JPH0614912U - Azimuth detector - Google Patents

Abstract

(57) [Abstract] [Purpose] By simplifying the circuit configuration, the number of parts is greatly reduced, cost is reduced, size and size are reduced, and detection accuracy is increased. A pair of signals that separates a detection signal Sx of at least a detection coil 2x (same for 2y side) into a positive side component Sxp and a negative side component Sxn, and processes the signals. The signal processing system 4x includes circuits 5xp and 5xn and an integrating circuit 6x that integrates the positive side component Sxp and the separated negative side component Sxn. In particular, both of the signal circuits 5xp and 5xn are connected to one input portion 7a of the single operational amplifier 7, and the signal circuits 5xp and 5xn are connected to the integrating resistors 8p and 8n, respectively, and one of the operational amplifiers 7 is connected. Input unit 7a and output unit 7b
An integrating circuit 6x having an integrating capacitor 9 connected therebetween is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an azimuth detecting apparatus suitable for use in a navigation system mounted on a vehicle.

[0002]

[Prior art]

 Generally, in a car navigation system that uses direction information by radio waves from artificial satellites, mapping information of CD-ROM, etc., it is possible to easily input information such as the current driving position and driving guidance by inputting the destination in advance. I can know. However, in some navigation systems, stable position information cannot be obtained due to poor reception of radio waves, so such navigation systems usually detect the geomagnetic field and supplement unstable direction information. It is equipped with an azimuth detector.

Conventionally, this type of azimuth detecting device has an X-direction detection coil having an X-axis and a Y-axis having a Y-axis, with respect to a toroidal core having a Z-axis that is wound around an exciting coil. A fluxgate type (double frequency modulation type) magnetic sensor with a direction detection coil (see reference numeral 2 in Fig. 3) and the output value corresponding to the azimuth by processing the detection signal of each detection coil in this magnetic sensor. It was equipped with a signal processing system that obtains the following. In particular, the signal processing system was configured as shown in FIG.

Next, the configuration and operation of the signal processing system will be described with reference to FIGS. 4 and 5. In FIG. 4, reference numeral 51 denotes an X-direction detection coil in the magnetic sensor, which is detected by exciting the excitation coil (see reference numeral 2b in FIG. 3) with the pulse excitation signal Sb of 5 to 10 kHz shown in FIG. A detection signal Sx shown in FIG. 5B is obtained from the coil 51, and the detection signal Sx is given to a pair of signal circuits 53p and 53n connected in parallel via an amplifier circuit 52. If the analog switches 54p and 54n are connected to the signal circuits 53p and 53n, respectively, and one of the analog switches 54p is controlled by the opening / closing control signal Sp shown in FIG. If only the positive side component Sxp of the detection signal Sx shown in E) passes and the other analog switch 54n is controlled by the opening / closing control signal Sn shown in FIG. 5D, the signal circuit 53n will be shown in FIG. Only the negative side component Sxn of the detection signal Sx shown in FIG. Further, integrating circuits 55p and 55n are connected to the respective stages of the analog switches 54p and 54n in the signal circuits 53p and 53n, respectively, and the components Sxp and Sxn are integrated by the integrating circuits 55p and 55n. At this time, since each of the integrating circuits 55p and 55n is controlled by the set signal Ss and the reset signal Sr shown in FIG. 5G, the output of each of the integrating circuits 55p and 55n is repeated in units of several msec. H) and (I) are obtained as sawtooth-shaped integrated output signals Sop and Son, respectively. The inclination angle of the signal waveform in each integrated output signal Sop, Son changes according to the azimuth. Further, in each of the integrating circuits 55p and 55n, different constants are set so as to reduce the relative error between the components Sxp and Sxn. On the other hand, the integrated output signals S op and Son are added by the adder circuit 56 to obtain the output signal Som of FIG. 5 (J), and the maximum value of the output signal Som is obtained by the latch signal Sh shown in FIG. The instantaneous value in the vicinity is held by the hold circuit 57, and the output value corresponding to the position is obtained from the output circuit 58.

[0005]

[Problems to be solved by the device]

 However, the above-described conventional azimuth detecting device requires the two integrating circuits 55p and 55n corresponding to the positive side component Sxp and the negative side component Sxn of the detection signal Sx, and the adding circuit 56. As a result, the circuit configuration becomes complicated, the number of parts increases, and the cost and size of the device increase. In particular, when the device is built into the navigation system, the increase in size is one of the most important problems because the mounting space of the vehicle is limited.

The present invention solves the problems existing in such conventional techniques. By simplifying the circuit configuration, the number of parts can be greatly reduced, the cost can be reduced, and the size can be reduced. An object of the present invention is to provide an azimuth detecting device capable of increasing detection accuracy.

[0007]

[Means for Solving the Problems]

 In the present invention, an X-direction detection coil 2x having an X-axis axis and a Y-direction detection coil 2y having a Y-axis axis are arranged with respect to a toroidal core 2c having a Z-axis axis wound around an exciting coil 2b. Flux gate type magnetic sensor 2, an exciting circuit 3 for exciting the exciting coil 2b by a pulse exciting signal Sb, and a detection signal Sx of at least the detection coil 2x (same for the 2y side) and a positive side component Sxp and a negative side. Azimuth detection device 1 comprising a pair of signal circuits 5xp and 5xn for separating and processing the component Sxn and a signal processing system 4x having an integrating circuit 6x for integrating the separated positive-side component Sxp and negative-side component Sxn In particular, when both the signal circuits 5xp and 5xn are connected to one input section 7a of the single operational amplifier 7, the signal circuits 5xp and 5xn The integrating resistor respectively 8p, connect 8n, and characterized in that it comprises an integration circuit 6x connected integrating capacitor 9 between the input portion 7a and the output portion 7b of one of the operational amplifier 7.

[0008]

[Action]

 According to the azimuth detecting device 1 of the present invention, in the flux gate type magnetic sensor 2, the exciting coil 2b is excited by the pulse exciting signal Sb supplied from the exciting circuit 3, whereby the X direction detecting coil 2x (2y side). Also the same), a detection signal Sx whose magnitude changes according to the azimuth is obtained. The detection signal Sx is processed by the signal processing system 4x, and an output value corresponding to the azimuth is obtained from the signal processing system 4x.

In this case, the detection signal Sx obtained from the detection coil 2x is separated into a positive side component Sxp and a negative side component Sxn by a pair of signal circuits 5xp and 5xn, and is separated into a single signal through different integrating resistors 8p and 8n. Is applied to one input portion 7a of the operational amplifier 7. As a result, the output of the integrator circuit 6x obtains an integrated output signal obtained by integrating the signal obtained by combining the positive-side component Sxp and the negative-side component Sxn. Since it is the same as the integrated output signal obtained by adding the signals integrated in the above, the integrating circuit is halved compared to the conventional one, and the adding circuit becomes unnecessary. In addition, detection accuracy can be improved by simplifying the circuit.

[0010]

【Example】

 Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, in order to clarify the present invention, an overall schematic configuration of the azimuth detecting apparatus 1 will be described with reference to FIG.

In FIG. 3, reference numeral 2 denotes a flux gate type (double frequency modulation type) magnetic sensor, which includes a toroidal core 2c around which an exciting coil 2b is wound, an X direction detecting coil 2x and a Y direction detecting coil 2y. The X-direction detection coil 2x and the Y-direction detection coil 2y are each wound in a ring shape and are arranged in a right-angled relationship with their centers being aligned with each other, and the axis of the X-direction detection coil 2x is in the X-direction and in the Y-direction. The axes of the detection coils 2y are relatively arranged so as to be in the Y direction. Furthermore, the toroidal core 2c is arranged inside the X-direction detection coil 2x and the Y-direction detection coil 2y so that their centers coincide with each other and their axes are relatively arranged in the Z direction. Therefore, the magnetic sensor 2 is displaced in the direction of arrow A so as to face north, south, east, and west in FIG. The direction of geomagnetism is indicated by arrow F.

On the other hand, 3 is an exciting circuit, which has a function of exciting the exciting coil 2b by supplying the pulse exciting signal Sb to the exciting coil 2b.

On the other hand, 4x and 4y are two signal processing systems, and the detection signals Sx and Sy from the detection coils 2x and 2y are supplied to their input sides, respectively. The output sides of the signal processing systems 4x and 4y are connected to the azimuth calculation unit 15. The azimuth calculation unit 15 obtains the final azimuth information Do from the output values corresponding to the azimuths obtained by the respective signal processing systems 4x and 4y, and gives the final azimuth information Do to, for example, a display unit, a data processing unit, or the like (not shown).

Next, the configuration of the signal processing system that constitutes the main part of the azimuth detecting apparatus 1 according to the present invention will be specifically described with reference to FIG. Since the two systems of signal processing systems 4x and 4y have the same basic configuration, only one signal processing system 4x will be described below.

In FIG. 1, reference numeral 2x indicates an X-direction detection coil for detecting the north-south direction, and the detection coil 2x is connected to the input side of the amplifier circuit 21. The output side of the amplifier circuit 21 is connected to the input side of an integrating circuit 6x having a pair of signal circuits 5xp and 5xn connected in parallel. That is, each signal circuit 5xp, 5xn is provided with integrating resistors 8p, 8n, one end of each integrating resistor 8p, 8n is connected to the output side of the amplifier circuit 21, and the other end of each integrating resistor 8p, 8n is respectively connected. Connect to one end of the analog switches 22p and 22n. The integrating resistors 8p and 8n may be fixed resistors whose resistance values are selected in advance, but it is desirable to use variable resistors so that the resistance values can be arbitrarily changed. In this case, gain can be set in each signal circuit 5xp, 5xn by changing each resistance value in each integration resistor 8p, 8n, and the relative error of the signal component flowing in each signal circuit 5xp, 5xn can be calculated. It can be reduced. Further, in FIG. 1, Sp and Sn represent open / close control signals for controlling the analog switches 22p and 22n.

On the other hand, the other end of each of the analog switches 22p and 22n is connected to the inverse input section 7a of the operational amplifier 7, and the integrating capacitor 9 is connected between the inverting input section 7a and the output section 7c of the operational amplifier 7. The non-inverting input section 7b of the operational amplifier 7 is grounded. On the other hand, the output section 7c of the operational amplifier 7, which is the output section of the integrating circuit 6x, is connected to the input side of the hold circuit 23, and the output side of the hold circuit 23 is connected to the input side of the output circuit 24. Then, the output side of the output circuit 24 is connected to the azimuth calculation unit 15 described above.

Next, the operation of the azimuth detecting apparatus 1 including the signal processing system 4x will be described with reference to FIGS.

First, the exciting coil 2b is excited by the pulse exciting signal Sb of 5 to 10 kHz shown in FIG. 2 (A).

On the other hand, if it is assumed that the X-direction detection coil 2x detects the north-south direction, the X-direction detection coil 2x outputs the normal direction shown in FIG. 2B according to the direction (direction) of the X-direction detection coil 2x. A detection signal Sx including the side component Sxp and the negative side component Sxn is obtained. The detection signal Sx is applied to the amplifier circuit 21, amplified, and then applied to the integration resistors 8p and 8n in the pair of signal circuits 5xp and 5xn.

Since the analog switch 22p in the one signal circuit 5xp is controlled by the opening / closing control signal Sp shown in FIG. 2C, only the positive side component Sxp of the detection signal Sx shown in FIG. Since the analog switch 22n in the other signal circuit 5xn is controlled by the open / close control signal Sn shown in FIG. 2D while being applied to the inverting input section 7a of the operational amplifier 7 through the signal circuit 5xp, Only the negative side component Sxn of the detection signal Sx shown in B) passes through the signal circuit 5xn and is applied to the inverting input section 7a of the operational amplifier 7. Therefore, each of the components Sxp and Sxn becomes an alternating signal synthesized in the inverting input section 7a and is integrated by the integrating circuit 6x.

In this case, since the integrator circuit 6x is controlled by the reset signals Ss and Sr shown in FIG. 2E, the output of the integrator circuit 6x is repeated in a cycle of several msec as shown in FIG. 2F. The sawtooth-shaped integrated output signal Sm is obtained. The inclination angle of the signal waveform in the integrated output signal Sm changes according to the azimuth.

The integrated output signal Sm is held by the latch circuit Sh shown in FIG. 2 (G) at an instantaneous value near the maximum value in the integrated output signal Sm, which is held in the hold circuit 23 and output to the outside via the output circuit 24. To do. The output value from the output circuit 24 corresponds to the azimuth.

On the other hand, the Y-direction detection coil 2y detects the azimuth in the east-west direction, and the signal processing system 4y functions (operates) similarly to the above-described signal processing system 4x.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments, and detailed circuit configurations and the like can be arbitrarily changed without departing from the gist of the present invention.

[0026]

[Effect of device]

 As described above, according to the present invention, the X-direction detection coil having the X-direction axis and the Y-direction detection coil having the Y-direction axis are arranged with respect to the toroidal core having the Z-direction axis wound around the exciting coil. Fluxgate magnetic sensor, an excitation circuit that excites the excitation coil with a pulse excitation signal, and a pair of signal circuits that separates the detection signals of at least each detection coil into a positive-side component and a negative-side component and performs signal processing. In a direction detection device having a signal processing system having an integrating circuit for integrating the separated positive side component and negative side component, both signal circuits are connected to one input section of a single operational amplifier, and Since an integrating resistor is connected to each signal circuit and an integrating capacitor is connected between one input part and the output part of the operational amplifier, the circuit configuration can be simplified. The remarkable effect that the number of parts can be greatly reduced, especially the integration circuit can be halved and the adder circuit can be eliminated, the cost of the entire device can be reduced and the size and size can be reduced, and the detection accuracy can be improved. Play.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a signal processing system of an azimuth detecting device according to the present invention,

FIG. 2 is a time chart of signals in each part of the signal processing system,

FIG. 3 is an overall schematic configuration diagram of the same direction detection device,

FIG. 4 is a block circuit diagram of a signal processing system of the azimuth detecting device according to the related art;

FIG. 5 is a time chart of signals in each part of the signal processing system,

[Explanation of symbols]

 1 azimuth detecting device 2 fluxgate type magnetic sensor 2b excitation coil 2c toroidal core 2x X direction detection coil 2y Y direction detection coil 3 excitation circuit 4x signal processing system 5xp signal circuit 5xn signal circuit 6x integration circuit 7 operational amplifier 7a One input of operational amplifier Part 7c Output of operational amplifier 8p Integral resistance 8n Integral resistance 9 Integral capacitor Sb Pulse excitation signal Sx Detection signal Sxp Positive side component Sxn Negative side component

Claims (1)

[Scope of utility model registration request] 1. An X-direction detection coil having an X-axis axis and a Y-direction detection coil having a Y-axis axis are arranged with respect to a toroidal core having an Z-axis axis wound around an exciting coil. Fluxgate type magnetic sensor, an exciting circuit for exciting the exciting coil by a pulse exciting signal, a pair of signal circuits for separating the detection signal of at least each detecting coil into a positive side component and a negative side component, and performing signal processing. In an azimuth detecting device comprising a signal processing system having an integrating circuit for integrating a positive side component and a negative side component, both signal circuits are connected to one input section of a single operational amplifier and An azimuth detecting device comprising an integrating circuit, each of which is connected to an integrating resistor, and an integrating capacitor is connected between one input portion and one output portion of an operational amplifier.