shaping circuit 60 are used as means for updating the contents of the 0, 80, and 130 latches, instead of this, a clock circuit that generates a series of clock signals may be used as the updating means. It may also be carried out.

[Brief explanation of the drawing]

The drawing is a block circuit diagram showing one embodiment of the present invention. Explanation of symbols, 10...Angular velocity sensor, 20...
Geomagnetic sensor, 30... Integrating circuit, 40... Conversion circuit, 50... Mileage sensor, 90, 120...
... Adder, 100 ... Subtractor, 110 ... Multiplier, 110a ... Constant setting circuit, 130 ... Latch circuit.

Claims (1)

[Claims] 1. A first detection means for detecting a temporal angular change in the moving direction of the moving body as a first azimuth angle, and a second detecting means for detecting an angular difference between the moving direction of the moving body and the geomagnetic direction as a second azimuth angle; pulse signal generating means for repeatedly generating a pulse signal over time; first adding means for calculating a first addition value corresponding to the traveling direction of the moving body; a calculation means for calculating the difference between the second azimuth angle and the first addition value and multiplying the calculation result by a constant (<1); a second addition means for calculating the second addition value; and a pulse signal generation means. latching means for latching the second added value in response to a trailing pulse signal;
The second addition means adds the multiplication result by the calculation means to the second latch addition value by the latch means, and sets the addition result as the second addition value, and the first addition means adds the result of the multiplication by the calculation means to the second latch addition value by the latch means, and An azimuth calculation device for a moving object, which responsively adds the second latch addition value to the first azimuth angle and uses the addition result as the first addition value.