JPH04291183A - Antenna tracking apparatus - Google Patents

Abstract

PURPOSE:To issue a radiowave shield alarm quickly. CONSTITUTION:In an apparatus for tracking a satellite by an antenna 10, a radiowave shield alarm computation circuit 30 and a radiowave shield alarm means 32 are provided. The radiowave shield alarm computation circuit 30 generates a radiowave shield alarm signal when a carrier detection signal CD can not be obtained although the antenna 10 is located within an azimuth range possible to catch the satellite, and makes the radiowave shield alarm means 32 operate. Thereby an alarm is issued without turning the antenna 10 all round and quick alarming is ensured.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna tracking device that is mounted on a moving object such as a vehicle or a ship and that tracks and receives satellites.

0002

2. Description of the Related Art Antenna tracking devices are known for use in receiving satellite broadcasts on trains and for maritime satellite communications. That is, in a moving object, the direction of the satellite (relative azimuth of the satellite) as seen from the main body of the moving object changes due to its movement. Therefore, in order to receive signals from a satellite and supply them to a satellite communication/satellite broadcasting receiver mounted on a mobile object, it is necessary to offset changes in orientation due to movement of the mounted mobile object by controlling the orientation of the antenna. There is. An antenna tracking device is an antenna device that enables such operations.

As mentioned above, the main uses of antenna tracking devices are satellite broadcast reception on trains and maritime satellite communications. In the former, the tracking signal is generally of the monopulse type. In this method, a sum-difference signal for tracking is generated and the antenna is driven using this sum-difference signal. Therefore, the tracking performance is said to be relatively good. The latter method uses a device that generates an azimuth reference, such as a gyro compass, and uses its output to cancel out changes in the relative satellite orientation caused by changes in the ship's course or turns.

On the other hand, when actually using the antenna tracking device, radio waves may be temporarily blocked by surrounding obstacles such as mountains, buildings, and standing trees. That is, a problem arises in that the antenna cannot capture the radio waves from the satellite, and the antenna wanders astray.

[0005] In the conventional antenna tracking device, such a phenomenon is detected by the entire circumference of the antenna, and a predetermined warning is issued to the occupants of the vehicle or the like.

[0006]

[Problems to be Solved by the Invention] However, in this configuration in which the antenna rotates all the way around, it takes time for the antenna to rotate around before issuing an alarm. In such a case, if a warning cannot be issued quickly, it will give the crew unnecessary anxiety such as whether the equipment is malfunctioning or if the equipment is connected to a telephone system. This may give rise to unnecessary anxiety, such as whether the person on the other end of the conversation has suddenly terminated the telephone conversation. Therefore, this will have a negative psychological impact on the occupants. The present invention has been made with the aim of solving these problems, and it is an object of the present invention to provide an antenna device that can more quickly issue a warning to a passenger without having to make the antenna go around the entire circumference. purpose.

[0007]

[Means for Solving the Problems] In order to achieve such an object, claim 1 of the present invention provides an antenna that is rotatably mounted on a moving body around an azimuth axis and has a predetermined directivity;
An angle detection means for detecting the antenna azimuth Av with reference to the moving object, a drive control means for driving the antenna so that the detected antenna azimuth Av matches a control target value, and an absolute azimuth Sn of the satellite and the moving object azimuth V. an azimuth axis calculation means for calculating a control target value of the antenna azimuth Av based on the antenna orientation Av, and an antenna tracking device that tracks a satellite while compensating for movement and turning of a moving object, wherein the antenna suitably captures the satellite. a carrier detection means that detects this and generates and outputs a carrier detection signal; a tracking error e is obtained by subtracting the sum of the mobile object direction V and the antenna direction Av from the satellite's absolute direction Sn;
Determine whether the tracking error e is within a predetermined range,
A radio wave shielding alarm calculation circuit that generates a radio wave shielding alarm signal when the carrier detection signal is within a predetermined range and no carrier detection signal is generated, and a radio wave shielding alarm means that issues a predetermined alarm in response to the radio wave shielding alarm signal. , the system is characterized by providing a warning when the antenna is blocked from the satellite by an obstacle.

[0008] A second aspect of the present invention also provides an antenna that is rotatably mounted on a movable body around an azimuth axis and has a predetermined directivity, and an angle detection means for detecting the antenna azimuth Av with respect to the movable body. a drive control means for driving the antenna so that the detected antenna azimuth Av matches a control target value; and a carrier detection means for detecting that the antenna is suitably capturing a satellite and generating and outputting a carrier detection signal. ,
An antenna azimuth search control circuit that rotates the antenna by gradually changing the control target value of the antenna azimuth Av until a carrier detection signal is obtained at least when initially acquiring a satellite; and a mobile azimuth that detects a change dV in the azimuth of the mobile object. detecting means and detecting the antenna orientation Av according to the change dV in the mobile object orientation.
an azimuth axis calculation means for sequentially changing and setting a control target value of an antenna tracking device for tracking a satellite while compensating for movement and turning of a moving object, the movement of which occurs at least when a carrier detection signal is obtained; Using the body orientation V0 as a reference, calculate the estimated value of the average value of the antenna orientation for a certain period after that point, consider it as the estimated value of the satellite orientation <Sv0>, and calculate the estimated value of the satellite orientation <Sv0> and the current mobile orientation V. The tracking error <e> is determined as the difference between the reference antenna orientations Av, and it is determined whether the tracking error <e> is within a predetermined range. If the tracking error <e> is within a predetermined range and no carrier detection signal is generated. a radio wave shielding alarm calculation circuit that generates a radio wave shielding alarm signal, and a radio wave shielding alarm means that issues a predetermined alarm in response to the radio wave shielding alarm signal, and provides an alarm when the antenna is shielded from the satellite by an obstacle, etc. It is characterized by

[0009]Furthermore, claim 3 provides that in claim 1,
The antenna is rotatable around an elevation axis, and includes an elevation angle detection means for detecting an antenna elevation angle, and a satellite elevation angle input means for inputting a satellite elevation angle, and the drive control means is arranged such that the antenna elevation angle matches the satellite elevation angle. drive the antenna so that the radio wave shielding alarm calculation circuit determines whether the difference between the antenna elevation angle and the satellite elevation angle is within a predetermined range, and generates a radio wave shielding alarm signal only when the difference between the antenna elevation angle and the satellite elevation angle is within the predetermined range. It is characterized by

[0010] And, claim 4 is, in claim 2,
The antenna is rotatable around an elevation axis, and includes an elevation angle detection means for detecting an antenna elevation angle, a drive control means drives the antenna so that the antenna elevation angle coincides with a satellite elevation angle, and a radio wave shielding alarm calculation circuit is provided. , estimate the average value of the antenna elevation angle during at least a period in which the carrier detection signal is obtained as the current satellite elevation angle, and determine whether the difference between the current antenna elevation angle and the estimated satellite elevation angle is within a predetermined range. However, it is characterized in that it generates a radio wave shielding alarm signal only when it is within a predetermined range.

[0011]

[Operation] In claim 1 of the present invention, the antenna direction A
A control loop relating to v is constructed, and the antenna orientation Av is controlled based on the absolute orientation Sn of the satellite and the mobile orientation V. That is, the antenna azimuth Av is detected by the angle detection means, and the antenna is adjusted around the azimuth axis by the drive control means so that the antenna azimuth Av matches the control target value determined based on the satellite absolute azimuth An and the mobile object azimuth V. driven by. The absolute azimuth Sn of the satellite is, for example, the azimuth of the satellite expressed with reference to the meridian, and the mobile object azimuth V is also the azimuth of the mobile object based on the same reference. Therefore, the relative orientation of the satellite is usually obtained by finding the difference Sn-V between the absolute orientation Sn of the satellite and the mobile orientation V.
If the antenna is rotated using this control target value, the antenna will always capture the satellite. As a result, the satellite will be tracked regardless of its movement or rotation.

[0012] Furthermore, in claim 1, when the radio waves arriving from the satellite are blocked by an obstacle such as a building,
For example, a warning is given to the occupants of the moving body. This warning is issued as follows. First, the carrier detection means detects whether or not the antenna is properly capturing the satellite. Here, carrier detection is the most common means for obtaining information regarding whether or not a desired signal is being received at a certain level, and is a conventionally known method. In the present invention, using such means, it is determined whether or not the above-mentioned shielding situation exists.

Furthermore, the radio wave shielding alarm calculation circuit calculates and determines the tracking error e. The tracking error e is a value determined by the following formula.

e=Sn-V-Av As mentioned above, when the antenna ideally captures the satellite, Sn-V matches Av. Therefore,
e expressed by the above equation becomes information representing a tracking error. In the radio wave shielding alarm calculation circuit, this tracking error e
It is determined whether or not the value is within a predetermined range. This determination corresponds to determining whether the antenna is facing in a direction in which it can be expected to capture a satellite. Therefore, if the tracking error e is within a predetermined range, it is recognized that the antenna can be expected to sufficiently capture the satellite. At this time, if the carrier detection signal is not being generated, that is, if the antenna is not properly capturing the satellite, it is considered that radio waves are being blocked by some kind of obstacle. In the radio wave shielding alarm circuit arithmetic circuit, a radio wave shielding alarm signal is generated in such a case and is supplied to the radio wave shielding alarm means. The radio wave shielding alarm means issues a predetermined alarm in response to this signal.

[0015] Therefore, in claim 1, radio wave shielding is detected without making a complete circuit of the antenna, and a corresponding alarm is issued, thereby ensuring prompt alarm.

Furthermore, in claim 2, unlike claim 1, the information related to input is a change in relative orientation dV. That is, the absolute orientation Sn of the satellite in claim 1 is, for example, G
The relative bearing V is obtained from a navigation device such as a PS, and a bearing sensor such as an FGC. This claim 2
discloses a configuration in which a radio wave shielding alarm is issued based on the same concept as claim 1, when such a device is not used and an inexpensive moving object direction detection means such as a rate sensor is used.

That is, in claim 2, the radio wave shielding alarm calculation circuit generates the radio wave shielding alarm signal by the following operation. First, the radio wave shielding warning calculation circuit calculates an estimate of the average value of the antenna orientation for a certain period after that point, using the mobile object orientation V0 at least at the time when the carrier detection signal is obtained as a reference, and estimates the satellite orientation. value<S
v0>. This estimated value <Sv0> is the direction in which the satellite is expected to exist based on the results of the movement of the mobile object up to that point. Therefore, by subtracting the antenna orientation Av based on the current mobile object orientation V from this estimated value <Sv0>, the tracking error <e> can be obtained. The reason why "<>" is added here, unlike the tracking error e in claim 1, is that this amount does not represent the actual tracking error but represents the estimated value of the tracking error. The radio wave shielding alarm calculation circuit determines whether or not this tracking error <e> is within a predetermined range, and if it is within the predetermined range and no carrier detection signal is generated, it is deemed that radio wave shielding has occurred. Generate radio shielding alarm signal. In addition, as an estimate of the average value of the antenna orientation, which is considered as the estimated value of the satellite orientation <Sv0>, it is possible to use ■the least squares estimate by the least squares method■the moving average value by the moving average method■the simple average value, etc. can.

[0018] Regarding the method of finding these average values,
It is known in the fields of mathematical statistics, time series analysis, etc. (for example,
(See Mitsuaki Fujii, “Time Series Analysis,” Chapter 6, Corona Publishing, etc.)

As described above, according to claim 2, radio wave shielding is detected without making the antenna go around the entire circumference in the antenna tracking device using a moving object direction detecting means such as a rate sensor, and prompt warning is ensured. .

Furthermore, in a third aspect of the present invention, the antenna tracking device according to the first aspect is further provided with a function of controlling the elevation angle direction of the antenna. That is, an antenna that can be rotated around an elevation axis in addition to an azimuth axis is employed as an antenna, and the drive control means is configured to rotate according to the antenna elevation angle detected by the elevation angle detection means and the satellite elevation angle based on information input from the outside. drives and controls the elevation angle of the antenna.

Furthermore, in claim 3, in view of the fact that the antenna is rotatable in two axes,
It is also determined whether the difference between the antenna elevation angle and the satellite elevation angle is within a predetermined range, and a radio wave shielding alarm signal is generated only when the difference is within a predetermined range.

Thus, in claim 3, the antenna tracking device that tracks the satellite based on the absolute azimuth Sn of the satellite and the azimuth V of the mobile object and controls the antenna in two axes also has the same rapid speed as in claim 1. appropriate warnings will be ensured.

[0023] In claim 4, a configuration is disclosed in which an apparatus using an antenna rotatable in two axes is used to control the orientation of the antenna related to the mobile object orientation detection means similar to claim 2. has been done. In this claim:
The radio wave shielding warning calculation circuit estimates the average value of the antenna elevation angle during at least the period during which the carrier detection signal is obtained as the current satellite elevation angle. It is determined whether the difference between the satellite elevation angle estimated in this way and the current antenna elevation angle is within a predetermined range, and a radio wave shielding warning signal is generated only when the difference is within a predetermined range.

Therefore, in claim 4, when the antenna in claim 2 is made into a biaxially rotatable antenna, the same rapid radio wave shielding warning as in claim 2 can be ensured.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an antenna tracking device according to a first embodiment of the present invention. As shown in this figure, this embodiment includes an antenna 10. The antenna 10 is an antenna having predetermined directivity, and is placed, for example, on the top of a moving object. Specifically, there are parabolic antennas, phased array antennas, etc., which usually have an exterior covered with a radome or the like to protect them from rain.

Further, in this embodiment, an azimuth axis driving means 12 for rotationally driving the antenna 10 around the azimuth axis is provided. The azimuth axis driving means 12 has a configuration such as a motor that rotates the azimuth axis, and is controlled by the azimuth axis control means 14. The azimuth axis control means 14 supplies a signal to the azimuth axis drive means 12 in accordance with the control target value supplied from the azimuth axis calculation means 16, and controls the azimuth of the antenna 10.

On the other hand, angle detecting means 18 composed of a rotary encoder or the like is provided to detect the angle of the antenna 10 around the azimuth axis. The quantity detected by the angle detection means 18 is the orientation of the antenna 10. This azimuth is usually an azimuth based on the moving object on which the device of the present embodiment is mounted, and therefore is expressed as an antenna azimuth Av. The antenna orientation Av is supplied to the orientation axis calculation means 16,
The azimuth axis calculation means 16 compares the antenna azimuth Av with the control target value, and supplies a signal to the azimuth axis control means 14 to control the azimuth of the antenna 10 so that the antenna azimuth Av matches the control target value. .

The control target value in the azimuth axis control means 16 is determined based on the satellite azimuth Sn supplied from the satellite azimuth calculation means 20 and the moving object azimuth V supplied from the moving object detection means 22. The satellite azimuth calculation means 20
The position of the moving body is acquired from a navigation device such as a PS, and the known satellite longitude is also acquired to determine the satellite direction Sn. Further, the moving body azimuth detection means 22 obtains the moving body azimuth V by taking in the moving body azimuth from an azimuth sensor such as an FGC (flux gate compass), and also taking in changes in the moving body azimuth from an angular velocity sensor. The azimuth axis calculation means 16 is
A control target value is determined based on the satellite azimuth Sn and the moving body azimuth V.

Here, the relationship between the satellite azimuth Sn and the moving body azimuth V is as shown in FIG. The satellite azimuth Sn obtained by the satellite azimuth calculation means 20 is, for example, the azimuth of the satellite S with respect to true north N. Furthermore, the moving body azimuth V is also the azimuth of the moving body V with true north N as a reference. When the antenna 10 has an orientation like A in FIG. 2, the antenna orientation Av detected by the angle detection means 18 matches the satellite orientation Sn except for the tracking error e. The azimuth axis calculation means 16 subtracts the moving body azimuth V from the satellite azimuth Sn, and sets the resulting angle as the control target value of the antenna 10. In this embodiment, the antenna orientation Av is controlled based on the satellite orientation Sn and the mobile orientation V output from the satellite orientation calculation means 20 and the mobile orientation detection means 22 so that the tracking error e is minimized. Therefore, if the antenna 10 captures the correction without tracking error,
Sn=V+Av.

On the other hand, in this embodiment, the antenna 1
A receiver 24 is provided which takes in the received output of zero. The receiver 24 converts the output of the antenna 10 into an IF of a predetermined frequency.
It is converted into a signal and supplied to the reception level detector 26 and demodulator 28. The reception level detector 26 detects the reception level from the IF signal and outputs a reception level signal whose value increases monotonically with respect to the reception level. Further, the demodulator 28
Demodulate the F signal and perform carrier detection using a PLL etc., and if a carrier is detected, the carrier detection signal C
Output D. Of these outputs, that is, the reception level signal and carrier detection signal CD, the reception level signal is:
The signal is supplied to a step track control circuit (not shown), and step track control related to the moving object orientation detecting means 22 is performed. The step track control is a control in which the control target value of the antenna 10 is gradually decreased and increased so that the reception level is the best.
Since it is disclosed in No. 40413, it will not be described here. Further, the carrier detection signal CD is the antenna direction Av
, satellite azimuth Sn, and mobile object azimuth V are taken into the radio wave shielding alarm calculation circuit 30.

The radio wave shielding alarm calculation circuit 30 has a structure related to the feature of this embodiment together with the radio wave shielding alarm means 32, and performs the radio wave shielding alarm calculation which is a feature of the present invention.

[0033] The radio wave shielding alarm calculation circuit 30 calculates the satellite direction S.
The tracking error e is determined based on n, the moving object orientation V, and the antenna orientation Av. That is, the tracking error e is determined according to the formula e=Sn-V-Av. Furthermore, the radio wave shielding alarm calculation circuit 30 determines whether this tracking error e is within a predetermined range. This range is set in consideration of the control accuracy of the azimuth control system of the antenna 10, and even if the radio waves from the satellite are blocked for a short time by an obstacle such as a building, the range will be This is a range in which it can be assumed that the satellite will not escape depending on the movement and other factors.

If it is determined as a result of such determination that the tracking error e is within a predetermined range, the radio wave shielding alarm calculation circuit 30 determines whether or not the carrier detection signal CD is generated. do. That is, the carrier detection signal C
By generating D, it is determined whether the antenna 10 is successfully receiving radio waves from the satellite. The radio wave shielding warning arithmetic circuit 30 detects when both the conditions related to the tracking error e and the conditions related to the carrier detection signal CD are satisfied, that is, even though the antenna 10 is within the azimuth range in which the satellite can be captured. When the carrier detection signal CD is generated, a radio wave shielding alarm signal is generated, and the radio wave shielding alarm means 32 issues a warning to the occupants of the moving object by means of display, sound, etc.

Therefore, in this embodiment, the antenna 1
Radio wave shielding will be detected without completing a complete orbit around 0, and an alarm will be issued. That is, a warning is issued to the occupant without waiting for the time required for the antenna 10 to go around the entire circumference, and the occupant can take corresponding measures. Therefore, the device becomes more usable.

FIG. 3 shows the configuration of an antenna tracking device according to a second embodiment of the present invention. The embodiment shown in this figure differs from the first embodiment in that it does not include the satellite orientation calculation means 20 and the mobile object orientation calculation means 22, but includes a satellite orientation search control circuit 34, a mobile object angular velocity detection means 36, and a bearing register 38. , a search/tracking changeover switch 40, and an adder 42.

In this embodiment, when the antenna 10 attempts to initially capture a satellite, the satellite azimuth search control circuit 34 operates. That is, in response to power-on, a satellite search command, etc., the satellite azimuth search control circuit 34 generates a search angle and supplies it to the bearing register 38 via the search/tracking switch 40. Satellite direction search control circuit 3
For example, the structure of No. 4 is based on the patent application No.
240413, etc., so it will not be explained in detail here. The satellite direction search control circuit 34 includes a demodulator 2
The generation of the search angle continues until the carrier detection signal CD is obtained from 8. The search angle generated by the satellite azimuth search control circuit 34 is supplied to an adder 42 provided in front of the bearing register 38 via a search/tracking switch 40, and the contents of the bearing register 38 are determined by the output of the adder 42. As a result, the contents of the bearing register 38 gradually increase. The value thus obtained, that is, the integral value of the search angle, is supplied to the azimuth axis calculation means 16 and is adopted as the control target value for the antenna 10. When the direction of the antenna 10 is controlled according to this control target value, the antenna 10 captures the satellite at some point, and therefore the demodulator 28 outputs the carrier detection signal C.
D is generated. When the carrier detection signal CD is generated, the satellite azimuth search control circuit 34 ends the search operation accordingly, and the search/tracking changeover switch 40 is switched to the mobile object angular velocity detection means 36 side. This causes a transition to normal operation.

In normal times, the increase/decrease dV in the moving object orientation detected by the moving object angular velocity detection means 36 is supplied to the adder 42 via the search/tracking changeover switch 40 . The moving object angular velocity detection means 36 is, for example, a rate sensor, and the moving object direction V is obtained by integrating its output. Since the adder 42 is placed before the bearing register 38 and updates the contents of the bearing register 38 based on the result, the contents of the bearing register 38 after transition to normal operation are the contents obtained by the search. The moving body orientation V is based on In the following description, the contents of the bearing register 38 at the time of initial acquisition will be expressed as V0.

When the contents of the bearing register 38 are sequentially updated by the operation of the moving body angular velocity detection means 36, the azimuth axis calculation means 16 changes the control target value accordingly and executes the azimuth control of the antenna 10. . Therefore, in this embodiment, the azimuth of the antenna 10 is controlled in accordance with changes in the azimuth of the moving object, thereby tracking the satellite.

Furthermore, in this embodiment, when the radio waves from the satellite are blocked by an obstacle such as a building and are no longer received by the antenna 10, the radio wave shielding alarm calculation circuit 30 generates a radio wave shielding alarm signal. An alarm is issued by the radio wave shielding alarm means 32. The conditions for generating the radio wave shielding alarm signal in the radio wave shielding alarm calculation circuit 30 are as shown in FIG. 4, unlike the embodiment shown in FIG.

The radio wave shielding alarm calculation circuit 38 takes in the moving object orientation V which is the content of the bearing register 38, the antenna orientation detected by the angle detection means 18 as Av, and the carrier detection signal CD, and generates a radio wave shielding alarm. generate a signal. Here, the contents of the bearing register 38 when the satellite is initially captured by the satellite azimuth search control circuit 34 are taken into the radio wave shielding alarm calculation circuit 30 as the mobile body azimuth V at that time. This radio wave shielding warning calculation circuit 30 averages the antenna orientation with respect to this reference value V0 and estimates it as the current satellite orientation. However, this averaging is performed only when the carrier detection signal CD is continuously obtained after the reference value V0 is obtained. The estimated value <Sv0> obtained in this way can be used as the azimuth of the satellite even if the antenna 10 loses sight of the satellite immediately after this. Therefore, the radio wave shielding alarm calculation circuit 3
0 indicates that the carrier detection signal If a CD cannot be obtained, a radio wave shielding alarm signal is issued to cause the radio wave shielding alarm means 32 to issue an alarm.

In order to calculate the estimated value <Sv0>, the initial acquisition of the satellite is performed by the satellite azimuth search control circuit 34, for example, every time the antenna 10 reacquires the satellite or at every predetermined period.

[0043] In this way, also in this embodiment, a prompt warning similar to that of the first embodiment shown in FIG. 1 is ensured. Furthermore, this embodiment can be constructed using an inexpensive moving body angular velocity detection means 36 such as a rate sensor, and the same effect can be achieved with an inexpensive device.

In the above description, the antenna 10 is an antenna that can be rotated only around the azimuth axis, but the present invention is also applicable to an antenna that can be rotated about two axes. For example, if the antenna 10 is an antenna that rotates not only around the azimuth axis but also around the elevation axis, the condition for generating a radio wave shielding warning signal is that the antenna 10 belongs to an elevation angle range in which it is expected to capture a satellite. All you have to do is add a condition to that effect. In this way, while driving the antenna 10 in two axes, it is possible to quickly detect radio wave shielding and issue a radio wave shielding alarm.

[0045]

[Effect of the invention] As explained above, claim 1 of the present invention
According to the above, in a device that controls the antenna orientation based on the satellite orientation Sn and the mobile object orientation V, it is possible to quickly generate a radio wave shielding warning without making the antenna go around the entire circumference. This improves the usability of the device and broadens its scope of application. Furthermore, there is no need to worry about equipment failure, interruption of calls, etc., and the psychological burden on the user of the device is reduced, resulting in a device that can be used with greater peace of mind.

Further, according to claim 2 of the present invention, in a device that detects the change in dV of the orientation of a moving object and controls the orientation of the antenna, it is possible to issue a prompt warning as in claim 1.

Furthermore, according to claim 3, the satellite orientation Sn
In the device that controls the azimuth and elevation angle of the antenna based on the azimuth V of the moving body, it is possible to issue a prompt warning as in claim 1.

[0048] According to claim 4, in a device that controls the antenna azimuth and elevation angle based on the change in dV of the moving body orientation, it is possible to issue a prompt warning as in claim 2.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an antenna tracking device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship of orientations in the first embodiment.

FIG. 3 is a block diagram showing the configuration of an antenna tracking device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the relationship of orientations in a second embodiment.

[Explanation of symbols]

10 Antenna 12 Azimuth axis drive means 14 Azimuth axis control means 16 Azimuth axis calculation means 18 Angle detection means 20 Satellite direction calculation means 22 Mobile object direction detection means 24 Receiver 28 Demodulator 30 Radio wave shielding alarm calculation circuit 32 Radio wave shielding alarm means 34 Satellite direction search control circuit 36 Moving body angular velocity detection means 38 Bearing register 42 Adder Sn Satellite direction V Mobile direction Av Antenna direction CD carrier detection signal dV Increase/decrease in moving object direction

Claims (4)

[Claims] 1. An antenna rotatably mounted on a moving body around an azimuth axis and having a predetermined directivity, an angle detection means for detecting an antenna azimuth Av with the moving body as a reference, and an antenna azimuth Av to be detected. a drive control means for driving the antenna so that the antenna azimuth coincides with a control target value; and an azimuth axis calculation means for calculating a control target value of the antenna azimuth Av based on the absolute azimuth Sn of the satellite and the mobile object azimuth V. In an antenna tracking device that tracks a satellite while compensating for movement and rotation of the satellite, carrier detection means detects that the antenna is suitably capturing the satellite and generates and outputs a carrier detection signal;
From the satellite's absolute azimuth Sn, the moving object azimuth V and the antenna azimuth A
Find the tracking error e by subtracting the sum of v, determine whether the tracking error e is within a predetermined range, and generate a radio wave shielding alarm signal if it is within the predetermined range and no carrier detection signal is generated. An antenna comprising: a radio wave shielding alarm calculation circuit that issues a radio wave shielding alarm calculation circuit; and a radio wave shielding alarm means that issues a predetermined alarm in response to a radio wave shielding alarm signal; Tracking device. 2. An antenna rotatably mounted on a moving body around an azimuth axis and having a predetermined directivity; angle detection means for detecting an antenna azimuth Av with respect to the moving body; and an antenna azimuth Av to be detected. a drive control means for driving the antenna so that it matches a control target value; a carrier detection means for detecting that the antenna is suitably capturing the satellite and generating and outputting a carrier detection signal; and at least when initially capturing the satellite. antenna direction A until a carrier detection signal is obtained at
A satellite azimuth search control circuit that causes the antenna to orbit by gradually changing the control target value of v; a mobile azimuth detection means that detects a change dV in the azimuth of the mobile body; and a control circuit for controlling the antenna azimuth Av in accordance with the change dV in the azimuth of the mobile body. An azimuth axis calculation means for sequentially changing and setting a target value, in an antenna tracking device that tracks a satellite while compensating for movement and turning of a moving object, the moving object azimuth at least when a carrier detection signal is obtained. Using V0 as a reference, calculate the estimate of the average value of the antenna orientation for a certain period after that point, and find the estimated value of the satellite orientation < S
v0>, find the tracking error <e> as the difference between the estimated value of the satellite orientation <Sv0> and the antenna orientation Av based on the current mobile object orientation V, and determine whether the tracking error <e> is within a predetermined range. a radio wave shielding alarm arithmetic circuit that determines whether or not the carrier is present and generates a radio wave shielding alarm signal when the carrier detection signal is within a predetermined range and no carrier detection signal is generated; and a radio wave shielding that issues a predetermined alarm in response to the radio wave shielding alarm signal. 1. An antenna tracking device, comprising: an alarm means, and is characterized in that it issues an alarm when the antenna is blocked from a satellite by an obstacle. 3. The antenna tracking device according to claim 1, wherein the antenna is rotatable around an elevation axis;
The drive control means includes an elevation angle detection means for detecting the antenna elevation angle, and a satellite elevation angle input means for inputting the satellite elevation angle.
The antenna is driven so that the antenna elevation angle matches the satellite elevation angle, and the radio wave shielding warning calculation circuit determines whether the difference between the antenna elevation angle and the satellite elevation angle is within a predetermined range, and only transmits radio waves if it is within the predetermined range. An antenna tracking device characterized by generating a shielding alarm signal. 4. The antenna tracking device according to claim 2, wherein the antenna is rotatable around an elevation axis;
The drive control means drives the antenna so that the antenna elevation angle matches the satellite elevation angle, and the radio wave shielding alarm calculation circuit detects the antenna elevation angle at least during a period when a carrier detection signal is obtained. The average value of is estimated as the current satellite elevation angle, and it is determined whether the difference between the current antenna elevation angle and the estimated satellite elevation angle is within a predetermined range, and only if it is within the predetermined range, a radio wave shielding warning signal is sent. An antenna tracking device characterized by generating.