JP6056442B2 - Tracking antenna device - Google Patents

Description

  The present invention relates to an antenna device or a tracking receiving device suitable for monopulse tracking in a satellite communication earth station antenna.

  The monopulse tracking for satellite communication receives the basic mode and higher-order mode (TM01, TE01, TE21 mode, etc.) of the incoming radio wave of the satellite to be tracked, and the higher-order mode has a null point in the boresight direction. The satellite is tracked by controlling the elevation angle and azimuth angle of the antenna so that the higher-order mode component becomes zero.

  Conventionally, in tracking antenna devices used for such monopulse tracking for satellite communication, circularly polarized waves coming from the satellite to the ground become elliptically polarized waves due to the attitude of the satellite or rainfall, etc. There is one that compensates for an error (see, for example, Patent Document 1). In general, it is well known that a tracking error signal for compensating an error is calculated using a sum signal (SUM) and a difference signal (ERROR) (see, for example, Patent Document 2).

JP 2002-196058 A JP 2012-202945 A

  However, the conventional tracking antenna device uses an offset antenna or beam feed system, although circular polarization arriving from the satellite to the ground is considered to be elliptically polarized due to the attitude of the satellite or rainfall. There was a problem that a null shift caused by an asymmetric structure such as an antenna was not taken into account, and a problem that a higher precision compensation was not taken into consideration.

  The null shift due to the asymmetric structure of the antenna device cries in different directions for the main polarization and the reverse polarization, whereas the configuration of Patent Document 1 can compensate only for the main polarization. Null shift increases, and tracking accuracy is greatly degraded during reverse polarization tracking.

  In addition, in the conventional tracking antenna device, the peak position of the received sum signal also cries in different directions for the main polarization and the reverse polarization, so that even if the null of the tracking error signal is corrected in the main axis direction, the peak of the main polarization There was also a problem that the pointing loss increased without matching the direction.

  The present invention has been made to solve the above-described problems, and the arrival polarization from the satellite in the satellite communication ground station is not constant, and when the null position of the tracking error signal is changed by the polarization, It is an object of the present invention to provide a tracking antenna device that can compensate for or calculate the orbital position and improve tracking accuracy even when the null position changes due to its own weight deformation or an asymmetric structure.

Tracking antenna device according to a first aspect of the invention, a tracking antenna system for tracking and receives circularly polarized waves, an antenna unit which have a electrically asymmetric structure, AZ axis the antenna portion And the antenna drive unit driven in the EL axis direction, and the received sum signal of the right-handed component and the left-handed component are respectively calculated from the fundamental mode of the circularly polarized wave received by the antenna unit, and the antenna unit received the A feeding unit that calculates a reception difference signal between a right-handed component and a left-handed component from a higher-order mode of circular polarization, and an XPD calculation unit that calculates a cross polarization discrimination degree from the received sum signal calculated by the feeding unit. If, from the cross polarization discrimination of the XPD calculation unit has calculated, in the beam pattern of the antenna portion, to calculate the amount of null shift caused by the structure, determining the null shift compensation value Nurushi And a tracking signal correction unit that corrects a tracking error signal obtained from the reception sum signal and the reception difference signal, using the null shift correction value determined by the null shift correction value generation unit, The tracking error is corrected by driving the antenna unit by the antenna driving unit by an angle corresponding to the tracking error signal corrected by the tracking signal correcting unit.

The tracking antenna device according to the invention of claim 2, a tracking antenna system for tracking and receives circularly polarized waves, an antenna unit which have a electrically asymmetric structure, the antenna unit receives the The received sum signal of the right-handed component and the left-handed component is calculated from the fundamental mode of circular polarization, respectively, and the reception difference between the right-handed component and the left-handed component from the higher-order mode of the circularly polarized wave received by the antenna unit. From the feeding unit that calculates each signal, the XPD calculation unit that calculates the cross polarization discrimination from the received sum signal calculated by the feed unit, and the cross polarization discrimination calculated by the XPD calculation unit, the antenna in parts of the beam pattern, and calculates the amount of null shift caused by the structure, and null shift correction value generation unit for determining a null shift correction value, the the null shift compensation value generating unit has determined Nurushifu Using the correction value, a tracking signal correction unit that corrects a tracking error signal obtained from the received sum signal and the reception difference signal, and the antenna unit received based on the tracking error signal corrected by the tracking signal correction unit And an antenna control unit that calculates the orbital position of the transmission source transmitting the circularly polarized wave.

  The tracking antenna device according to a third aspect of the present invention is the tracking antenna device, wherein the XPD calculator deviates from a range in which the calculated cross polarization discrimination is sandwiched between a predetermined first upper limit value and a predetermined first lower limit value. In this case, a value closer to the difference between the predetermined first upper limit value and the predetermined first lower limit value is sent to the null shift correction value generation unit as the cross polarization discrimination degree. It is a thing of Claim 1 or 2.

  In the tracking antenna device according to the invention of claim 4, the null shift correction value generation unit is a value outside the range in which the generated null shift correction value is sandwiched between a predetermined second upper limit value and a predetermined second lower limit value. In this case, with respect to the deviated value, a closer value of the predetermined second upper limit value and the predetermined second lower limit value is set as the null shift correction value. It is a thing in any one of Claim 1, 2, 3.

  5. The tracking antenna device according to claim 5, wherein the null shift correction value generation unit sets the null shift correction value to 0 when the set null shift correction value is equal to or less than a predetermined value. belongs to.

  In the tracking antenna device according to the invention of claim 6, the tracking signal correction unit does not correct the tracking error signal when the null shift correction value set by the null shift correction value generation unit is equal to or less than a predetermined value. It is a thing of Claim 4.

  As described above, according to the first aspect of the present invention, when the position of the null of the tracking error signal changes due to the polarization, the antenna portion is asymmetrical, and the null point changes in a different direction between the main polarization and the reverse polarization. Even in such a case, it is possible to obtain a tracking antenna device that can correct the tracking accuracy and improve the tracking accuracy.

  According to the invention of claim 2, when the position of the null of the tracking error signal changes due to the polarization, or when the antenna part is asymmetrical and the null point changes in a different direction between the main polarization and the reverse polarization. Even if it exists, the tracking antenna apparatus which can calculate the orbital position of the transmission source which is transmitting circularly polarized wave can be obtained.

  According to the invention of claim 3, it is possible to obtain a tracking antenna device that can prevent the null shift correction value from deviating from the value of the cross polarization discrimination degree.

  According to the invention which concerns on Claim 4, the tracking antenna apparatus which can prevent the deviation of a null shift correction value can be obtained.

  According to the invention which concerns on Claim 5 or 6, the tracking antenna apparatus which does not correct | amend an unnecessary tracking error signal can be obtained.

It is a block diagram of the tracking antenna apparatus which concerns on Embodiment 1 of this invention. It is a block diagram of the electric power feeding part of the tracking antenna apparatus which concerns on Embodiment 1 of this invention. It is a block diagram of ACU and the antenna drive part of the tracking antenna apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the XPD calculation part of the tracking antenna apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the null shift correction value production | generation part of the tracking antenna apparatus which concerns on Embodiment 1 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. In FIGS. 1, 2, and 3, reference numeral 1 denotes an antenna unit that receives circularly polarized radio waves (arrival radio waves) in a tracking antenna apparatus that receives and tracks circularly polarized radio waves. The antenna unit 1 has an asymmetric structure or a structure that is deformed by its own weight. Specifically, the antenna unit 1 has an asymmetric structure or a structure that is deformed by its own weight, that is, an electrically asymmetric structure. The received radio wave arriving at the antenna unit 1 passes through asymmetric propagation paths such as the main mirror 1a and the sub mirror 1a, the mulberry reflector 1c, and the converging reflector 1d included in the antenna unit 1, and the primary radiator 1e. The received signal is transmitted to the power supply unit 2 to be described later. 2 calculates the received sum signal (SUM) of the right-handed component and the left-handed component from the fundamental mode of the circularly polarized wave received by the antenna unit 1, and from the higher-order mode of the circularly polarized wave received by the antenna unit 1, It is a power feeding unit that calculates a reception difference signal (ERROR) between a right-handed component and a left-handed component. The tracking error signal is obtained by controlling the antenna drive unit 3 described later in order to correct an error caused by the antenna unit 1 or an error caused by circular polarization not being completely circular polarization (that is, elliptical polarization). This is a signal for correction. Therefore, the tracking error signal can be said to be a control signal for the antenna driving unit 3 described later. In the drawings, the same reference numerals denote the same or corresponding parts, and detailed descriptions thereof are omitted.

  The power feeding unit 2 includes a high-order mode coupler (mode separation unit 2a) that extracts a received signal derived from an incoming radio wave input from the antenna unit 1 as a fundamental mode and a higher-order mode, and a basic mode of the received signal extracted by the mode separation unit 2a. And the sum of the received signals of the right-handed component of the fundamental mode separated by the polarization separation unit 2b, the polarization separation unit 2c, and the polarization separation unit 2b, which separate the higher-order mode into a right-handed component and a left-handed component, respectively. Sum signal calculation section 2d, sum signal calculation section 2e for calculating the sum of the received signals of the left-handed component in the basic mode separated by the polarization separation section 2b, and reception of the higher-order mode right-handed component separated by the polarization separation section 2c A difference signal calculation unit 2f that calculates a reception difference signal (right rotation) from the signal, and a difference signal calculation unit 2g that calculates a reception difference signal (left rotation) from the reception signal of the left-handed component of the higher-order mode separated by the polarization separation unit 2c Consists of . In the drawings, the same reference numerals denote the same or corresponding parts, and detailed descriptions thereof are omitted.

  1, 2, and 3, 3 is an antenna driving unit that drives the antenna unit 1 in the AZ axis direction and the EL axis direction, and 4 is a power supply for each of the extracted basic mode reception sum signal and higher-order mode reception difference signal. A plurality of low noise amplifiers (LNAs) that amplify signals that are separated and extracted into right-handed signals and left-handed signals in the unit, and 5 is a down converter that converts signals amplified by LNA4 into IF signals , 6 is a receiving unit (RCVR: Receiver) that performs reception processing of a right-handed signal (right-handed component) and a left-handed signal (left-handed component) of the received sum signal that is an IF signal from the downconverter 5, and 7 is from the downconverter 4. The right-handed signal (right-handed component) and left-handed signal (left-handed component) of the received sum signal that has become the IF signal, the right-handed signal (right-handed component) and left-handed signal of the received difference signal A tracking receiver (TRK RCVR: Track Receiver) that performs phase correction and gain correction of each signal from the signal (left-handed component), and 8 is an antenna control unit (ACU: Antenna Control Unit). In the drawings, the same reference numerals denote the same or corresponding parts, and detailed descriptions thereof are omitted.

  1, 2, and 3, 9 intersects the received sum signal (received sum signal (right-handed), received sum signal (left-handed)) calculated by the power feeding unit 2 (sum signal calculating unit 2 d, sum signal calculating unit 2 e). XPD calculation unit 10 for calculating the polarization discrimination degree is a null shift caused by the asymmetric structure of the antenna unit 1 or a structure deformed by its own weight in the beam pattern of the antenna unit 1 based on the cross polarization identification degree calculated by the XPD calculation unit 9. It is a null shift correction value generation part which calculates the quantity of and determines a null shift correction value. The XPD calculation unit 9 and the null shift correction value generation unit 10 are formed in the antenna control unit 8 or the tracking reception unit 7. FIG. 1 shows a case where the XPD calculation unit 9 and the null shift correction value generation unit 10 are provided in the antenna control unit 8. Reference numeral 11 denotes a tracking signal correction unit (correction value addition unit) that corrects the tracking error signal using the null shift correction value determined by the null shift correction value generation unit 10. The antenna control unit 8 (control unit 8, orbit position calculation unit 8) based on the tracking error signal corrected by the tracking signal correction unit 11 is a transmission source (satellite) that transmits the circularly polarized wave received by the antenna unit 1. ) Is calculated. In the drawings, the same reference numerals denote the same or corresponding parts, and detailed descriptions thereof are omitted.

  The tracking antenna device according to the first embodiment can correct the null shift generated in the antenna unit 1 having an electrically asymmetric structure and improve the tracking accuracy. In the tracking antenna device according to the first embodiment, when the XPD calculation unit 9 and the null shift correction value generation unit 10 are provided in the antenna control unit 8, the tracking reception unit 6 performs “a right-handed signal and a left-handed signal of a reception difference signal”. ”And“ Tracking error signal calculation method such as correlation detection between the right-handed signal and the left-handed signal of the received sum signal ”is converted into signals of ΔAZ and ΔEL which are error information of angles on the AZ axis and EL axis. It becomes an error signal (tracking error signal (ΔAZ), tracking error signal (ΔEL)). The received signal (received sum signal) and the tracking error signal are transmitted to the antenna control unit 8.

  The tracking error signals of ΔAZ and ΔEL transmitted to the antenna control unit 8 are sent to the null shift of the antenna unit 1 by the XPD calculation unit 9 and the null shift correction value generation unit 11 and the tracking signal correction unit 11 provided in the antenna control unit 8. The antenna control unit 8 generates an antenna control signal that is a control signal (AZ) and a control signal (EL) for controlling the antenna driving unit 3 for correcting the antenna, and transmits the antenna control signal to the antenna driving unit 3 to transmit the antenna unit 1. To track the satellite. That is, the tracking antenna device according to Embodiment 1 corrects the tracking error by driving the antenna unit 1 by the antenna driving unit 3 by an angle corresponding to the tracking error signal corrected by the tracking signal correcting unit 11. is there.

  The null shift correction processing in the antenna control unit 8 will be described in detail. Each signal input to the ACU 8 is subjected to null shift correction in the XPD calculation unit 9 and the null shift correction value generation unit 10 which are null shift correction processing units in the ACU 8. The XPD calculator 9 calculates a cross polarization discrimination (XPD) between the right-handed signal and the left-handed signal of the received sum signal.

  The null shift correction value generation unit 10 calculates correction values for the AZ plane and the EL plane of the antenna unit 1 from the cross polarization discrimination degree calculated by the XPD calculation unit 9. By adding the AZ plane correction value and EL plane correction value to the tracking error signals of AZ and EL transmitted from the tracking receiving unit 7 in the tracking signal correcting unit 11, the tracking error signal subjected to the null shift correction is obtained. can get.

  Next, detailed processing of the XPD calculation unit 9 will be described using the flowchart shown in FIG. First, using the following formula (1), the XPD calculation unit 9 calculates the cross polarization discrimination from the right-handed component (XL) and left-handed component (XR) of the received sum signal (STEP 1).

  X ′ in Equation (1) is the cross polarization discrimination. When the sign of X ′ is positive, it indicates the cross-polarization discrimination when the left-handed polarization is the main polarization. When the sign of X ′ is negative, the absolute value of X ′ is the right-handed polarization. It shows the cross polarization discrimination degree. Next, the XPD calculation unit 9 restricts the value of the cross polarization discriminating value with a threshold so as to be within a certain range. The relationship between the threshold value and the cross polarization discrimination degree X ′ is determined using the inequality of the following formula (2) (STEP 2).

  If the cross polarization discrimination is greater than or equal to the threshold + α, the cross polarization discrimination X is set to + α (STEP 3). If it is smaller than the threshold value α, it is determined by the inequality of the following formula (3) (STEP 4).

  Here, when the cross polarization discrimination degree is smaller than the threshold value + α and larger than −α, the cross polarization discrimination degree X is set to X ′. If it is -α or less, it is set to -α (STEP 5) (STEP 6). This is because if the absolute value of the cross polarization discrimination degree is large, the difference between the correction value calculated by the approximate expression when calculating the correction value described later and the actual null shift correction value becomes large.

  That is, if the calculated cross-polarization discrimination is a value outside the range between the predetermined first upper limit value (+ α) and the predetermined first lower limit value (−α), the XPD calculation unit 9 With respect to the deviated value, the closer one of the predetermined first upper limit value (+ α) and the predetermined first lower limit value (−α) is sent to the null shift correction value generation unit 10 as the cross polarization discrimination degree. It can be said that it is a thing. This corresponds to the processing of STEP3 and STEP6.

  Here, “α” mentioned as the first upper limit value (+ α) and the first lower limit value (−α) will be described. In an ideal circular polarization, the cross polarization discrimination (XPD) is infinite. However, when deriving an approximate expression (null shift correction expression) of the null shift amount at an arbitrary cross polarization discrimination (XPD) from the result of analysis or measurement, it is necessary to use a finite value of XPD. That is, if the lower limit value of XPD used for deriving the approximate expression is αmin and the upper limit value αmax, the approximate expression (null shift correction expression) is effective within the range. α is set within a range where the approximate expression is valid.

  Next, detailed processing of the null shift correction value generation unit 10 will be described using the flowchart shown in FIG. From the cross polarization discrimination degree X obtained by the XPD calculation unit 9, for example, a null shift correction value Y ′ is obtained by an approximate expression (null shift correction expression) shown in the following equation (4) (STEP 11).

  The null shift correction formula is calculated as an approximate formula by the null shift obtained by numerical calculation. Or you may calculate an approximate expression based on the result actually evaluated with the tracking antenna apparatus. The approximate expression may be an approximate expression using an exponential function or a logarithmic function in addition to the polynomial approximation of Expression (4). Furthermore, the degree of the polynomial may be higher or lower.

  Next, the null shift correction value generation unit 10 performs a process of restricting the null shift correction value within an arbitrary value range according to the threshold value. The relationship between the threshold value and the null shift correction value Y ′ is determined using the inequality shown in the following equation (5) (STEP 12).

  When the null shift correction value Y ′ is equal to or greater than the threshold + β, the null shift correction value Y is set to + β (STEP 13). If it is smaller than the threshold value β, it is determined by the following inequality (STEP 14).

  When the null shift correction value Y ′ is smaller than the threshold value + β and larger than −β, the null shift correction value Y is set to Y ′. If it is -β or less, it is set to -β (STEP 15) (STEP 16).

  That is, if the generated null shift correction value is a value outside the range between the predetermined second upper limit value (+ β) and the predetermined second lower limit value (−β), the null shift correction value generation unit 10 It can be said that a value closer to the offset value is a null shift correction value among the predetermined second upper limit value (+ β) and the predetermined second lower limit value (−β). This corresponds to the processing of STEP13 and STEP16.

  Here, “β” mentioned as the second upper limit value (+ β) and the second lower limit value (−β) will be described. β limits the amount of null shift correction. Even if there is a mistake in setting the null shift correction formula due to a human error or the like, abnormal operation of the antenna unit 1 (antenna driving unit 3) can be prevented by adding a restriction with an appropriate threshold.

  In the process of the null shift correction value generation unit 10, it is determined by the determination value S whether the calculated null shift correction value is added to or subtracted from the tracking error signal. When the determination value S is 0, the null shift correction value Ya is set to 0 (STEP 17) (STEP 18). If the determination value S is a value other than 0, the null shift correction value Ya is set to + Y (STEP 19). That is, when the determination value S is 0, the null shift correction value Ya is 0, which means that the null shift correction is not substantially performed. The null shift correction function can be switched ON / OFF by the determination value S. A case where the absolute value of the calculated null shift correction value is equal to or smaller than a predetermined value is a case where the determination value S is 0. This is because it is not necessary to correct the tracking error signal when the absolute value of the calculated null shift correction value is equal to or smaller than a predetermined value. In other words, the predetermined value can be said to be a small value that does not require the tracking error signal to be corrected.

  By these processes, the null shift correction value Ya for each of the AZ plane and the EL plane is calculated, and the tracking error signal for each of the AZ plane and the EL plane is corrected using that value. As shown in FIG. 3, the AZ plane correction value and the EL correction value output from the null shift correction value generation unit 10 are the tracking signal correction unit 11 (correction value addition unit 11) and the tracking error signal (ΔAZ) and tracking, respectively. The tracking error signal (ΔAZ) and the tracking error signal (ΔEL), which are added to the error signal (ΔEL) and corrected for correction, that is, the control signal (AZ) and the control signal (AZ) are transmitted to the antenna driving unit 3. Sent to. It can be said that the control signal (AZ) and the control signal (AZ) are antenna control signals for the AZ plane and the EL plane.

  The antenna driving unit 3 receives the control signal (AZ) (corrected tracking error signal (ΔAZ)) and the control signal (AZ) (corrected tracking error signal (ΔEL)) from the AZ axis and the EL axis or Either one of them is driven to move the antenna unit 1 to correct an error caused by the antenna unit 1 or an error caused by the fact that the circularly polarized wave is not completely circularly polarized (that is, elliptically polarized wave).

  The determination value S may be determined by the null shift correction value generation unit 10 or the tracking signal correction unit 11. In the case where the null shift correction value generation unit 10 performs the processing, it can be said that the null shift correction value generation unit 10 sets the null shift correction value to 0 (zero) when the set null shift correction value is equal to or less than a predetermined value. When the tracking signal correction unit 11 performs the tracking signal correction unit 11, the tracking error signal is not corrected when the null shift correction value set by the null shift correction value generation unit 10 is equal to or less than a predetermined value. . Not correcting the tracking error signal is synonymous with adding a null shift correction value as 0 (zero).

  So far, the case where the XPD calculation unit 9, the null shift correction value generation unit 10 and the tracking signal correction unit 11 (correction value addition unit 11), which are null shift correction processing units, are mounted on the antenna control unit 8 has been described. Further, the XPD calculation unit 9 and the null shift correction value generation unit 10 which are null shift correction processing units may be provided in the tracking reception unit 7, or the XPD calculation unit 9 and the null shift correction value generation unit 10 which are null shift correction processing units and a tracking signal. The correction unit 11 (correction value addition unit 11) may be provided in the tracking reception unit 7.

  When the XPD calculation unit 9 and the null shift correction value generation unit 10 are provided in the tracking reception unit 7, the antenna control unit 8 controls the antenna control signals for the AZ plane and the EL plane based on the tracking error signal corrected by the tracking reception unit 7. (Control signal (AZ) and control signal (AZ)) are generated and transmitted to the antenna driving unit 3 to drive the antenna to track the satellite. When the PD calculating unit 9, the null shift correction value generating unit 10, and the tracking signal correcting unit 11 (correction value adding unit 11) are provided in the tracking receiving unit 7, the tracking receiving unit 7 uses the antenna control signals (controls) of the AZ plane and the EL plane. A signal (AZ) and a control signal (AZ) are generated and transmitted to the antenna driving unit 3 to drive the antenna to track the satellite.

  The tracking antenna device according to the first embodiment calculates the null shift values of the main polarization and the reverse polarization from the cross polarization discrimination of the received sum signal in the antenna unit 1 having an electrically asymmetric structure, By automatically correcting the null position in the incoming polarization, the pointing loss can be reduced and the tracking accuracy can be improved. Of course, in the tracking antenna device according to the first embodiment, the antenna unit 1 is not an asymmetric structure or a structure deformed by its own weight (electrically asymmetric structure), or an asymmetric structure or a structure deformed by its own weight (electrically asymmetric structure). The present invention can be applied even when the degree of asymmetry or the degree of deformation is insignificant. That is, the tracking antenna device according to the first embodiment can be applied to highly accurate correction (compensation) when the position of the null of the tracking error signal changes.

  Further, the tracking antenna device according to Embodiment 1 receives a signal having a cross polarization generated by a radio wave propagation path and its own weight deformation and antenna asymmetry in the antenna unit 1 capable of receiving circular polarization, A device (mode separation unit 2a) that separates and extracts a fundamental mode signal and a higher-order mode signal from the received signal, and a device (polarization separation unit 2c) that separates and extracts a right-handed polarization and a left-handed polarization of a higher-order mode; A cross polarization discrimination degree is calculated from a device (polarization separator 2b) that separates and extracts the right-handed polarized wave and the left-handed polarized wave in the basic mode, and the right-handed polarized wave and the left-handed polarized wave in the separated basic mode. A calculation unit (XPD calculation unit 9), a calculation unit (null shift correction value generation unit 10) that calculates a null shift from the cross polarization discrimination degree, and a tracking error is compensated (corrected) based on the calculated null shift. It means for driving and controlling the antenna may be any one having a (antenna drive section 3).

  Furthermore, in tracking antenna apparatus according to Embodiment 1, antenna unit 1 capable of receiving circularly polarized waves receives signals having cross-polarized waves generated due to radio wave propagation paths, self-weight deformation and antenna asymmetry. Then, a device (mode separation unit 2a) that separates and extracts the fundamental mode signal and the higher-order mode signal from the received signal, and a device that separates and extracts the right-handed polarization and the left-handed polarization of the higher-order mode (polarization separation unit 2c). ), A right-handed polarized wave and a left-handed polarized wave in the basic mode (polarization separating unit 2b), and a cross-polarization discrimination degree from the right-handed polarized wave and the left-handed polarized wave in the separated basic mode. The calculating unit (XPD calculating unit 9) for calculating, the calculating unit (null shift correction value generating unit 10) for calculating the null shift from the cross polarization discrimination degree, and the antenna unit 1 received based on the calculated null shift Polarization may also be one having a transmission to have satellite means for calculating the orbital position (transmission source) (antenna control unit 8).

  In addition, the tracking antenna apparatus according to the first embodiment can be said to be a tracking receiver according to the first embodiment. The configuration in this case is as follows. A tracking receiver that receives and tracks a circularly polarized radio wave, and receives the sum of the right-handed component and the left-handed component from the fundamental mode of the circularly polarized wave received by the antenna unit 1 that receives the circularly polarized wave. Each signal is calculated, and the cross polarization identification is performed from the received sum signal calculated by the feeding unit 2 that calculates the reception difference signal between the right-handed component and the left-handed component from the higher-order mode of the circularly polarized wave received by the antenna unit 1. From the XPD calculation unit 9 for calculating the degree and the cross polarization discrimination degree calculated by the XPD calculation unit 9, the null shift in the beam pattern of the antenna unit 1 (generated by the asymmetric structure of the antenna unit 1 or the structure deformed by its own weight) Using the null shift correction value generation unit 10 that calculates the amount and determines the null shift correction value, and the null shift correction value determined by the null shift correction value generation unit 10, it is obtained from the reception sum signal and the reception difference signal. And a tracking signal correction unit 11 that corrects the tracking error signal, and an antenna driving unit that drives the antenna unit 1 in the AZ axis direction and the EL axis direction by an angle corresponding to the tracking error signal corrected by the tracking signal correction unit 11 The tracking error signal is sent to the antenna driving unit 3 so that 3 can be corrected.

  Similarly, the configuration of the tracking receiver according to the first embodiment is as follows. A tracking receiver that receives and tracks a circularly polarized radio wave, and receives the sum of the right-handed component and the left-handed component from the fundamental mode of the circularly polarized wave received by the antenna unit 1 that receives the circularly polarized wave. Each signal is calculated, and the cross polarization identification is performed from the received sum signal calculated by the feeding unit 2 that calculates the reception difference signal between the right-handed component and the left-handed component from the higher-order mode of the circularly polarized wave received by the antenna unit 1. From the XPD calculation unit 9 for calculating the degree and the cross polarization discrimination degree calculated by the XPD calculation unit 9, the null shift in the beam pattern of the antenna unit 1 (generated by the asymmetric structure of the antenna unit 1 or the structure deformed by its own weight) Using the null shift correction value generation unit 10 that calculates the amount and determines the null shift correction value, and the null shift correction value determined by the null shift correction value generation unit 10, it is obtained from the reception sum signal and the reception difference signal. A tracking signal correction unit 11 that corrects the tracking error signal, and an antenna that calculates the orbital position of the transmission source that transmits the circularly polarized wave received by the antenna unit 1 based on the tracking error signal corrected by the tracking signal correction unit 11 A control unit 8 (control unit 8, orbit position calculation unit 8) is provided.

1. ・ Antenna unit, 1a ・ ・ Primary mirror, 1b ・ ・ Kuwate plane mirror, 1c ・ ・ Focusing reflector, 1d ・ ・ Focusing reflector, 1e ・ ・ Primary radiator, 2 ・ ・ Feeding unit, 2a ・ ・ mode Separation unit, 2b ·· Polarization separation unit (basic mode), 2c · · Polarization separation unit (higher order mode), 2d · · Sum signal calculation unit (right-handed), 2e · · Sum signal calculation unit (left-handed) 2f ··· Difference signal calculation unit (right rotation) 2g · · Difference signal calculation unit (left rotation) 3 · · Antenna drive unit 4 · · Low noise amplifier (LNA) 5 · · Down converter, · · · Receiving unit (RCVR) 7. Tracking receiver (TRK RCVR) 8. Antenna control unit (ACU) (control unit, orbit position calculating unit) 9. XPD calculating unit 10. Null shift correction value generation 11. Tracking signal correction unit (correction value addition unit).

Claims (6)

A tracking antenna system for tracking and receives circularly polarized waves, an antenna unit which have a electrically asymmetric structure, and the antenna driving section for driving the antenna unit in the AZ axis and the EL axis, From the fundamental mode of the circularly polarized wave received by the antenna unit, a received sum signal of the right-handed component and the left-handed component is calculated, and the right-handed component is calculated from the higher-order mode of the circularly polarized wave received by the antenna unit. And a left-handed component, respectively, a feeding unit that calculates a reception difference signal, an XPD calculation unit that calculates a cross polarization discrimination from the received sum signal calculated by the feeding unit, and the cross-bias calculated by the XPD calculation unit. from the wave identification degree, in the beam pattern of the antenna portion, to calculate the amount of null shift caused by the structure, and null shift correction value generation unit for determining a null shift correction value, the null shift compensation value A tracking signal correction unit that corrects a tracking error signal obtained from the reception sum signal and the reception difference signal, using the null shift correction value determined by the generation unit, and the tracking signal corrected by the tracking signal correction unit A tracking antenna device that corrects a tracking error by driving the antenna unit by the antenna driving unit by an angle corresponding to an error signal. A tracking antenna system for tracking and receives circularly polarized waves, an antenna unit which have a electrically asymmetric structure, the fundamental mode of the circularly polarized waves in which the antenna unit receives the right旋成min A feeding unit that calculates a reception sum signal with a left-handed component and calculates a received difference signal between the right-handed component and the left-handed component from the higher-order mode of the circularly polarized wave received by the antenna unit, and the feeding unit An XPD calculation unit that calculates a cross polarization discrimination degree from the received sum signal calculated by the above-described calculation, and a null shift caused by the structure in the beam pattern of the antenna unit from the cross polarization discrimination degree calculated by the XPD calculation unit. A null shift correction value generation unit for calculating a quantity and determining a null shift correction value, and using the null shift correction value determined by the null shift correction value generation unit, the received sum signal and the A tracking signal correction unit that corrects a tracking error signal obtained from the signal difference signal, and a trajectory of a transmission source that transmits the circularly polarized wave received by the antenna unit based on the tracking error signal corrected by the tracking signal correction unit A tracking antenna device comprising an antenna control unit for calculating a position.   When the calculated cross-polarization discrimination is a value outside the range between the predetermined first upper limit value and the predetermined first lower limit value, the XPD calculation unit calculates The tracking according to claim 1 or 2, wherein a closer value of the predetermined first upper limit value and the predetermined first lower limit value is sent to the null shift correction value generation unit as the cross polarization discrimination degree. Antenna device.   When the generated null shift correction value is a value outside the range between the predetermined second upper limit value and the predetermined second lower limit value, the null shift correction value generation unit 4. The tracking antenna device according to claim 1, wherein a closer value of the predetermined second upper limit value and the predetermined second lower limit value is set as the null shift correction value. 5.   The tracking antenna device according to claim 4, wherein the null shift correction value generation unit sets the null shift correction value to 0 when the set null shift correction value is equal to or less than a predetermined value.   The tracking antenna device according to claim 4, wherein the tracking signal correction unit does not correct the tracking error signal when the null shift correction value set by the null shift correction value generation unit is a predetermined value or less.

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