JP5606217B2 - Tracking antenna device - Google Patents

Description

  The present invention relates to a tracking antenna device that tracks a pointing direction in an earth station device for mobile satellite communication.

  The tracking antenna device detects the directivity direction and the directivity direction error amount from various sensor information and received signals from the other party of communication, and mechanically controls the directivity direction (elevation angle and azimuth angle) of the antenna.

  A conventional tracking antenna device estimates the direction of a satellite-mounted antenna from its own position using a gyrocompass (orientation) or a GPS sensor, and monitors the integration amount of the angular velocity sensor and the reception level at the time of conical scanning in the pointing direction. Thus, the control amount for tracking the pointing direction is determined by estimating the attitude of the local station antenna and the pointing direction error (Non-Patent Document 1).

  On the other hand, in the phased array antenna, the elevation angle direction detects the pointing direction error by the monopulse method, the electronic scanning by the phased array antenna is performed, and the azimuth direction direction rotates the antenna by mechanical drive, and the reception level is monitored while monitoring the reception level. (Non-patent Document 2).

Inoue et al., Marine Antenna System for Realization of Next Generation Broadband, Journal of the JIME vol.41, No.6 (2006) Yoshida et al. Development and evaluation of ultra-thin satellite tracking antenna system, 2006 IEICE Society Conference, B-3-7, 2006, Kanazawa Kikuma, Adaptive Antenna Technology, Ohm Company (2003) Yoshida et al., Examination of configuration and control method of high-accuracy satellite automatic tracking antenna, IEICE Technical Report A ・ P2003-4

  The conventional tracking antenna device requires a highly accurate sensor when controlling the directivity direction mechanically, and also requires high speed and very fine control, so it has high performance (high torque, high speed). Multiple motors are required, which increases the cost. In addition, high performance motors increase their weight and increase antenna weight.

  On the other hand, the phased array antenna controls the directivity direction by adjusting the excitation distribution of each element. Even for one-dimensional scanning, it is necessary to provide at least several tens of phase shifters, which is very expensive.

  An object of the present invention is to provide a tracking antenna device capable of achieving high tracking performance, weight reduction, and cost reduction in consideration of a problem of a mechanical pointing device and a problem of a phased array antenna. .

Tracking antenna device of the present invention includes each directivity direction tracking means for coarse adjustment of the orientation of the antenna individually, and a plurality of antenna devices arranged in an array, the incoming direction of the signal arriving at each antenna, when deviation in a pointing direction error between the pointing direction of the antenna that the coarse adjustment occurs individually, the orientation error of controlling the phase and amplitude of the transmission signal each antenna to be transmitted from each antenna of the plurality of antenna devices A directivity direction error compensation unit that adjusts the directivity direction of the transmission signal of each antenna with higher accuracy than the directivity direction tracking unit by compensating each of them.

In tracking antenna device of the present invention, the pointing direction error compensation means includes a signal arrival direction estimation unit for calculating an arrival direction estimation value estimated direction of arrival of the Karaso signals arriving at each antenna, the control amount of the pointing direction tracking means and pointing detection unit that detects the orientation of each antenna based on, on the basis of the arrival direction estimation value and orientation of each antenna, directivity error detector for determining the orientation error of each antenna, Itaru coming direction estimation value using a weighting coefficient determination section that determines a weighting factor for controlling the excitation phase and amplitude of each antenna so as to compensate for orientation errors, the phase and amplitude of the transmission signal transmitted from each antenna depending on the weighting factor And a phase / amplitude controller for controlling.

  The tracking antenna device of the present invention is different from a normal phased array antenna in that each antenna device is provided with a directivity direction tracking means, and the directivity direction roughly adjusted by each antenna device is further adjusted, and the excitation phase and amplitude of each antenna are adjusted with high accuracy. High tracking performance can be obtained by performing the electrical directivity direction control. In particular, the directivity direction tracking means of each antenna device does not require a high-precision tracking function with high resolution, and can be dealt with only by coarse adjustment, so that weight reduction and cost reduction can be achieved with a simple configuration.

  Furthermore, by detecting a shift in the directivity direction of each antenna with respect to the arrival direction of the signal and correcting the antenna directivity direction, high tracking performance, light weight, and low cost can be achieved.

It is a figure which shows the structural example of the tracking antenna apparatus of Example 1 of this invention. FIG. 6 is a diagram illustrating an example of calculating an antenna pattern according to the first embodiment. It is a figure which shows the structural example of the tracking antenna apparatus of Example 2 of this invention. It is a figure which shows the example of calculation of the antenna pattern of Example 1,2. It is a figure which shows the example of calculation (enlarged figure) of the antenna pattern of Example 1,2.

FIG. 1 shows a configuration example of a tracking antenna device according to a first embodiment of the present invention.
In FIG. 1, the tracking antenna device according to the present embodiment includes two or more first to Nth antenna devices 10-1 to 10 -N, a transmission device 20, and a reception device 30.

  Each of the antenna devices 10-1 to 10-N includes an antenna 11 and a directivity direction tracking unit 12. The directivity direction tracking unit 12 of each antenna device 10 includes a satellite tracking mechanism (Non-Patent Document 4) such as closed loop control such as tracking control and open loop control such as vibration suppression control. However, since the high performance motor and the high accuracy sensor which are the conventional problems are not used, the tracking performance of each antenna device alone is inferior to the conventional tracking antenna device.

  The transmission device 20 includes a modulation unit 21 and phase / amplitude control units 22-1 to 22-N corresponding to the antenna devices. The receiving device 30 includes a maximum ratio combining unit 31 that combines the reception signals from the plurality of antennas 11, a demodulation unit 32 that demodulates the reception signal that has been combined with the maximum ratio, a signal arrival direction estimation unit 33 that estimates the signal arrival direction from the satellite, The weighting factor determining unit 34 determines a weighting factor based on the arrival direction estimation amount.

The signal arrival direction estimation unit 33 of the receiving device 20 uses the arrival direction estimation method (Non-patent Documents 2 and 3) represented by the Capon method, the MUSIC method, the monopulse method, and the like based on the received signal. Ask for. The weighting factor determination unit 34 uses the arrival direction estimation value θ estimated by the signal arrival direction estimation unit 33 to provide phase coefficients α _{1 to} α to be given to the phase / amplitude control units 22-1 to 22-N of the transmission device 20. _N and amplitude coefficients A _{1 to} A _N are determined. The phase / amplitude control units 22-1 to 22-N of the transmission apparatus 20 adjust the phase / amplitude of the signal modulated by the modulation unit 21 using the phase coefficient and the amplitude coefficient given from the weighting coefficient determination unit 34, Output to the antenna devices 10-1 to 10-N.

Here, the phase coefficients α _{1 to} α _N are _obtained by using α _k = πd _k sin θ / using the estimated arrival direction θ, the distances d _{1 to} d _N between the antennas from the arbitrarily defined antenna reference point, and the transmission signal wavelength λ. λ
k = 1, 2,..., N
Given in.

The amplitude coefficients A _{1 to} A _N are all set to 1 in this embodiment. However, when blocking occurs in some antenna apparatuses, the amplitude coefficient of the antenna apparatus is changed to a value such as 0 to adjust the combined output. You may do it.

By giving the phase coefficients α _{1 to} α _N and the amplitude coefficients A _{1 to} A _N to the phase / amplitude control units 22-1 to 22-N, the directivity direction error of each antenna is compensated, and the directivity The direction can be adjusted.

  FIG. 2 is a calculation example of the antenna pattern of the first embodiment, and is an example of analytically verifying the directivity direction tracking function of the tracking antenna device.

  The signal arrival direction was −5 degrees, and the directivity directions of the two antennas 1 and 2 constituting the tracking antenna apparatus were −5.25 degrees and −4.25 degrees, respectively. The antenna patterns after spatial synthesis when the individual antenna patterns of antennas 1 and 2 are set to the values obtained by the weight coefficient determination unit 34 in the phase / amplitude control units 22-1 and 22-2 are shown. The satellite tracking antenna for ship-borne use in the Ku band requires a pointing direction error of 0.2 degrees. In this embodiment, as shown in FIG. 2, even if the individual antenna directivity directions deviate from the required performance (antenna 1 error: -0.25 degrees, antenna 2 error: 0.75 degrees), the main beam of the combined antenna pattern is It can be confirmed that the error is within 0.2 degrees.

  As described above, in the configuration of the first embodiment, each antenna device does not have a high-performance motor or a high-precision sensor, and thus the directivity direction tracking performance of the single antenna is inferior. The required performance can be satisfied by detecting the direction error and performing electrical control to cancel it.

FIG. 3 shows a configuration example of the tracking antenna device according to the second embodiment of the present invention.
The tracking antenna apparatus according to the present embodiment is the same as the tracking antenna apparatus according to the first embodiment illustrated in FIG. A pointing direction detector 13 for detecting the pointing direction is provided. Furthermore, the receiving device 30 includes a pointing error detection unit 35 that obtains a pointing error from the results of the pointing direction detection unit 13 and the signal arrival direction estimation unit 33 of each of the antenna devices 10-1 to 10-N. The weighting factor determination unit 34 is based on the arrival direction estimation amount obtained by the signal arrival direction estimation unit 33 and the pointing error amount obtained by the pointing error detection unit 35, and the phase / amplitude control units 22-1 to 22 of the transmission device 20. Determine the weighting factor given to -N. Other configurations are the same as those of the first embodiment.

Specifically, the directivity direction detector 13 of each of the antenna devices 10-1 to 10 -N obtains the directivity directions θ + φ _{1 to} θ + φ _N of the antenna 11. The pointing error detection unit 35 uses the directivity directions θ + φ _{1 to} θ + φ _N and the arrival direction estimation value θ obtained by the signal arrival direction estimation unit 33 using the arrival direction estimation method described in the first embodiment. estimating a pointing error phi ₁ to [phi] _N of 11-1 to 11-N. Using the θ value and the pointing errors φ _{1 to} φ _N obtained at this time, the weight coefficient determination unit 34 determines the weight coefficient to be given to the phase / amplitude control units 22-1 to 22-N of the transmission device 20.

  As the directivity error of each antenna increases, the radiated power in the signal arrival direction of each antenna decreases. The correction coefficient obtained by the weighting coefficient determination unit 34 according to the first embodiment is a correction coefficient that maximizes the output signal in the arrival direction, but a slight pointing direction error remains. Therefore, in the second embodiment, a coefficient for correcting the residual pointing direction error is determined. Here, the pointing error was averaged, and based on that information, the signal synthesis pattern was shifted outside the arrival direction by shifting it in the direction opposite to the relative positional relationship between the averaged pointing error direction and arrival direction. Perform peak suppression.

The phase coefficients β ₁ to β _N given to the transmission side are obtained by using the directivity errors φ _{1 to} φ _N , the distances d _{1 to} d _N between the antennas from the arbitrarily defined antenna reference point, the transmission signal wavelength λ, and the coefficient γ. _k = α _k + γ (πd _k sin ((φ ₁ + φ ₂ +... + φ _N ) / N) / λ)
= Πd _k (sin θ + γ sin ((φ ₁ + φ ₂ +... + Φ _N ) / N)) / λ
k = 1, 2,..., N
Given in.

The first term is α _k obtained in the first embodiment, and the residual pointing error is corrected by the second term. In this embodiment, γ = 0.125. This coefficient γ is a coefficient depending on the original antenna pattern and the combined antenna pattern determined by the distance between the antennas, etc., and needs to be designed appropriately for each system. Specifically, it is desirable to make it equal to or less than the value of (the combined antenna beam width / original antenna beam width).

The amplitude coefficients B _{1 to} B _N are all set to 1 in the present embodiment, but when the antenna directivity direction deviation φ _k is large or when blocking to some antenna apparatuses occurs, the coefficient of the antenna apparatus is set to a value such as 0. The composite output may be adjusted by changing the value.

By providing the phase coefficients α _{1 to} α _N and amplitude coefficients B _{1 to} B _N to the phase / amplitude control units 22-1 to 22-N, the directivity direction error of each antenna is compensated, and the directivity is set. The direction can be adjusted.

  FIG. 4 is a calculation example of the antenna pattern of the first and second embodiments, and is an example in which the pointing direction tracking function of the tracking antenna device is analytically verified. FIG. 5 is an enlarged view of the vicinity of the main beam in FIG.

  The signal arrival direction was −5 degrees, and the directivity directions of the two antenna apparatuses constituting the tracking antenna apparatus were −5.25 degrees and −4.25 degrees, respectively. The antenna patterns after spatial synthesis in Examples 1 and 2 are represented by a solid line and a one-dot chain line, respectively. The satellite tracking antenna for ship-borne use in the Ku band requires a pointing direction error of 0.2 degrees. In the first and second embodiments, even if each antenna directivity direction deviates from the required performance (antenna 1 error: -0.25 degrees, antenna 2 error: 0.75 degrees), the combined antenna pattern main beam has an error of 0.2 degrees. It can be confirmed from FIG. In addition, in Example 1, the directivity direction was -5.05 degrees, whereas in Example 2, the directivity direction was -4.99 degrees, approaching 5 degrees.

  As described above, in the configuration of the second embodiment, each antenna device does not have a high-performance motor or a high-precision sensor, and thus the directivity direction tracking performance of the single antenna is inferior. The required performance can be satisfied by detecting the direction error and performing electrical control to cancel it.

DESCRIPTION OF SYMBOLS 10 Antenna apparatus 11 Antenna 12 Directional direction tracking part 13 Directional direction detection part 20 Transmitting apparatus 21 Modulation part 22 Phase / amplitude control part 30 Receiving apparatus 31 Maximum ratio composition part 32 Demodulation part 33 Signal arrival direction estimation part 34 Weight coefficient determination part 35 Pointing error detector

Claims (2)

Each comprise a directional direction tracking means for coarse adjustment of the orientation of the antenna individually, and a plurality of antenna devices arranged in an array,
A transmission signal transmitted from each antenna of the plurality of antenna devices when a directivity direction error, which is a deviation between the arrival direction of the signal arriving at each antenna and the directivity direction of each of the roughly adjusted antennas, occurs individually. of by respective uncompensated SL directivity direction error of each antenna by controlling the phase and amplitude, orientation error compensation means for adjusting the orientation of the transmission signal of each antenna to high accuracy than the directivity direction tracking means A tracking antenna device comprising: and. The tracking antenna device according to claim 1,
The pointing direction error compensating means is
A signal arrival direction estimation unit for calculating the arrival direction estimation values estimated direction of arrival of the Karaso signals arriving at each antenna,
A directivity direction detector that detects the directivity direction of each antenna based on the control amount of the directivity direction tracking means ;
And on the basis of the said arrival direction estimation value and orientation of each antenna, the directional error detector for determining the orientation error of each antenna,
Using front Kiita coming direction estimation value, a weight coefficient determination section that determines a weighting coefficient for controlling the excitation phase and amplitude of each antenna so as to compensate for the orientation error,
A tracking antenna apparatus comprising: a phase / amplitude control unit that controls a phase and an amplitude of a transmission signal transmitted from each antenna according to the weighting factor.

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