WO2014045927A1 - Pulse compression radar - Google Patents

Pulse compression radar Download PDF

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Publication number
WO2014045927A1
WO2014045927A1 PCT/JP2013/074308 JP2013074308W WO2014045927A1 WO 2014045927 A1 WO2014045927 A1 WO 2014045927A1 JP 2013074308 W JP2013074308 W JP 2013074308W WO 2014045927 A1 WO2014045927 A1 WO 2014045927A1
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WO
WIPO (PCT)
Prior art keywords
signal
transmission signal
transmission
unit
correction data
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PCT/JP2013/074308
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French (fr)
Japanese (ja)
Inventor
泰暢 淺田
昭典 清水
英公 後藤
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古野電気株式会社
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Publication of WO2014045927A1 publication Critical patent/WO2014045927A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/282—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/26—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
    • G01S13/28—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4008—Means for monitoring or calibrating of parts of a radar system of transmitters

Definitions

  • the present invention relates to a pulse compression radar that performs predistortion processing.
  • a pulse compression radar that transmits a pulse having a predetermined width and performs a process of compressing the pulse width at the time of reception.
  • a signal amplified by an amplifying unit may be transmitted.
  • an amplifying unit power amplifier or the like
  • nonlinear distortion may occur.
  • a predistortion process is known.
  • correction data is obtained based on this distortion, and the transmission signal before amplification is corrected in advance so that the transmission signal has an ideal waveform after amplification by the amplification unit.
  • Patent Documents 1 to 3 disclose a transmission apparatus that performs this kind of predistortion processing.
  • Patent Document 1 discloses a configuration in which coefficients for calculating correction data are changed stepwise in order to quickly converge the correction data.
  • Patent Document 2 discloses a configuration in which an initial value of correction data is set in order to quickly converge the correction data.
  • Patent Document 3 discloses a configuration for calculating effective correction data based on acquired distortion.
  • the radar apparatus may switch and transmit a plurality of types of transmission signals as necessary. For example, a configuration using a transmission signal with a short pulse width for a short distance and a transmission signal with a long pulse width for a long distance, or a configuration for changing a transmission frequency to prevent interference between radar devices is known. Yes.
  • Patent Documents 1 to 3 are based on the premise that predistortion processing is performed in a configuration in which one type of transmission signal is transmitted. Therefore, the above-mentioned problems cannot be solved from these patent documents.
  • Patent Document 2 does not describe a circuit for predistortion or a circuit similar thereto. That is, Patent Document 2 does not provide a solution or suggestion for the above problem.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pulse compression radar capable of transmitting a plurality of types of transmission signals, in which distortion is appropriately removed even immediately after switching of transmission signals. It is to provide a configuration capable of transmitting a signal.
  • a pulse compression radar having the following configuration. That is, the pulse compression radar includes an ideal transmission signal output unit, a transmission signal amplification unit, an antenna, a signal feedback circuit, a correction data calculation unit, a correction data output unit, and a transmission signal correction unit.
  • the ideal transmission signal output unit outputs a transmission signal (transmission signal having an ideal waveform) before distortion occurs.
  • the transmission signal amplification unit amplifies and outputs an input transmission signal.
  • the antenna transmits a transmission signal output from the transmission signal amplification unit to the outside and receives a reflection signal of the transmission signal as a reception signal.
  • the signal feedback circuit feeds back the transmission signal output from the transmission signal amplifier as a feedback signal.
  • the correction data calculation unit obtains correction data for canceling distortion caused by amplification based on the feedback signal and the transmission signal output by the ideal transmission signal output unit.
  • the correction data output unit stores the correction data for a plurality of types of transmission signals, and outputs the correction data corresponding to the transmission signals transmitted by the antenna from the correction data.
  • the transmission signal correction unit corrects correction of the transmission signal output by the ideal transmission signal output unit based on the correction data selected by the correction data output unit.
  • the pulse compression radar can store a plurality of types of correction data, for example, when the transmission signal to be transmitted is switched, the correction data when the transmission signal was previously transmitted can be used. Therefore, since it is not necessary to obtain the correction data again, it is possible to transmit a transmission signal with less distortion immediately after switching the transmission signal.
  • the above-described pulse compression radar preferably has the following configuration. That is, the pulse compression radar includes a signal processing unit that obtains information on a target based on a reception signal received by the antenna. At least a part of the circuit that transmits the reception signal received by the antenna to the signal processing unit and the circuit that transmits the feedback signal to the correction data calculation unit are common to each other.
  • the two circuits can be shared, so that the circuit configuration can be simplified and the cost can be reduced by reducing the number of devices (mixers, etc.) that perform signal conversion and the like. Can be made.
  • the pulse compression radar includes a transmission signal output unit that stores a plurality of types of transmission signals corrected by the transmission signal correction unit and outputs a transmission signal selected from these transmission signals to the transmission signal amplification unit. Is preferred.
  • the corrected transmission signal can be transmitted without correcting the transmission signal using the correction data. Therefore, a transmission signal without distortion can be transmitted more quickly.
  • the ideal transmission signal output unit preferably stores a plurality of types of transmission signals before distortion occurs.
  • the antenna transmits a plurality of types of transmission signals while switching.
  • the pulse compression radar preferably includes a feedback signal storage unit that stores the feedback signal and continues to store the stored feedback signal until the correction data calculation unit obtains the correction data. .
  • the feedback signal storage unit continues to store the current feedback signal. Can continue to.
  • the correction data calculation unit compares the transmission signal output from the ideal transmission signal output unit with the feedback signal, and determines the correction data based on the comparison result. It is preferable to determine whether or not to recalculate.
  • the correction data is newly calculated and updated, and when the distortion of the transmission signal is small, control such as using the previously obtained correction data can be performed. . Therefore, the load on the correction data calculation unit can be reduced.
  • FIG. 1 is a block diagram of a radar apparatus according to an embodiment of the present invention.
  • the block diagram which shows the detailed structure of a correction coefficient output part and a transmission signal output part.
  • the graph which shows that the distortion of the transmission signal was eliminated by the predistortion process.
  • FIG. 1 is a block diagram of the radar apparatus 1.
  • the radar apparatus 1 of this embodiment is a type of pulse compression radar mounted on a ship, and transmits a transmission signal to the outside and analyzes the reflection signal (reception signal) to thereby detect the position and speed of a target. Can be detected.
  • the radar apparatus 1 alternately transmits a transmission signal having a short pulse width (short pulse signal) and a transmission signal having a long pulse width (long pulse signal).
  • a long pulse signal can clearly detect a distant target by compressing the pulse width at the time of reception.
  • the long pulse signal cannot detect a short-range target because the reflected signal reaches the radar device 1 while the signal is being transmitted. Therefore, the radar apparatus 1 transmits a short pulse signal in order to detect the target at a short distance.
  • the radar apparatus 1 is configured to perform the above-described predistortion processing for these two types of transmission signals.
  • a detailed configuration of the radar apparatus 1 will be described.
  • the radar apparatus 1 stores a transmission signal subjected to predistortion processing (detailed processing method will be described later) in the transmission signal output unit 13. And if the trigger pulse (transmission trigger) which determines the transmission timing of a transmission signal is produced
  • the DAC 14 converts the transmission signal output from the transmission signal output unit 13 from a digital signal to an analog signal, and outputs the converted transmission signal to the mixer 15.
  • the mixer 15 mixes this transmission signal with a local oscillator signal (local signal) output from the local oscillator 12. Thereby, the frequency of the transmission signal can be raised to the transmission frequency.
  • the mixer 15 outputs the transmission signal whose frequency is increased to the power amplifier 16.
  • the power amplifier 16 amplifies this transmission signal and transmits it from the antenna 10 to the outside via the circulator 11. Note that, when the transmission signal is amplified by the power amplifier 16, nonlinear distortion may occur in the transmission signal. However, in the present embodiment, since the transmission signal corrected in consideration of this distortion (predistortion processing is performed) is input to the power amplifier 16, radio waves without nonlinear distortion (less) are transmitted as the transmission signal. Sent.
  • the transmission signal output from the power amplifier 16 is also output to the switch 23 via the signal feedback circuit 42.
  • the transmission signal (feedback signal) output to the switch 23 is used for performing predistortion processing.
  • the antenna 10 is configured to transmit a transmission signal as described above, and to receive a reflected signal that has been reflected back from the target (echo source) as a reception signal.
  • the antenna 10 is configured to repeatedly transmit and receive radio waves while rotating in a horizontal plane at a predetermined rotation speed. With the above configuration, the horizontal plane can be scanned over 360 ° with the ship as the center, and the state of surrounding targets can be acquired.
  • the circulator 11 appropriately switches the signal path so that the high-energy transmission signal from the power amplifier 16 is not input to the reception-side circuit and the reception signal is appropriately input to the reception-side circuit. Can do.
  • the received signal passes through the circulator 11 and then passes through a limiter 21, an LNA (Low Noise Amplifier) 22, a switch 23, a mixer 24, and an ADC 25. Then, a radar image is generated by the radar image generation unit (signal processing unit) 26, and this radar image is displayed on the display unit 27.
  • the path through which the received signal passes may be referred to as a receiving circuit 41.
  • each device will be described.
  • the limiter 21 prevents a signal with an excessive signal level from flowing into the subsequent device. For example, the limiter 21 suppresses a signal having a signal level of a predetermined level or higher.
  • the LNA 22 performs processing for amplifying the signal level of the received signal. By passing through the LNA 22, the signal level of the weak received signal can be amplified to such an extent that subsequent processing can be performed.
  • the switch 23 receives the reception signal output from the LNA 22 and the feedback signal output from the power amplifier 16. The switch 23 outputs one of these signals to the mixer 24 at the subsequent stage.
  • the switching timing of the switch 23 depends on the transmission timing of the transmission signal of the radar apparatus 1 as shown in FIG. That is, the radar apparatus 1 switches between a transmission period for transmitting a transmission signal and a reception period for receiving a reflected signal at a predetermined timing, and does not perform transmission and reception in parallel.
  • the switch 23 outputs a feedback signal to the mixer 24 when the radar apparatus 1 is in the transmission period.
  • the switch 23 outputs a reception signal to the mixer 24 when the radar apparatus 1 is in the reception period.
  • the mixer 24 can reduce the frequency of the feedback signal or the reception signal by mixing the feedback signal or the reception signal and the local signal of the local oscillator 12.
  • the mixer 24 outputs a feedback signal or a reception signal whose frequency is lowered to the ADC 25.
  • the ADC 25 converts the feedback signal or the reception signal from an analog signal to a digital signal.
  • the ADC 25 outputs a feedback signal to the feedback signal storage unit 31 and outputs a reception signal to the radar image generation unit 26.
  • the radar image generation unit 26 performs pulse compression processing on the reception signal input from the ADC 25 in consideration of a transmission signal and the like, and creates a radar image based on the signal after the pulse compression processing. Specifically, the radar image generation unit 26 obtains the distance to the target based on the time difference between the timing at which the antenna 10 transmits the transmission signal and the timing at which the reflected signal is received. In addition, the radar image generation unit 26 acquires the direction of the target based on the rotation phase (direction) of the antenna 10. As described above, the radar image generation unit 26 generates a radar image.
  • the display unit 27 includes a liquid crystal display or the like, and can display a radar image created by the radar image generation unit 26.
  • the radar apparatus 1 includes a feedback signal storage unit 31, a signal adjustment unit 32, an ideal transmission signal output unit 33, a correction coefficient calculation unit (correction data calculation unit) 34, and a correction coefficient as a configuration for performing predistortion processing.
  • An output unit (correction data output unit) 35, a transmission signal correction unit 36, and a signal adjustment unit 37 are provided.
  • the feedback signal output from the switch 23 is input to the feedback signal storage unit 31 as described above.
  • the feedback signal is input to the feedback signal storage unit 31 every time the transmission signal is transmitted, the feedback signal is not updated while the correction coefficient calculation unit 34 and the like are performing the predistortion process.
  • the correction process using the feedback signal in use is continuously performed. be able to.
  • the signal adjustment unit 32 adjusts the feedback signal in order to appropriately perform the predistortion processing by the correction coefficient calculation unit 34 and the like.
  • the signal adjustment unit 32 performs, for example, processing for adjusting amplitude and phase in order to perform comparison.
  • the feedback signal after the signal adjustment by the signal adjustment unit 32 is output to the correction coefficient calculation unit 34.
  • the ideal transmission signal output unit 33 includes ideal transmission signal storage units 33a and 33b and an ideal transmission signal selection unit 33c.
  • the ideal transmission signal storage unit 33a stores a transmission signal (ideal waveform signal, ideal signal, reference signal) before distortion occurs for the short pulse signal.
  • the ideal transmission signal storage unit 33b stores an ideal signal of a long pulse signal.
  • the ideal transmission signal selection unit 33 c selects one of the two ideal signals and outputs the selected one to the correction coefficient calculation unit 34.
  • the ideal coefficient and the feedback signal after signal adjustment are input to the correction coefficient calculation unit 34.
  • the correction coefficient calculation unit 34 calculates a correction coefficient necessary for the predistortion process based on both signals.
  • the correction coefficient is a coefficient that quantitatively indicates the difference between the feedback signal and the ideal signal.
  • the correction coefficient calculation unit 34 calculates the correction coefficient h (n) by performing the calculation of the following equation (1).
  • x is an ideal signal
  • y is a feedback signal
  • ⁇ is a step size.
  • the step size is a coefficient that determines responsiveness (following performance).
  • the current correction coefficient h (n) is obtained based on the correction coefficient h (n ⁇ 1) obtained immediately before. That is, the correction coefficient calculation unit 34 updates the correction coefficient every moment in consideration of the past situation and the current situation.
  • step size how much the past situation is taken into consideration is determined by ⁇ (step size). If the step size is large, the current situation is emphasized, so that the difference between the ideal signal and the feedback signal can be corrected quickly, but the correction coefficient may diverge. On the other hand, if the step size is small, the correction coefficient is unlikely to diverge, but the difference between the ideal signal and the feedback signal cannot be corrected quickly.
  • the step size is determined in consideration of the above.
  • the correction coefficient output unit 35 stores correction coefficients for a plurality of types of signals. Specifically, as shown in FIG. 2A, the correction coefficient output unit 35 includes correction coefficient storage units 35a and 35b, and a correction coefficient selection unit 35c.
  • the correction coefficient storage unit 35a stores a correction coefficient for the short pulse signal. Therefore, when the feedback signal is a short pulse signal, the correction coefficient calculation unit 34 calculates a new correction coefficient using the correction coefficient stored in the correction coefficient storage unit 35a. Then, the correction coefficient calculation unit 34 stores (updates) the newly obtained correction coefficient in the correction coefficient storage unit 35a.
  • the correction coefficient storage unit 35b stores a correction coefficient for the long pulse signal. Therefore, as described above, the correction coefficient calculation unit 34 calculates a new correction coefficient using the correction coefficient stored in the correction coefficient storage unit 35b and the feedback signal (long pulse signal), and stores the correction coefficient in the correction coefficient storage unit 35b.
  • the correction coefficient selection unit 35 c reads the correction coefficient stored in one of the correction coefficient storage units 35 a and 35 b and outputs the correction coefficient to the transmission signal correction unit 36. For example, when the antenna 10 transmits a short pulse signal, the correction coefficient stored in the correction coefficient storage unit 35 a is read and output to the transmission signal correction unit 36.
  • the transmission signal correction unit 36 uses this correction coefficient to generate a transmission signal by adding a predetermined distortion to an ideal signal of a short pulse signal (a signal stored in the ideal transmission signal storage unit 33a) in advance.
  • the transmission signal generated by the transmission signal correction unit 36 is output to the signal adjustment unit 37.
  • the signal adjustment unit 37 adjusts the rate of the transmission signal and adjusts the amplitude in accordance with the DAC 14 at the subsequent stage.
  • the transmission signal adjusted by the signal adjustment unit 37 is output to the transmission signal output unit 13.
  • the transmission signal output unit 13 includes transmission signal storage units 13a and 13b and a transmission signal selection unit 13c.
  • the short pulse signal is stored in the transmission signal storage unit 13a.
  • the long pulse signal is stored in the transmission signal storage unit 13b.
  • the transmission signal selection unit 13c selects the short pulse signal or the long pulse signal according to the timing indicated by the transmission trigger as described above, and outputs it to the DAC 14. This transmission signal is amplified by the power amplifier 16 and then transmitted to the outside.
  • the transmission signal input to the power amplifier 16 is predistorted by the transmission signal correction unit 36 (distorted in advance). Therefore, when distortion is generated by the power amplifier 16, the distortions cancel each other, and the waveform of the transmission signal approximates an ideal signal.
  • Radar apparatus 1 performs predistortion processing as described above. Further, when a feedback signal is newly input, the correction coefficient calculation unit 34 and the like recalculates the correction coefficient based on the feedback signal. The transmission signal correction unit 36 corrects the transmission signal with the new correction coefficient. In this way, by repeating the predistortion process, distortion included in the transmission signal can be removed with higher accuracy.
  • the radar apparatus 1 of the present embodiment can simultaneously store both the correction coefficient for the short pulse signal and the correction coefficient for the long pulse signal. Therefore, since the correction coefficient can be continuously updated in parallel for both transmission signals, even if the transmission signal is switched every transmission, distortion of the transmission signal can be removed.
  • FIG. 4 schematically shows data indicating that the distortion of the transmission signal has been eliminated by the predistortion process.
  • FIG. 4A is a diagram comparing a signal obtained by pulse compression of a transmission signal that has not been subjected to predistortion processing, and a signal obtained by pulse compression of an ideal signal.
  • FIG. 4B is a diagram comparing a signal obtained by pulse-compressing a transmission signal that has been subjected to a predistortion process a sufficient number of times and a signal obtained by pulse-compressing an ideal signal.
  • the directivity is deteriorated due to the influence of distortion.
  • such deterioration is hardly found in the signal obtained by pulse-compressing the transmission signal in FIG. That is, the distortion of the transmission signal can be removed by the processing of this embodiment.
  • a mixer and a DAC for a radar image generation circuit are required in addition to a mixer and a DAC for a predistortion circuit.
  • a predistortion circuit and a radar image creation circuit are partially shared. Therefore, the mixer 15 and the DAC 14 can be shared by both circuits. Therefore, since the number of mixers and DACs can be reduced, the cost can be reduced.
  • the local oscillation signal of the local oscillator 12 needs to be transmitted to the three devices, so that the circuit configuration may be complicated.
  • control for reducing the load of calculation performed by the correction coefficient calculation unit 34 will be described. Since the calculation for calculating the correction coefficient is relatively heavy, the control can be performed as described below so that the correction coefficient is calculated only when necessary. This will be specifically described below.
  • the correction coefficient calculation unit 34 compares the ideal signal and the feedback signal before determining the correction coefficient, and determines whether or not both signals are approximate. If the correction coefficient calculation unit 34 determines that both signals are approximate, the correction coefficient is not calculated assuming that the distortion of the transmission signal has been sufficiently removed. In this case, the transmission signal correction unit 36 performs predistortion processing using the correction coefficient obtained previously.
  • the correction coefficient calculation unit 34 calculates the correction coefficient assuming that the distortion of the transmission signal is not sufficiently removed. In this case, the transmission signal correction unit 36 performs predistortion processing using the newly obtained correction coefficient.
  • the load on the correction coefficient calculation unit 34 can be reduced.
  • the signal comparison is not necessarily performed every time the feedback signal is input. For example, when both signals are approximated, the signals may be compared every predetermined number of times.
  • the radar apparatus 1 includes the ideal transmission signal output unit 33, the power amplifier 16, the antenna 10, the signal feedback circuit 42, the correction coefficient calculation unit 34, and the correction coefficient output unit. 35 and a transmission signal correction unit 36.
  • the ideal transmission signal output unit 33 outputs a transmission signal before distortion occurs.
  • the power amplifier 16 amplifies and outputs the input transmission signal.
  • the antenna 10 transmits the transmission signal output from the power amplifier 16 to the outside and receives a reflection signal of the transmission signal as a reception signal.
  • the signal feedback circuit 42 feeds back the transmission signal output from the power amplifier 16 as a feedback signal.
  • the correction coefficient calculation unit 34 Based on the feedback signal and the transmission signal output from the ideal transmission signal output unit 33, the correction coefficient calculation unit 34 obtains a correction coefficient for canceling distortion caused by amplification.
  • the correction coefficient output unit 35 stores correction coefficients for a plurality of types of transmission signals, and outputs correction coefficients corresponding to the transmission signals transmitted by the antenna from the correction coefficients.
  • the transmission signal correction unit 36 corrects the transmission signal input to the power amplifier 16 based on the correction coefficient selected by the correction coefficient output unit 35.
  • the radar apparatus 1 can store a plurality of types of correction coefficients, for example, when the transmission signal to be transmitted is switched, the correction coefficient when the transmission signal was previously transmitted can be used. Accordingly, since it is not necessary to obtain the correction coefficient again, it is possible to transmit a transmission signal with less distortion immediately after switching the transmission signal.
  • the transmission signals with different pulse widths shown in the above embodiment are mentioned. However, if different correction coefficients are required, they correspond to different transmission signals. For example, transmission signals having different transmission frequency changes (chirps) correspond to different types of transmission signals.
  • the radar apparatus is not limited to a configuration that transmits two types of transmission signals, and may be configured to transmit three or more types of transmission signals, for example. In this case, it is preferable that at least the number of correction coefficient storage units corresponding to the type of transmission signal is provided.
  • the signal amplifying unit is not limited to the power amplifier 16, and any device can be used as long as there is a possibility of distortion in the transmission signal.
  • the correction data calculation unit may be configured to calculate correction data necessary for performing the predistortion process, and calculates correction data by a method other than Equation (1). Also good. Further, the correction data calculation unit does not necessarily have to calculate the “coefficient”, and may be any configuration that calculates some data necessary for correction.
  • the storage target of the correction coefficient output unit 35 is not limited to the correction coefficient in the same manner.
  • the signal processing unit may be configured to obtain information on the target, and may be configured to obtain only the position of the target without generating the radar image.
  • the configuration shown in the block diagram of FIG. 1 is an example. If the configuration of the present invention is provided, addition, deletion, change of position, and the like of devices can be appropriately performed. For example, a configuration in which a high-pass filter is provided after the ADC 25 may be used. Further, a device that relays transmission / reception of correction coefficients may be provided between the correction coefficient calculation unit 34 and the correction coefficient storage units 35a and 35b. Similarly, a device that relays transmission of transmission signals may be provided between the signal adjustment unit 37 and the transmission signal storage units 13a and 13b.
  • the present invention is not limited to a marine radar device, but can be applied to a radar device mounted on another moving body such as an aircraft. Further, the present invention can be applied to a radar device for monitoring a route other than a use mounted on a moving body.

Abstract

[Problem] To provide a pulse compression radar capable of transmitting multiple types of transmission signals, wherein it is possible to transmit transmission signals in which distortions are appropriately removed even when the transmission signals were just switched. [Solution] A radar device (pulse compression radar) calculates a correction coefficient on the basis of a transmission signal before distortions occurred and a transmission signal (return signal) outputted from a power amplifier. The radar device is provided with a correction coefficient output unit (35) which stores the correction coefficients of multiple types of transmission signals and which outputs a correction coefficient corresponding to the transmission signal transmitted by an antenna. The correction coefficient outputted from the correction coefficient output unit (35) is outputted to a transmission signal correction unit (36). The transmission signal correction unit (36) corrects the transmission signal outputted from an ideal transmission signal output unit (33) by using the aforementioned correction coefficient by taking into consideration the distortions that occur during the amplification of the power amplifier.

Description

パルス圧縮レーダPulse compression radar
　本発明は、プリディストーション処理を行うパルス圧縮レーダに関する。 The present invention relates to a pulse compression radar that performs predistortion processing.
　従来から、所定の幅のパルスを送信し、受信時にパルス幅を圧縮する処理を行うパルス圧縮レーダが知られている。パルス圧縮レーダでは、増幅部（パワーアンプ等）によって増幅された信号を送信することがあるが、信号を増幅した場合、非線形の歪みが生じることがある。この非線形の歪みを補正する方法として、プリディストーション処理が知られている。 Conventionally, there is known a pulse compression radar that transmits a pulse having a predetermined width and performs a process of compressing the pulse width at the time of reception. In the pulse compression radar, a signal amplified by an amplifying unit (power amplifier or the like) may be transmitted. However, when the signal is amplified, nonlinear distortion may occur. As a method for correcting this non-linear distortion, a predistortion process is known.
　プリディストーション処理では、外部に送信される信号の一部を帰還させて非線形の歪みを取得し、この歪みを考慮して補正を行う。具体的には、この歪みに基づいて補正用データを求め、当該補正用データによって、送信信号が増幅部による増幅後に理想的な波形になるように、増幅前の送信信号を予め補正する。この処理を繰り返すことにより、補正用データは収束し、送信信号の歪みを効果的に除去することができる。 In the predistortion process, a part of the signal transmitted to the outside is fed back to obtain nonlinear distortion, and correction is performed in consideration of this distortion. Specifically, correction data is obtained based on this distortion, and the transmission signal before amplification is corrected in advance so that the transmission signal has an ideal waveform after amplification by the amplification unit. By repeating this process, the correction data converges and the distortion of the transmission signal can be effectively removed.
　特許文献１から３までは、この種のプリディストーション処理を行う送信装置を開示する。特許文献１では、補正用データを素早く収束させるために、補正用データを算出する際の係数を段階的に変化させる構成を開示する。特許文献２は、補正用データを素早く収束させるために、補正用データの初期値を設定する構成を開示する。特許文献３は、取得した歪みに基づいて効果的な補正用データを算出するための構成を開示する。 Patent Documents 1 to 3 disclose a transmission apparatus that performs this kind of predistortion processing. Patent Document 1 discloses a configuration in which coefficients for calculating correction data are changed stepwise in order to quickly converge the correction data. Patent Document 2 discloses a configuration in which an initial value of correction data is set in order to quickly converge the correction data. Patent Document 3 discloses a configuration for calculating effective correction data based on acquired distortion.
特開平６－３１０９４６号公報JP-A-6-310946 特開平６－３１０９４７号公報JP-A-6-310947 特開２００２－２２３１７１号公報JP 2002-223171 A
　ところで、レーダ装置においても、上記のプリディストーション処理は行われることがある。レーダ装置は、複数種類の送信信号を必要に応じて切り替えて送信する場合がある。例えば、近距離用にパルス幅の短い送信信号を用い、遠距離用にパルス幅の長い送信信号を用いる構成や、レーダ装置間の干渉を防止するために送信周波数を変える構成等が知られている。 By the way, the above-described predistortion processing may be performed also in the radar apparatus. The radar apparatus may switch and transmit a plurality of types of transmission signals as necessary. For example, a configuration using a transmission signal with a short pulse width for a short distance and a transmission signal with a long pulse width for a long distance, or a configuration for changing a transmission frequency to prevent interference between radar devices is known. Yes.
　この種のレーダ装置においてプリディストーション処理を行う場合、送信信号に応じて適切な補正用データは異なるため、送信信号を切り替えて直後は適切に歪みを補正できない。この点、特許文献１から３まではあくまで１種類の送信信号を送信する構成においてプリディストーション処理を行うことを前提としている。従って、これらの特許文献からは上記の課題を解決することができない。 When performing predistortion processing in this type of radar apparatus, the appropriate correction data differs depending on the transmission signal, so that the distortion cannot be corrected appropriately immediately after switching the transmission signal. In this regard, Patent Documents 1 to 3 are based on the premise that predistortion processing is performed in a configuration in which one type of transmission signal is transmitted. Therefore, the above-mentioned problems cannot be solved from these patent documents.
　なお、特許文献２の構成は、送信信号を補正する旨の記載もなく、送信側の回路は、送信信号ではなく較正用の信号を受信側の回路へ送信する構成である。従って、特許文献２のレーダ装置は、プリディストーション方式とは大きく異なる方式を採用している。従って、特許文献２には、当然プリディストーション用の回路又はそれに類似する回路も記載されていない。つまり、特許文献２は、上記の課題に対し、解決及びその示唆を与えるものではない。 Note that the configuration of Patent Document 2 is not described to correct the transmission signal, and the transmission side circuit transmits a calibration signal to the reception side circuit instead of the transmission signal. Therefore, the radar apparatus of Patent Document 2 employs a method that is significantly different from the predistortion method. Therefore, of course, Patent Document 2 does not describe a circuit for predistortion or a circuit similar thereto. That is, Patent Document 2 does not provide a solution or suggestion for the above problem.
　本発明は以上の事情に鑑みてされたものであり、その目的は、複数種類の送信信号を送信可能なパルス圧縮レーダにおいて、送信信号の切替直後であっても歪みが適切に除去された送信信号を送信可能な構成を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pulse compression radar capable of transmitting a plurality of types of transmission signals, in which distortion is appropriately removed even immediately after switching of transmission signals. It is to provide a configuration capable of transmitting a signal.
課題を解決するための手段及び効果Means and effects for solving the problems
　本発明の解決しようとする課題は以上の如くであり、次にこの課題を解決するための手段とその効果を説明する。 The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.
　本発明の観点によれば、以下の構成のパルス圧縮レーダが提供される。即ち、このパルス圧縮レーダは、理想送信信号出力部と、送信信号増幅部と、アンテナと、信号帰還回路と、補正用データ算出部と、補正用データ出力部と、送信信号補正部と、を備える。前記理想送信信号出力部は、歪みが生じる前の送信信号（理想的な波形の送信信号）を出力する。前記送信信号増幅部は、入力された送信信号を増幅して出力する。前記アンテナは、前記送信信号増幅部が出力した送信信号を外部に送信するとともに、当該送信信号の反射信号を受信信号として受信する。前記信号帰還回路は、前記送信信号増幅部が出力した送信信号を帰還信号として帰還させる。前記補正用データ算出部は、前記帰還信号と、前記理想送信信号出力部が出力した送信信号と、に基づいて、増幅により生じる歪みを打ち消すための補正用データを求める。前記補正用データ出力部は、複数種類の送信信号についての前記補正用データを記憶し、当該補正用データから、前記アンテナが送信する送信信号に対応する前記補正用データを出力する。前記送信信号補正部は、前記補正用データ出力部が選択した前記補正用データに基づいて、前記理想送信信号出力部が出力した送信信号を補正するを補正する。 According to an aspect of the present invention, a pulse compression radar having the following configuration is provided. That is, the pulse compression radar includes an ideal transmission signal output unit, a transmission signal amplification unit, an antenna, a signal feedback circuit, a correction data calculation unit, a correction data output unit, and a transmission signal correction unit. Prepare. The ideal transmission signal output unit outputs a transmission signal (transmission signal having an ideal waveform) before distortion occurs. The transmission signal amplification unit amplifies and outputs an input transmission signal. The antenna transmits a transmission signal output from the transmission signal amplification unit to the outside and receives a reflection signal of the transmission signal as a reception signal. The signal feedback circuit feeds back the transmission signal output from the transmission signal amplifier as a feedback signal. The correction data calculation unit obtains correction data for canceling distortion caused by amplification based on the feedback signal and the transmission signal output by the ideal transmission signal output unit. The correction data output unit stores the correction data for a plurality of types of transmission signals, and outputs the correction data corresponding to the transmission signals transmitted by the antenna from the correction data. The transmission signal correction unit corrects correction of the transmission signal output by the ideal transmission signal output unit based on the correction data selected by the correction data output unit.
　これにより、パルス圧縮レーダは、複数種類の補正用データを記憶可能であるため、例えば送信する送信信号を切り替えたときに、当該送信信号を以前に送信した時の補正用データを利用できる。従って、補正用データを求め直さなくて良いため、送信信号を切り替えた直後から歪みの少ない送信信号を送信することができる。 Thus, since the pulse compression radar can store a plurality of types of correction data, for example, when the transmission signal to be transmitted is switched, the correction data when the transmission signal was previously transmitted can be used. Therefore, since it is not necessary to obtain the correction data again, it is possible to transmit a transmission signal with less distortion immediately after switching the transmission signal.
　前記のパルス圧縮レーダにおいては、以下の構成とすることが好ましい。即ち、このパルス圧縮レーダは、前記アンテナが受信した受信信号に基づいて物標に関する情報を求める信号処理部を備える。そして、前記アンテナが受信した受信信号を前記信号処理部へ伝達する回路と、前記帰還信号を前記補正用データ算出部まで伝達する回路と、の少なくとも一部同士が共通である。 The above-described pulse compression radar preferably has the following configuration. That is, the pulse compression radar includes a signal processing unit that obtains information on a target based on a reception signal received by the antenna. At least a part of the circuit that transmits the reception signal received by the antenna to the signal processing unit and the circuit that transmits the feedback signal to the correction data calculation unit are common to each other.
　これにより、２つの回路の少なくとも一部同士を共通にすることができるので、回路構成を単純にすることができるとともに、信号の変換等を行う機器（ミキサ等）の個数を減らしてコストを低減させることができる。 As a result, at least a part of the two circuits can be shared, so that the circuit configuration can be simplified and the cost can be reduced by reducing the number of devices (mixers, etc.) that perform signal conversion and the like. Can be made.
　前記のパルス圧縮レーダにおいては、前記送信信号補正部により補正された送信信号を複数種類記憶し、これらの送信信号から選択した送信信号を前記送信信号増幅部へ出力する送信信号出力部を備えることが好ましい。 The pulse compression radar includes a transmission signal output unit that stores a plurality of types of transmission signals corrected by the transmission signal correction unit and outputs a transmission signal selected from these transmission signals to the transmission signal amplification unit. Is preferred.
　これにより、送信信号を切り替えた場合において、補正用データを用いて送信信号を補正することなく補正後の送信信号を送信できる。従って、一層素早く歪みの無い送信信号を送信することができる。 Thus, when the transmission signal is switched, the corrected transmission signal can be transmitted without correcting the transmission signal using the correction data. Therefore, a transmission signal without distortion can be transmitted more quickly.
　前記のパルス圧縮レーダにおいては、前記理想送信信号出力部は、歪みが生じる前の送信信号を複数種類記憶することが好ましい。 In the pulse compression radar, the ideal transmission signal output unit preferably stores a plurality of types of transmission signals before distortion occurs.
　これにより、予め複数種類の送信信号について歪みが生じる前の送信信号を記憶しておくことで、送信信号を切り替える度に理想送信信号を求めなくて良い。従って、処理量を軽減するとともに、送信信号の切替の直後から、補正用データの更新を行うことができる。 Thereby, it is not necessary to obtain an ideal transmission signal every time the transmission signal is switched, by storing the transmission signal before distortion occurs for a plurality of types of transmission signals in advance. Therefore, the processing amount can be reduced and the correction data can be updated immediately after the transmission signal is switched.
　前記のパルス圧縮レーダにおいては、前記アンテナは、複数種類の送信信号を切り替えながら送信することが好ましい。 In the pulse compression radar, it is preferable that the antenna transmits a plurality of types of transmission signals while switching.
　これにより、送信信号の切替直後であっても歪みを低減できるという上記の効果を一層有効に発揮させることができる。 Thereby, the above-described effect that distortion can be reduced even immediately after switching of the transmission signal can be more effectively exhibited.
　前記のパルス圧縮レーダにおいては、前記帰還信号を記憶するとともに、前記補正用データ算出部が前記補正用データを求めるまでは記憶中の前記帰還信号を記憶し続ける帰還信号記憶部を備えることが好ましい。 The pulse compression radar preferably includes a feedback signal storage unit that stores the feedback signal and continues to store the stored feedback signal until the correction data calculation unit obtains the correction data. .
　これにより、補正用データの算出が完了する前に新たな帰還信号が出力されてきた場合であっても、帰還信号記憶部は現在の帰還信号を記憶し続けるため、補正用データの算出を適切に継続することができる。 As a result, even when a new feedback signal is output before the calculation of the correction data is completed, the feedback signal storage unit continues to store the current feedback signal. Can continue to.
　前記のパルス圧縮レーダにおいては、前記補正用データ算出部は、前記理想送信信号出力部が出力した送信信号と、前記帰還信号と、を比較し、当該比較結果に基づいて、前記補正用データを再計算するか否かを決定することが好ましい。 In the pulse compression radar, the correction data calculation unit compares the transmission signal output from the ideal transmission signal output unit with the feedback signal, and determines the correction data based on the comparison result. It is preferable to determine whether or not to recalculate.
　これにより、例えば送信信号の歪みが大きい場合は補正用データを新たに算出して更新するとともに、送信信号の歪みが小さい場合は以前に求めた補正用データを利用する等の制御が可能となる。従って、補正用データ算出部の負荷を軽減することができる。 As a result, for example, when the distortion of the transmission signal is large, the correction data is newly calculated and updated, and when the distortion of the transmission signal is small, control such as using the previously obtained correction data can be performed. . Therefore, the load on the correction data calculation unit can be reduced.
本発明の一実施形態に係るレーダ装置のブロック図。1 is a block diagram of a radar apparatus according to an embodiment of the present invention. 補正係数出力部及び送信信号出力部の詳細な構成を示すブロック図。The block diagram which shows the detailed structure of a correction coefficient output part and a transmission signal output part. 送信トリガ、送信信号、及びスイッチのタイミングチャート。The transmission trigger, a transmission signal, and the timing chart of a switch. プリディストーション処理によって送信信号の歪みが解消したことを示すグラフ。The graph which shows that the distortion of the transmission signal was eliminated by the predistortion process.
　次に、図面を参照して本発明の実施の形態を説明する。図１は、レーダ装置１のブロック図である。 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the radar apparatus 1.
　本実施形態のレーダ装置１は、船舶に搭載されるタイプのパルス圧縮レーダであり、外部に送信信号を送信するとともに、その反射信号（受信信号）を解析することで、物標の位置や速度を検出することができる。 The radar apparatus 1 of this embodiment is a type of pulse compression radar mounted on a ship, and transmits a transmission signal to the outside and analyzes the reflection signal (reception signal) to thereby detect the position and speed of a target. Can be detected.
　図３に示すようにレーダ装置１は、パルス幅の短い送信信号（短パルス信号）と、パルス幅の長い送信信号（長パルス信号）と、を交互に送信する。長パルス信号は、受信時にパルス幅を圧縮することで、遠方の物標を明確に検出することができる。しかし、長パルス信号は、信号を送信している途中で反射信号がレーダ装置１に到達するため、近距離の物標を探知できない。そのため、レーダ装置１は、この近距離の物標を探知するために、短パルス信号を送信する。また、レーダ装置１は、この２種類の送信信号について、上述のプリディストーション処理を行う構成である。以下、レーダ装置１の詳細な構成について説明する。 As shown in FIG. 3, the radar apparatus 1 alternately transmits a transmission signal having a short pulse width (short pulse signal) and a transmission signal having a long pulse width (long pulse signal). A long pulse signal can clearly detect a distant target by compressing the pulse width at the time of reception. However, the long pulse signal cannot detect a short-range target because the reflected signal reaches the radar device 1 while the signal is being transmitted. Therefore, the radar apparatus 1 transmits a short pulse signal in order to detect the target at a short distance. The radar apparatus 1 is configured to perform the above-described predistortion processing for these two types of transmission signals. Hereinafter, a detailed configuration of the radar apparatus 1 will be described.
　レーダ装置１は、プリディストーション処理（詳細な処理方法は後述）を行った送信信号を送信信号出力部１３に記憶する。そして、送信信号の送信タイミングを定めるトリガパルス（送信トリガ）が生成されると、送信信号出力部１３は、送信信号を出力する（図３を参照）。この送信信号は、図１に示すように、ＤＡＣ１４、ミキサ１５、パワーアンプ（送信信号増幅部）１６、サーキュレータ１１を経由して、アンテナ１０から外部へ送信される。 The radar apparatus 1 stores a transmission signal subjected to predistortion processing (detailed processing method will be described later) in the transmission signal output unit 13. And if the trigger pulse (transmission trigger) which determines the transmission timing of a transmission signal is produced | generated, the transmission signal output part 13 will output a transmission signal (refer FIG. 3). As shown in FIG. 1, this transmission signal is transmitted from the antenna 10 to the outside via the DAC 14, the mixer 15, the power amplifier (transmission signal amplification unit) 16, and the circulator 11.
　ＤＡＣ１４は、送信信号出力部１３が出力する送信信号を、デジタル信号からアナログ信号に変換し、変換後の送信信号をミキサ１５へ出力する。 The DAC 14 converts the transmission signal output from the transmission signal output unit 13 from a digital signal to an analog signal, and outputs the converted transmission signal to the mixer 15.
　ミキサ１５は、この送信信号を、局部発振器１２が出力する局部発振器信号（局発信号）と混合する。これにより、送信信号の周波数を送信周波数まで引き上げることができる。ミキサ１５は、周波数が引き上げられた送信信号をパワーアンプ１６へ出力する。 The mixer 15 mixes this transmission signal with a local oscillator signal (local signal) output from the local oscillator 12. Thereby, the frequency of the transmission signal can be raised to the transmission frequency. The mixer 15 outputs the transmission signal whose frequency is increased to the power amplifier 16.
　パワーアンプ１６は、この送信信号を増幅し、サーキュレータ１１を介して、アンテナ１０から外部へ送信する。なお、パワーアンプ１６によって送信信号が増幅されることで、送信信号に非線形の歪みが生じ得る。しかし、本実施形態ではこの歪みを考慮して補正された（プリディストーション処理が行われた）送信信号がパワーアンプ１６へ入力されているため、非線形の歪みの無い（少ない）電波が送信信号として送信される。 The power amplifier 16 amplifies this transmission signal and transmits it from the antenna 10 to the outside via the circulator 11. Note that, when the transmission signal is amplified by the power amplifier 16, nonlinear distortion may occur in the transmission signal. However, in the present embodiment, since the transmission signal corrected in consideration of this distortion (predistortion processing is performed) is input to the power amplifier 16, radio waves without nonlinear distortion (less) are transmitted as the transmission signal. Sent.
　なお、パワーアンプ１６が出力する送信信号は、信号帰還回路４２を介して、スイッチ２３にも出力される。スイッチ２３へ出力された送信信号（帰還信号）は、プリディストーション処理を行うために利用される。 The transmission signal output from the power amplifier 16 is also output to the switch 23 via the signal feedback circuit 42. The transmission signal (feedback signal) output to the switch 23 is used for performing predistortion processing.
　アンテナ１０は、上記のように送信信号を送信し、この送信信号が物標（エコー源）に反射して戻ってきた反射信号を受信信号として受信するように構成されている。また、アンテナ１０は、所定の回転速度で水平面内を回転しながら、電波の送受信を繰り返し行うように構成されている。以上の構成で、自船を中心として水平面内を３６０°にわたってスキャンし、周囲の物標の様子を取得することができる。 The antenna 10 is configured to transmit a transmission signal as described above, and to receive a reflected signal that has been reflected back from the target (echo source) as a reception signal. The antenna 10 is configured to repeatedly transmit and receive radio waves while rotating in a horizontal plane at a predetermined rotation speed. With the above configuration, the horizontal plane can be scanned over 360 ° with the ship as the center, and the state of surrounding targets can be acquired.
　サーキュレータ１１は、パワーアンプ１６からの高エネルギーの送信信号が受信側の回路に入力されないように、かつ、受信信号が受信側の回路に適切に入力されるように、信号の経路を適宜切り替えることができる。 The circulator 11 appropriately switches the signal path so that the high-energy transmission signal from the power amplifier 16 is not input to the reception-side circuit and the reception signal is appropriately input to the reception-side circuit. Can do.
　次に、アンテナ１０が受信した受信信号を処理する構成について説明する。受信信号は、サーキュレータ１１を通過した後に、リミッタ２１、ＬＮＡ（Ｌｏｗ　Ｎｏｉｓｅ　Ａｍｐｌｉｆｉｅｒ）２２、スイッチ２３、ミキサ２４、ＡＤＣ２５を通過する。そして、レーダ映像作成部（信号処理部）２６によってレーダ映像が作成され、このレーダ映像が表示部２７に表示される。なお、以下の説明では、この受信信号が通る経路を受信回路４１と称することがある。以下、それぞれの機器について説明する。 Next, a configuration for processing a received signal received by the antenna 10 will be described. The received signal passes through the circulator 11 and then passes through a limiter 21, an LNA (Low Noise Amplifier) 22, a switch 23, a mixer 24, and an ADC 25. Then, a radar image is generated by the radar image generation unit (signal processing unit) 26, and this radar image is displayed on the display unit 27. In the following description, the path through which the received signal passes may be referred to as a receiving circuit 41. Hereinafter, each device will be described.
　リミッタ２１は、過大な信号レベルの信号が後段の機器に流れ込むことを防止する。リミッタ２１は、例えば信号レベルが所定以上の信号を抑圧する。 The limiter 21 prevents a signal with an excessive signal level from flowing into the subsequent device. For example, the limiter 21 suppresses a signal having a signal level of a predetermined level or higher.
　ＬＮＡ２２は、受信信号の信号レベルを増幅する処理を行う。このＬＮＡ２２を経由することで、微弱な受信信号の信号レベルを後段の処理が行える程度まで増幅することができる。 The LNA 22 performs processing for amplifying the signal level of the received signal. By passing through the LNA 22, the signal level of the weak received signal can be amplified to such an extent that subsequent processing can be performed.
　スイッチ２３には、ＬＮＡ２２から出力される受信信号と、パワーアンプ１６から出力される前記帰還信号と、が入力される。スイッチ２３は、これらの信号のうち一方を後段のミキサ２４へ出力する。 The switch 23 receives the reception signal output from the LNA 22 and the feedback signal output from the power amplifier 16. The switch 23 outputs one of these signals to the mixer 24 at the subsequent stage.
　スイッチ２３の切替タイミングは、図３に示すように、レーダ装置１の送信信号の送信タイミングに依存している。つまり、レーダ装置１は、送信信号を送信する送信期間と、反射信号を受信する受信期間と、を所定のタイミングで切り替えており、送信と受信とを並行して行わない。そして、スイッチ２３は、レーダ装置１が送信期間である場合、帰還信号をミキサ２４へ出力する。一方、スイッチ２３は、レーダ装置１が受信期間である場合、受信信号をミキサ２４へ出力する。これにより、帰還信号と受信信号が同じ経路を通る場合であっても、信号同士が混合されることを防止できる。 The switching timing of the switch 23 depends on the transmission timing of the transmission signal of the radar apparatus 1 as shown in FIG. That is, the radar apparatus 1 switches between a transmission period for transmitting a transmission signal and a reception period for receiving a reflected signal at a predetermined timing, and does not perform transmission and reception in parallel. The switch 23 outputs a feedback signal to the mixer 24 when the radar apparatus 1 is in the transmission period. On the other hand, the switch 23 outputs a reception signal to the mixer 24 when the radar apparatus 1 is in the reception period. As a result, even when the feedback signal and the received signal pass through the same path, the signals can be prevented from being mixed.
　ミキサ２４は、ミキサ１５と同様に、帰還信号又は受信信号と、局部発振器１２の局発信号と、を混合することで、帰還信号又は受信信号の周波数を引き下げることができる。ミキサ２４は、周波数が引き下げられた帰還信号又は受信信号をＡＤＣ２５へ出力する。 Similar to the mixer 15, the mixer 24 can reduce the frequency of the feedback signal or the reception signal by mixing the feedback signal or the reception signal and the local signal of the local oscillator 12. The mixer 24 outputs a feedback signal or a reception signal whose frequency is lowered to the ADC 25.
　ＡＤＣ２５は、帰還信号又は受信信号を、アナログ信号からデジタル信号へ変換する。ＡＤＣ２５は、帰還信号を帰還信号記憶部３１へ出力し、受信信号をレーダ映像生成部２６へ出力する。 The ADC 25 converts the feedback signal or the reception signal from an analog signal to a digital signal. The ADC 25 outputs a feedback signal to the feedback signal storage unit 31 and outputs a reception signal to the radar image generation unit 26.
　レーダ映像生成部２６は、ＡＤＣ２５から入力された受信信号に送信信号等を考慮してパルス圧縮処理を行い、パルス圧縮処理後の信号に基づいて、レーダ映像を作成する。具体的には、レーダ映像生成部２６は、アンテナ１０が送信信号を送信したタイミングと、反射信号を受信したタイミングと、の時間差に基づいて物標までの距離を求める。また、レーダ映像生成部２６は、アンテナ１０の回転位相（向き）に基づいて当該物標の方向を取得する。以上のようにして、レーダ映像生成部２６は、レーダ映像を生成する。 The radar image generation unit 26 performs pulse compression processing on the reception signal input from the ADC 25 in consideration of a transmission signal and the like, and creates a radar image based on the signal after the pulse compression processing. Specifically, the radar image generation unit 26 obtains the distance to the target based on the time difference between the timing at which the antenna 10 transmits the transmission signal and the timing at which the reflected signal is received. In addition, the radar image generation unit 26 acquires the direction of the target based on the rotation phase (direction) of the antenna 10. As described above, the radar image generation unit 26 generates a radar image.
　表示部２７は、液晶ディスプレイ等を備えており、レーダ映像生成部２６が作成したレーダ映像を表示することができる。 The display unit 27 includes a liquid crystal display or the like, and can display a radar image created by the radar image generation unit 26.
　次に、プリディストーション処理を行う構成について説明する。 Next, a configuration for performing predistortion processing will be described.
　レーダ装置１は、プリディストーション処理を行う構成として、帰還信号記憶部３１と、信号調整部３２と、理想送信信号出力部３３と、補正係数算出部（補正用データ算出部）３４と、補正係数出力部（補正用データ出力部）３５と、送信信号補正部３６と、信号調整部３７と、を備えている。 The radar apparatus 1 includes a feedback signal storage unit 31, a signal adjustment unit 32, an ideal transmission signal output unit 33, a correction coefficient calculation unit (correction data calculation unit) 34, and a correction coefficient as a configuration for performing predistortion processing. An output unit (correction data output unit) 35, a transmission signal correction unit 36, and a signal adjustment unit 37 are provided.
　帰還信号記憶部３１には、前述のように、スイッチ２３が出力した帰還信号が入力される。帰還信号記憶部３１には、送信信号の送信毎に帰還信号が入力されるが、補正係数算出部３４等がプリディストーション処理を行っている間は、帰還信号を更新しないものとする。これにより、ある帰還信号を用いたプリディストーション処理が完了する前に次の帰還信号が帰還信号記憶部３１に入力された場合であっても、利用中の帰還信号による補正処理を継続して行うことができる。 The feedback signal output from the switch 23 is input to the feedback signal storage unit 31 as described above. Although the feedback signal is input to the feedback signal storage unit 31 every time the transmission signal is transmitted, the feedback signal is not updated while the correction coefficient calculation unit 34 and the like are performing the predistortion process. Thereby, even when the next feedback signal is input to the feedback signal storage unit 31 before the predistortion process using a certain feedback signal is completed, the correction process using the feedback signal in use is continuously performed. be able to.
　信号調整部３２は、補正係数算出部３４等によるプリディストーション処理を適切に行うために、帰還信号を調整する。信号調整部３２は、例えば、比較を行うために振幅や位相を調整する処理等を行う。信号調整部３２による信号調整後の帰還信号は、補正係数算出部３４へ出力される。 The signal adjustment unit 32 adjusts the feedback signal in order to appropriately perform the predistortion processing by the correction coefficient calculation unit 34 and the like. The signal adjustment unit 32 performs, for example, processing for adjusting amplitude and phase in order to perform comparison. The feedback signal after the signal adjustment by the signal adjustment unit 32 is output to the correction coefficient calculation unit 34.
　理想送信信号出力部３３は、図２（ｂ）に示すように、理想送信信号記憶部３３ａ，３３ｂと、理想送信信号選択部３３ｃと、を備えている。理想送信信号記憶部３３ａは、短パルス信号について、歪みが生じる前の送信信号（理想的な波形の信号、理想信号、リファレンス信号）を記憶している。理想送信信号記憶部３３ｂは、長パルス信号の理想信号を記憶している。理想送信信号選択部３３ｃは、この２つの理想信号のうち何れか一方を選択し、補正係数算出部３４へ出力する。 As shown in FIG. 2B, the ideal transmission signal output unit 33 includes ideal transmission signal storage units 33a and 33b and an ideal transmission signal selection unit 33c. The ideal transmission signal storage unit 33a stores a transmission signal (ideal waveform signal, ideal signal, reference signal) before distortion occurs for the short pulse signal. The ideal transmission signal storage unit 33b stores an ideal signal of a long pulse signal. The ideal transmission signal selection unit 33 c selects one of the two ideal signals and outputs the selected one to the correction coefficient calculation unit 34.
　補正係数算出部３４には、この理想信号と、信号調整後の帰還信号と、が入力される。補正係数算出部３４は、両信号に基づいて、プリディストーション処理に必要な補正係数を算出する。補正係数とは、帰還信号と理想信号との差を定量的に示す係数である。本実施形態において補正係数算出部３４は、以下の式（１）の演算を行うことにより、補正係数ｈ（ｎ）を算出する。
Figure JPOXMLDOC01-appb-M000001
 The ideal coefficient and the feedback signal after signal adjustment are input to the correction coefficient calculation unit 34. The correction coefficient calculation unit 34 calculates a correction coefficient necessary for the predistortion process based on both signals. The correction coefficient is a coefficient that quantitatively indicates the difference between the feedback signal and the ideal signal. In the present embodiment, the correction coefficient calculation unit 34 calculates the correction coefficient h (n) by performing the calculation of the following equation (1).
Figure JPOXMLDOC01-appb-M000001
　ここで、ｘは理想信号であり、ｙは帰還信号であり、μはステップサイズである。ステップサイズは、応答性（追従性）を定める係数である。また、現在の補正係数ｈ（ｎ）は、直前に求めた補正係数ｈ（ｎ－１）に基づいて求められる。つまり、補正係数算出部３４は、過去の状況と現在の状況とを加味して、補正係数を刻々と更新していく。 Where x is an ideal signal, y is a feedback signal, and μ is a step size. The step size is a coefficient that determines responsiveness (following performance). The current correction coefficient h (n) is obtained based on the correction coefficient h (n−1) obtained immediately before. That is, the correction coefficient calculation unit 34 updates the correction coefficient every moment in consideration of the past situation and the current situation.
　ここで、過去の状況をどれだけ加味するかは、μ（ステップサイズ）によって決定される。ステップサイズが大きいと現在の状況を重視するため、理想信号と帰還信号との差を素早く補正することができるが、補正係数が発散してしまうことがある。一方、ステップサイズが小さいと補正係数が発散する可能性は低いが、理想信号と帰還信号との差を素早く補正することができない。ステップサイズは、以上のことを考慮して定められる。 Here, how much the past situation is taken into consideration is determined by μ (step size). If the step size is large, the current situation is emphasized, so that the difference between the ideal signal and the feedback signal can be corrected quickly, but the correction coefficient may diverge. On the other hand, if the step size is small, the correction coefficient is unlikely to diverge, but the difference between the ideal signal and the feedback signal cannot be corrected quickly. The step size is determined in consideration of the above.
　補正係数出力部３５は、複数種類の信号の補正係数を記憶している。具体的には、補正係数出力部３５は、図２（ａ）に示すように、補正係数記憶部３５ａ，３５ｂと、補正係数選択部３５ｃと、を備えている。 The correction coefficient output unit 35 stores correction coefficients for a plurality of types of signals. Specifically, as shown in FIG. 2A, the correction coefficient output unit 35 includes correction coefficient storage units 35a and 35b, and a correction coefficient selection unit 35c.
　補正係数記憶部３５ａは、短パルス信号の補正係数を記憶している。従って、補正係数算出部３４は、帰還信号が短パルス信号である場合は、補正係数記憶部３５ａの記憶する補正係数を用いて、新たな補正係数を算出する。そして、補正係数算出部３４は、新たに求めた補正係数を補正係数記憶部３５ａに記憶する（更新する）。 The correction coefficient storage unit 35a stores a correction coefficient for the short pulse signal. Therefore, when the feedback signal is a short pulse signal, the correction coefficient calculation unit 34 calculates a new correction coefficient using the correction coefficient stored in the correction coefficient storage unit 35a. Then, the correction coefficient calculation unit 34 stores (updates) the newly obtained correction coefficient in the correction coefficient storage unit 35a.
　補正係数記憶部３５ｂは、長パルス信号の補正係数を記憶している。従って、補正係数算出部３４は、上記と同様に、補正係数記憶部３５ｂの記憶する補正係数と帰還信号（長パルス信号）を用いて、新たな補正係数を算出し、補正係数記憶部３５ｂに記憶する。 The correction coefficient storage unit 35b stores a correction coefficient for the long pulse signal. Therefore, as described above, the correction coefficient calculation unit 34 calculates a new correction coefficient using the correction coefficient stored in the correction coefficient storage unit 35b and the feedback signal (long pulse signal), and stores the correction coefficient in the correction coefficient storage unit 35b. Remember.
　補正係数選択部３５ｃは、補正係数記憶部３５ａ，３５ｂのうち一方に記憶された補正係数を読み出し、送信信号補正部３６へ出力する。例えば、アンテナ１０が短パルス信号を送信する場合、補正係数記憶部３５ａに記憶された補正係数を読み出し、送信信号補正部３６へ出力する。 The correction coefficient selection unit 35 c reads the correction coefficient stored in one of the correction coefficient storage units 35 a and 35 b and outputs the correction coefficient to the transmission signal correction unit 36. For example, when the antenna 10 transmits a short pulse signal, the correction coefficient stored in the correction coefficient storage unit 35 a is read and output to the transmission signal correction unit 36.
　送信信号補正部３６は、この補正係数を用いて、短パルス信号の理想信号（理想送信信号記憶部３３ａに記憶される信号）に予め所定の歪みを加えて送信信号を生成する。送信信号補正部３６によって生成された送信信号は、信号調整部３７に出力される。 The transmission signal correction unit 36 uses this correction coefficient to generate a transmission signal by adding a predetermined distortion to an ideal signal of a short pulse signal (a signal stored in the ideal transmission signal storage unit 33a) in advance. The transmission signal generated by the transmission signal correction unit 36 is output to the signal adjustment unit 37.
　信号調整部３７は、後段のＤＡＣ１４に合わせて送信信号のレートを調整したり、振幅を調整したりする。信号調整部３７が調整した送信信号は送信信号出力部１３へ出力される。 The signal adjustment unit 37 adjusts the rate of the transmission signal and adjusts the amplitude in accordance with the DAC 14 at the subsequent stage. The transmission signal adjusted by the signal adjustment unit 37 is output to the transmission signal output unit 13.
　送信信号出力部１３は、図２（ｃ）に示すように、送信信号記憶部１３ａ，１３ｂと、送信信号選択部１３ｃと、を備えている。信号調整部３７から出力された信号が短パルス信号であった場合、当該短パルス信号は、送信信号記憶部１３ａに記憶される。一方、信号調整部３７から出力された信号が長パルス信号であった場合、当該長パルス信号は、送信信号記憶部１３ｂに記憶される。送信信号選択部１３ｃは、前述のように送信トリガが示すタイミングに応じて、短パルス信号又は長パルス信号を選択してＤＡＣ１４へ出力する。この送信信号は、パワーアンプ１６によって増幅された後に外部へ送信される。 As shown in FIG. 2C, the transmission signal output unit 13 includes transmission signal storage units 13a and 13b and a transmission signal selection unit 13c. When the signal output from the signal adjustment unit 37 is a short pulse signal, the short pulse signal is stored in the transmission signal storage unit 13a. On the other hand, when the signal output from the signal adjustment unit 37 is a long pulse signal, the long pulse signal is stored in the transmission signal storage unit 13b. The transmission signal selection unit 13c selects the short pulse signal or the long pulse signal according to the timing indicated by the transmission trigger as described above, and outputs it to the DAC 14. This transmission signal is amplified by the power amplifier 16 and then transmitted to the outside.
　ここで、パワーアンプ１６に入力される送信信号は、送信信号補正部３６によってプリディストーション処理が行われている（予め歪められている）。従って、パワーアンプ１６により歪みが発生することで、歪み同士が打ち消し合い、送信信号の波形が理想信号に近似する。 Here, the transmission signal input to the power amplifier 16 is predistorted by the transmission signal correction unit 36 (distorted in advance). Therefore, when distortion is generated by the power amplifier 16, the distortions cancel each other, and the waveform of the transmission signal approximates an ideal signal.
　レーダ装置１は、以上のようにして、プリディストーション処理を行う。また、補正係数算出部３４等は、新たに帰還信号が入力されると、当該帰還信号に基づいて補正係数を求め直す。送信信号補正部３６は、この新たな補正係数によって送信信号を補正する。このように、プリディストーション処理が繰り返されることで、送信信号に含まれる歪みをより高精度に除去できる。 Radar apparatus 1 performs predistortion processing as described above. Further, when a feedback signal is newly input, the correction coefficient calculation unit 34 and the like recalculates the correction coefficient based on the feedback signal. The transmission signal correction unit 36 corrects the transmission signal with the new correction coefficient. In this way, by repeating the predistortion process, distortion included in the transmission signal can be removed with higher accuracy.
　従来のように１種類しか補正係数を記憶しない構成では、送信信号の切替直後に再び補正係数を算出する必要がある。従って、送信毎に送信信号を切り替えるレーダ装置では送信信号の歪みを除去することが困難であった。この点、本実施形態のレーダ装置１は、短パルス信号の補正係数と、長パルス信号の補正係数と、の両方を同時に記憶することができる。従って、両方の送信信号について並行して補正係数を更新し続けることができるので、送信毎に送信信号を切り替える構成であっても、送信信号の歪みを除去することができる。 In the conventional configuration in which only one type of correction coefficient is stored, it is necessary to calculate the correction coefficient again immediately after the transmission signal is switched. Therefore, it is difficult to remove the distortion of the transmission signal in the radar apparatus that switches the transmission signal for each transmission. In this regard, the radar apparatus 1 of the present embodiment can simultaneously store both the correction coefficient for the short pulse signal and the correction coefficient for the long pulse signal. Therefore, since the correction coefficient can be continuously updated in parallel for both transmission signals, even if the transmission signal is switched every transmission, distortion of the transmission signal can be removed.
　図４には、プリディストーション処理によって送信信号の歪みが解消したことを示すデータが概略的に示されている。図４（ａ）は、プリディストーション処理を行っていない送信信号をパルス圧縮した信号と、理想信号をパルス圧縮した信号と、を比較する図である。図４（ｂ）は、プリディストーション処理を十分な回数行った送信信号をパルス圧縮した信号と、理想信号をパルス圧縮した信号と、を比較する図である。図４（ａ）の送信信号をパルス圧縮した信号には、歪みの影響による指向性の劣化が発生している。これに対し、図４（ｂ）の送信信号をパルス圧縮した信号にはこのような劣化が殆ど見当たらない。つまり、本実施形態の処理により、送信信号の歪みを除去することができる。 FIG. 4 schematically shows data indicating that the distortion of the transmission signal has been eliminated by the predistortion process. FIG. 4A is a diagram comparing a signal obtained by pulse compression of a transmission signal that has not been subjected to predistortion processing, and a signal obtained by pulse compression of an ideal signal. FIG. 4B is a diagram comparing a signal obtained by pulse-compressing a transmission signal that has been subjected to a predistortion process a sufficient number of times and a signal obtained by pulse-compressing an ideal signal. In the signal obtained by pulse compression of the transmission signal in FIG. 4A, the directivity is deteriorated due to the influence of distortion. On the other hand, such deterioration is hardly found in the signal obtained by pulse-compressing the transmission signal in FIG. That is, the distortion of the transmission signal can be removed by the processing of this embodiment.
　次に、信号帰還回路４２を備えることによる利点について説明する。 Next, advantages of providing the signal feedback circuit 42 will be described.
　信号帰還回路４２がない構成では、プリディストーション用の回路のためのミキサ及びＤＡＣに加え、レーダ映像作成用の回路のためのミキサ及びＤＡＣが必要となる。これに対し、本実施形態では、プリディストーション用の回路と、レーダ映像作成用の回路と、が一部共通する構成である。そのため、両回路でミキサ１５及びＤＡＣ１４を共通にすることができる。従って、ミキサ及びＤＡＣの数を減らすことができるので、コストを低減することができる。 In the configuration without the signal feedback circuit 42, a mixer and a DAC for a radar image generation circuit are required in addition to a mixer and a DAC for a predistortion circuit. On the other hand, in the present embodiment, a predistortion circuit and a radar image creation circuit are partially shared. Therefore, the mixer 15 and the DAC 14 can be shared by both circuits. Therefore, since the number of mixers and DACs can be reduced, the cost can be reduced.
　また、信号帰還回路４２がない構成では、局部発振器１２の局発信号を３つの機器に送信する必要があるので、回路構成が複雑になる可能性がある。これに対し、本実施形態では、局部発振器１２の局発信号を２つの機器に送信するだけで良いので、レーダ装置１のスペースを有効に活用して配線を行うことができ、回路構成を簡単することができる。 Further, in the configuration without the signal feedback circuit 42, the local oscillation signal of the local oscillator 12 needs to be transmitted to the three devices, so that the circuit configuration may be complicated. On the other hand, in this embodiment, it is only necessary to transmit the local oscillation signal of the local oscillator 12 to the two devices, so that the wiring of the radar device 1 can be effectively utilized and the circuit configuration can be simplified. can do.
　次に、補正係数算出部３４で行われる演算の負荷を軽減するための制御について説明する。補正係数を算出する演算は比較的負荷が大きいため、以下のように制御を行って、必要なときにのみ補正係数が算出される構成にすることができる。以下、具体的に説明する。 Next, control for reducing the load of calculation performed by the correction coefficient calculation unit 34 will be described. Since the calculation for calculating the correction coefficient is relatively heavy, the control can be performed as described below so that the correction coefficient is calculated only when necessary. This will be specifically described below.
　この制御を行う場合、補正係数算出部３４は、補正係数を算出する前に理想信号と帰還信号を比較して両信号が近似しているか否かを判定する。そして、補正係数算出部３４は、両信号が近似していると判定した場合、送信信号の歪みは十分に除去されているものとして、補正係数を算出しない。この場合、送信信号補正部３６は、以前に求めた補正係数を用いてプリディストーション処理を行う。 When performing this control, the correction coefficient calculation unit 34 compares the ideal signal and the feedback signal before determining the correction coefficient, and determines whether or not both signals are approximate. If the correction coefficient calculation unit 34 determines that both signals are approximate, the correction coefficient is not calculated assuming that the distortion of the transmission signal has been sufficiently removed. In this case, the transmission signal correction unit 36 performs predistortion processing using the correction coefficient obtained previously.
　一方、補正係数算出部３４は、両信号が近似していないと判定した場合、送信信号の歪みが十分に除去されていないとして、補正係数を算出する。この場合、送信信号補正部３６は、新たに求めた補正係数を用いてプリディストーション処理を行う。 On the other hand, when it is determined that the two signals are not approximate, the correction coefficient calculation unit 34 calculates the correction coefficient assuming that the distortion of the transmission signal is not sufficiently removed. In this case, the transmission signal correction unit 36 performs predistortion processing using the newly obtained correction coefficient.
　以上のような制御を行うことで、補正係数算出部３４の負荷を軽減できる。なお、信号の比較は、帰還信号が入力される毎に行う必要は必ずしもなく、例えば両信号が近似している場合は、所定回数毎に信号を比較しても良い。 By performing the control as described above, the load on the correction coefficient calculation unit 34 can be reduced. Note that the signal comparison is not necessarily performed every time the feedback signal is input. For example, when both signals are approximated, the signals may be compared every predetermined number of times.
　以上に説明したように、本実施形態のレーダ装置１は、理想送信信号出力部３３と、パワーアンプ１６と、アンテナ１０と、信号帰還回路４２と、補正係数算出部３４と、補正係数出力部３５と、送信信号補正部３６と、を備える。理想送信信号出力部３３は、歪みが生じる前の送信信号を出力する。パワーアンプ１６は、入力された送信信号を増幅して出力する。アンテナ１０は、パワーアンプ１６が出力した送信信号を外部に送信するとともに、当該送信信号の反射信号を受信信号として受信する。信号帰還回路４２は、パワーアンプ１６が出力した送信信号を帰還信号として帰還させる。補正係数算出部３４は、帰還信号と、理想送信信号出力部３３が出力した送信信号と、に基づいて、増幅により生じる歪みを打ち消すための補正係数を求める。補正係数出力部３５は、複数種類の送信信号についての補正係数を記憶し、当該補正係数から、アンテナが送信する送信信号に対応する補正係数を出力する。送信信号補正部３６は、補正係数出力部３５が選択した補正係数に基づいて、パワーアンプ１６に入力される送信信号を補正する。 As described above, the radar apparatus 1 according to the present embodiment includes the ideal transmission signal output unit 33, the power amplifier 16, the antenna 10, the signal feedback circuit 42, the correction coefficient calculation unit 34, and the correction coefficient output unit. 35 and a transmission signal correction unit 36. The ideal transmission signal output unit 33 outputs a transmission signal before distortion occurs. The power amplifier 16 amplifies and outputs the input transmission signal. The antenna 10 transmits the transmission signal output from the power amplifier 16 to the outside and receives a reflection signal of the transmission signal as a reception signal. The signal feedback circuit 42 feeds back the transmission signal output from the power amplifier 16 as a feedback signal. Based on the feedback signal and the transmission signal output from the ideal transmission signal output unit 33, the correction coefficient calculation unit 34 obtains a correction coefficient for canceling distortion caused by amplification. The correction coefficient output unit 35 stores correction coefficients for a plurality of types of transmission signals, and outputs correction coefficients corresponding to the transmission signals transmitted by the antenna from the correction coefficients. The transmission signal correction unit 36 corrects the transmission signal input to the power amplifier 16 based on the correction coefficient selected by the correction coefficient output unit 35.
　これにより、レーダ装置１は、複数種類の補正係数を記憶可能であるため、例えば送信する送信信号を切り替えたときに、当該送信信号を以前に送信した時の補正係数を利用できる。従って、補正係数を求め直さなくて良いため、送信信号を切り替えた直後から歪みの少ない送信信号を送信することができる。 Thereby, since the radar apparatus 1 can store a plurality of types of correction coefficients, for example, when the transmission signal to be transmitted is switched, the correction coefficient when the transmission signal was previously transmitted can be used. Accordingly, since it is not necessary to obtain the correction coefficient again, it is possible to transmit a transmission signal with less distortion immediately after switching the transmission signal.
　以上に本発明の好適な実施の形態を説明したが、上記の構成は例えば以下のように変更することができる。 Although a preferred embodiment of the present invention has been described above, the above configuration can be modified as follows, for example.
　異なる種類の送信信号の例として、上記実施形態で示したパルス幅の違う送信信号を挙げたが、異なる補正係数が必要であれば異なる送信信号に該当するものとする。例えば、送信周波数の変化態様（チャープ）が異なる送信信号も異なる種類の送信信号に該当する。 As an example of different types of transmission signals, the transmission signals with different pulse widths shown in the above embodiment are mentioned. However, if different correction coefficients are required, they correspond to different transmission signals. For example, transmission signals having different transmission frequency changes (chirps) correspond to different types of transmission signals.
　上記実施形態では、２種類の送信信号を交互に送信する構成であるが、ユーザの指示や状況に応じて送信信号を切り替える構成であっても良い。また、レーダ装置は、２種類の送信信号を送信する構成に限られず、例えば３種類以上の送信信号を送信する構成であっても良い。この場合、補正係数記憶部は、少なくとも送信信号の種類に応じた個数は設けられることが好ましい。 In the above-described embodiment, two types of transmission signals are alternately transmitted. However, a configuration in which transmission signals are switched according to a user instruction or situation may be used. The radar apparatus is not limited to a configuration that transmits two types of transmission signals, and may be configured to transmit three or more types of transmission signals, for example. In this case, it is preferable that at least the number of correction coefficient storage units corresponding to the type of transmission signal is provided.
　信号増幅部はパワーアンプ１６に限られず、送信信号に歪みが生じる可能性があれば、任意の機器を使用することができる。 The signal amplifying unit is not limited to the power amplifier 16, and any device can be used as long as there is a possibility of distortion in the transmission signal.
　補正用データ算出部（補正係数算出部３４）は、プリディストーション処理を行う際に必要な補正用データを算出する構成であれば良く、式（１）以外の方法で補正用データを算出しても良い。また、補正用データ算出部は、「係数」を算出する必要は必ずしもなく、補正に必要な何らかのデータを算出する構成であれば良い。なお、補正係数出力部３５の記憶対象も同様に補正係数に限られない。 The correction data calculation unit (correction coefficient calculation unit 34) may be configured to calculate correction data necessary for performing the predistortion process, and calculates correction data by a method other than Equation (1). Also good. Further, the correction data calculation unit does not necessarily have to calculate the “coefficient”, and may be any configuration that calculates some data necessary for correction. The storage target of the correction coefficient output unit 35 is not limited to the correction coefficient in the same manner.
　信号処理部（レーダ映像生成部２６）は、物標に関する情報を求める構成であれば良く、レーダ映像まで生成せずに物標の位置のみを求める構成であっても良い。 The signal processing unit (radar image generation unit 26) may be configured to obtain information on the target, and may be configured to obtain only the position of the target without generating the radar image.
　図１のブロック図で示した構成は一例であり、本発明の構成を備えていれば、機器の追加、削除、位置の変更等を適宜行うことができる。例えば、ＡＤＣ２５の後段にハイパスフィルタを備える構成であっても良い。また、補正係数算出部３４と、補正係数記憶部３５ａ，３５ｂとの間に、補正係数の送受信を中継する機器を設けても良い。同様に、信号調整部３７と、送信信号記憶部１３ａ，１３ｂとの間に、送信信号の送信を中継する機器を設けても良い。 The configuration shown in the block diagram of FIG. 1 is an example. If the configuration of the present invention is provided, addition, deletion, change of position, and the like of devices can be appropriately performed. For example, a configuration in which a high-pass filter is provided after the ADC 25 may be used. Further, a device that relays transmission / reception of correction coefficients may be provided between the correction coefficient calculation unit 34 and the correction coefficient storage units 35a and 35b. Similarly, a device that relays transmission of transmission signals may be provided between the signal adjustment unit 37 and the transmission signal storage units 13a and 13b.
　本発明は、船舶用のレーダ装置に限られず、航空機等の他の移動体に搭載されるレーダ装置に適用することができる。また、移動体に搭載される用途以外にも、航路監視用のレーダ装置にも適用することができる。 The present invention is not limited to a marine radar device, but can be applied to a radar device mounted on another moving body such as an aircraft. Further, the present invention can be applied to a radar device for monitoring a route other than a use mounted on a moving body.
　１　レーダ装置（パルス圧縮レーダ）
　１３　送信信号出力部
　１３ａ，１３ｂ　送信信号記憶部
　１３ｃ　送信信号選択部
　１６　パワーアンプ（送信信号増幅部）
　２１　リミッタ
　２２　ＬＮＡ
　２３　スイッチ
　２４　ミキサ
　２５　ＡＤＣ
　３１　帰還信号記憶部
　３３　理想送信信号記憶部
　３４　補正係数算出部（補正用データ算出部）
　３５　補正係数出力部（補正用データ出力部）
　３５ａ，３５ｂ　補正係数記憶部
　３５ｃ　補正係数選択部
　３６　送信信号補正部
　４１　受信回路
　４２　信号帰還回路 1 Radar equipment (pulse compression radar)
13 Transmission signal output unit 13a, 13b Transmission signal storage unit 13c Transmission signal selection unit 16 Power amplifier (transmission signal amplification unit)
21 Limiter 22 LNA
23 switch 24 mixer 25 ADC
31 Feedback signal storage unit 33 Ideal transmission signal storage unit 34 Correction coefficient calculation unit (correction data calculation unit)
35 Correction coefficient output section (correction data output section)
35a, 35b Correction coefficient storage unit 35c Correction coefficient selection unit 36 Transmission signal correction unit 41 Reception circuit 42 Signal feedback circuit

Claims (7)

  1. 　歪みが生じる前の送信信号を出力する理想送信信号出力部と、
    　入力された送信信号を増幅して出力する送信信号増幅部と、
    　前記送信信号増幅部が出力した送信信号を外部に送信するとともに、当該送信信号の反射信号を受信信号として受信するアンテナと、
    　前記送信信号増幅部が出力した送信信号を帰還信号として帰還させる信号帰還回路と、
    　前記帰還信号と、前記理想送信信号出力部が出力した送信信号と、に基づいて、増幅により生じる歪みを打ち消すための補正用データを求める補正用データ算出部と、
    　複数種類の送信信号についての前記補正用データを記憶し、当該補正用データから、前記アンテナが送信する送信信号に対応する前記補正用データを出力する補正用データ出力部と、
    　前記補正用データ出力部が選択した前記補正用データに基づいて、前記理想送信信号出力部が出力した送信信号を補正する送信信号補正部と、
    を備えることを特徴とするパルス圧縮レーダ。     An ideal transmission signal output unit that outputs a transmission signal before distortion occurs;
    A transmission signal amplifier for amplifying and outputting the input transmission signal; and
    An antenna that transmits the transmission signal output from the transmission signal amplification unit to the outside and receives a reflection signal of the transmission signal as a reception signal;
    A signal feedback circuit that feeds back a transmission signal output from the transmission signal amplifier as a feedback signal;
    Based on the feedback signal and the transmission signal output by the ideal transmission signal output unit, a correction data calculation unit for obtaining correction data for canceling distortion caused by amplification,
    A correction data output unit that stores the correction data for a plurality of types of transmission signals, and outputs the correction data corresponding to the transmission signals transmitted by the antenna from the correction data;
    A transmission signal correction unit that corrects the transmission signal output by the ideal transmission signal output unit based on the correction data selected by the correction data output unit;
    A pulse compression radar comprising:
  2. 　請求項１に記載のパルス圧縮レーダであって、
    　前記アンテナが受信した受信信号に基づいて物標に関する情報を求める信号処理部を備え、
    　前記アンテナが受信した受信信号を前記信号処理部へ伝達する回路と、前記帰還信号を前記補正用データ算出部まで伝達する回路と、の少なくとも一部同士が共通であることを特徴とするパルス圧縮レーダ。     The pulse compression radar according to claim 1,
    A signal processing unit for obtaining information on a target based on a received signal received by the antenna;
    Pulse compression characterized in that at least a part of a circuit for transmitting a reception signal received by the antenna to the signal processing unit and a circuit for transmitting the feedback signal to the correction data calculation unit are common to each other Radar.
  3. 　請求項１又は２に記載のパルス圧縮レーダであって、
    　前記送信信号補正部により補正された送信信号を複数種類記憶し、これらの送信信号から選択した送信信号を前記送信信号増幅部へ出力する送信信号出力部を備えることを特徴とするパルス圧縮レーダ。     The pulse compression radar according to claim 1 or 2,
    A pulse compression radar comprising a transmission signal output unit that stores a plurality of types of transmission signals corrected by the transmission signal correction unit and outputs a transmission signal selected from these transmission signals to the transmission signal amplification unit.
  4. 　請求項１から３までの何れか一項に記載のパルス圧縮レーダであって、
    　前記理想送信信号出力部は、歪みが生じる前の送信信号を複数種類記憶することを特徴とするパルス圧縮レーダ。     The pulse compression radar according to any one of claims 1 to 3,
    The ideal transmission signal output unit stores a plurality of types of transmission signals before distortion occurs.
  5. 　請求項１から４までの何れか一項に記載のパルス圧縮レーダであって、
    　前記アンテナは、複数種類の送信信号を切り替えながら送信することを特徴とするパルス圧縮レーダ。     The pulse compression radar according to any one of claims 1 to 4,
    The pulse compression radar, wherein the antenna transmits a plurality of types of transmission signals while switching.
  6. 　請求項１から５までの何れか一項に記載のパルス圧縮レーダであって、
    　前記帰還信号を記憶するとともに、前記補正用データ算出部が前記補正用データを求めるまでは記憶中の前記帰還信号を記憶し続ける帰還信号記憶部を備えることを特徴とするパルス圧縮レーダ。     The pulse compression radar according to any one of claims 1 to 5,
    A pulse compression radar comprising: a feedback signal storage unit that stores the feedback signal and continues to store the stored feedback signal until the correction data calculation unit obtains the correction data.
  7. 　請求項１から６までの何れか一項に記載のパルス圧縮レーダであって、
    　前記補正用データ算出部は、前記理想送信信号出力部が出力した送信信号と、前記帰還信号と、を比較し、当該比較結果に基づいて、前記補正用データを再計算するか否かを決定することを特徴とするパルス圧縮レーダ。     The pulse compression radar according to any one of claims 1 to 6,
    The correction data calculation unit compares the transmission signal output from the ideal transmission signal output unit with the feedback signal and determines whether to recalculate the correction data based on the comparison result. A pulse compression radar characterized by:
PCT/JP2013/074308 2012-09-19 2013-09-10 Pulse compression radar WO2014045927A1 (en)

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