JP2616397B2 - Low threshold tracking receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for tracking and tracking an antenna of a flying object, and more particularly to a signal type ｛(Binary Phase Shift keying, BPSK), (Quadr) having no carrier wave.
iphase Phase Shift keying (QPSK) The present invention relates to detection of an error voltage for tracking and tracking an antenna of a flying object that transmits data with a modulated wave or the like.

[0002]

2. Description of the Related Art In general, a cross-correlation method is used to detect an error voltage for capturing and tracking an antenna of a flying object that transmits data in a signal format having no carrier wave, such as a BPSK or QPSK modulated wave. Adopted.

[0003] This cross-correlation method means that a sum signal (A + B + C + D) of four horns (A, B, C, D) connected to an antenna and a difference signal ｛(A + B)-(C +
D)｝ is detected, the difference signal is synchronously detected based on the sum signal, and an error signal in two directions, X and Y, which are orthogonal to each other, is detected.

FIG. 3 is a block diagram showing an example of a conventional antenna tracking receiver (particularly in the case of tracking in the form of a signal having no carrier wave) used for tracking a flying object such as a rocket or an artificial satellite.

As shown in FIG. 3, an antenna tracking receiver includes an automatic gain control (AGC) circuit 50 and a detection circuit 60.
And The AGC circuit 50 receives bandpass filters 1 and 2 respectively connected to input terminals S1 and S2 for inputting a difference signal IF signal and a sum signal IF signal (hereinafter simply referred to as difference signal and sum signal), respectively. AGC amplifiers 3 and 4
, Bandpass filter 11, and asynchronous AM detector (DET)
12, a low-pass filter 13, and an amplifier 14.

[0006] The detection circuit 60 includes a limiter 7 and a synchronous AM.
Detector (AM DET) 5 and π / 2 phase shifter (π / 2)
8, a synchronous AM detector (AM DET) 6, and a pair of amplifiers 9 and 10.

In this conventional antenna tracking receiver, a difference signal and a sum signal are respectively input to input terminals S1 and S2 from an antenna (not shown), and band-limited by band-pass filters 1 and 2, respectively. To enter. On the other hand, the sum signal passes through the band-pass filters 11, DET12, low-pass filters 13, 14, and AMP 14, and forms a sum signal AGC loop fed back to the AGC amplifiers 3, 4, so that the input levels of the sum signal and the difference signal are kept constant. To keep. The difference signals whose input level is constant by the sum signal AGC are respectively input to synchronous AM detectors (AMDET) 5 and 6 for detecting orthogonal angle error voltages. Next, the sum signal is amplitude-limited by a limiter 7 for synchronous detection with the difference signal, and then distributed as a reference signal for error voltage detection corresponding to the tracking of the antenna. The reference signal is a Y error voltage detection reference signal shifted by (π / 2) 8.

The synchronous AM detectors 5 and 6 perform synchronous AM detection of the difference signal and the above-mentioned X and Y error voltage detection reference signals, and output the respective X error voltage and Y error voltage. The signals are amplified at 9 and 10, and output to an antenna driving circuit (not shown) as an X error signal and a Y error signal.

[0009]

In this conventional tracking receiver, since a cross-correlation method, that is, a method of synchronously detecting a difference signal based on a sum signal as described above, is employed, a synchronous AM method is employed. Sum signal C / N at detector input
= + 10 dB (N: noise power in terms of the main lobe bandwidth of the signal spectrum) was the detection limit of the error signal.

And actually, when capturing a flying object,
Usually, the antenna beam and the flying object are displaced, and the receiving level is reduced by an amount corresponding to the pointing loss, and a very critical capturing operation is performed. Therefore, the operation limit is C / N = A tracking receiver having an angle error detector operating up to about 0 dB has been required.

Therefore, one technical problem of the present invention is that it becomes possible to capture an operation threshold level of about 0 dB as compared with the conventional art, and it is possible to follow a decrease in the threshold level.
And to provide a capability for low thresholds add tail receiver.

Further, another technical problem of the present invention is that the operation limit can be improved to about 0 dB in C / N conversion at the preceding stage of the synchronous detector, and the lowering of the threshold level can be followed.
And to provide a possible low thresholds add tail receiver.

[0013]

SUMMARY OF THE INVENTION A low threshold of the present invention.
The de add tail receiver, in the tracking receiver for use in an antenna acquisition and tracking have bandpass filters 10 to 20 percent of the bandwidth of the main lobe of the signal wave, switching the reception level of the tracking signal
At the same time as adding a tracking difference signal.
Gain control with the AGC voltage for signal
AGC circuit for maintaining the difference between the AGC circuit and the output of the AGC circuit
A detection circuit for detecting a tracking error signal by synchronous detection;
A tracking sum signal of the AGC circuit connected to the detection circuit;
Tracking error signal of the detection circuit accompanying a decrease in the reception level of
By compensating for the output drop, the tracking error signal output drop is reduced.
By suppressing the threshold level of the tracking receiver,
And a correction circuit for lowering the bell .

[0014] In the low thresholds add tail receiver of the present invention, in the Teisu Resshoru de add tail receiver, said correction circuit is characterized in that it comprises a correction ROM for digital signal processing.

Furthermore, the low thresholds add tail receiver of the present invention, chromatic wherein the low thresholds add tail receiver, means for generating a pilot signal for detecting the C / N of the input signal to the sum signal stage The correction circuit performs a required band limitation from the composite signal of the pilot signal and the sum signal, extracts a pilot signal, configures a pilot signal AGC circuit with the pilot signal, and configures the correction RO circuit.
M is characterized in that the output of the pilot signal AGC circuit is input.

[0016] In the low thresholds add tail receiver of the present invention, in the tracking receiver for use in an antenna acquisition and tracking, and generates a pilot signal for detecting the C / N of the input signal to the sum signal system IF signal stage Means for combining the pilot signal and the IF signal to form a sum signal AGC loop, performing a required band limitation from the combined IF signal, extracting a pilot signal, and An AGC loop is formed, C / N of the sum signal is detected, and a decrease in the detector output corresponding to the AGC voltage of the sum signal is corrected by a correction ROM.

[0017]

EXAMPLES will be described with reference to the drawings with the embodiments of the present invention.

[0018] FIG. 1 is a diagram showing a configuration of a low threshold <br/> Scholl de add tail receiver according to a first embodiment of the present invention. Parts having the same functions as those in the conventional example of FIG. 3 are denoted by the same reference numerals.
As shown in Figure 1, low thresholds add tail receiver, A
It includes a GC circuit 50, a detection circuit 60, and a correction circuit 70.

The AGC circuit 50 includes AGC amplifiers 3 and 4
, Bandpass filter 11, and asynchronous AM detector (DET)
12, a low-pass filter 13, and an amplifier (AMP) 1
4 is provided.

The detection circuit 60 includes a band rejection filter 15, a limiter 7, and a synchronous AM detector (AM).
DET) 5, 6, a π / 2 phase shifter (π / 2) 8, and gain control amplifiers 9, 10.

The correction circuit 70 includes the bandpass filter 16 and A
A GC amplifier 17, an asynchronous detector (DET) 18, a low-pass filter 19, an AMP 20, an A / D converter (A / D) 21, and a correction read-only memory (Read
Only memory, ROM) 22 and a D / A converter (D / A
A) 23.

[0022] In this low thresholds add tail receiver, the difference signal system IF signal (difference signal) to the input terminal S1 from the antenna, the sum signal system IF signal (sum signal) is input to the input terminal S2, respectively, the band Bands are limited by filters 1 and 2, respectively, and input to AGC amplifiers 3 and 4 of AGC circuit 50. Here, the sum signal is combined with the pilot signal from the pilot oscillator (OSC) 24 outside the signal band before the input to the AGC amplifier 4, and the sum signal from the AGC amplifier 4 is combined with a band filter constituting a sum signal AGC circuit. 11,
Asynchronous AM detector (DET) 12, low-pass filter 1
3, and returns to the AGC amplifiers 3 and 4 via the AMP 14. The sum signal AGC makes the input levels of the sum signal and the difference signal constant. The difference signals whose input level is constant by the sum signal AGC are input to AM DETs 5 and 6 for detecting orthogonal angle error voltages. Next, in order to perform synchronous detection (cross-correlation method) with the difference signal based on the sum signal, a band rejection filter 15 for removing the pilot signal from the sum signal is used. After the restriction, the signal is distributed as a reference signal for detecting an error voltage corresponding to the tracking of the antenna, and a reference signal for detecting an X error voltage and (π / 2)
The AM DETs 5 and 6 perform synchronous AM detection as the Y error voltage detection reference signals shifted by 8 and detect the respective angle error voltages, and the gain control amplifiers 9 and 10 respectively.
Is amplified by

The operation of the correction circuit 70 is as follows. From the sum signal of the AGC amplifier 4 combined with the pilot signal, only the pilot signal is extracted by the bandpass filter 16, and the pilot signal is used to extract the AGC amplifier 1
7, DET 18, low-pass filter 19 and amplifier 20
A pilot AGC circuit is configured to detect the input level C / N, convert the pilot AGC voltage into a digital signal by the A / D 21, and write the digital signal into the correction ROM 22 according to the input signal. Next, the correction value corresponding to the input signal of the correction ROM 20 is stored in the D / A
The gain control amplifiers 9 and 10 are controlled by a correction analog voltage value output to the D / A 23 and output from the D / A 23. The gain control amplifiers 9 and 10 have the corrected Xerro
The r and Yerror signals are output to the illustrated antenna drive circuit.

FIG. 2 is a functional block diagram of a low thread <br/> Sshoru de add tail receiver according to a second embodiment of the present invention. As shown in Figure 2, low thresholds add tail receiver according to the second embodiment, from those of the prior art shown in FIG. 3, the AGC circuit 50, together with an amplifier 25, AMP
Correction circuit 7 which receives a part of sum signal AGC from
It differs in having 0. The correction circuit 70 has an A / D converter (A / D) 21, a correction ROM 22, and a D / A converter (D / A) 23.

In the second embodiment, a bandpass filter 11 having a band of 10 to 20% of the main lobe of a signal wave is inserted in a stage preceding the envelope detector 12 for detecting the power of the sum signal IF signal. , AGC operation using a synchronous AM detector (AM
DET) It is improved to about 0 dB in terms of the pre-stage conversion of 5 and 6, and the decrease of the detector output corresponding to the AGC voltage is
That is, the operation limit is improved by compensating for a decrease in detection sensitivity due to a decrease in C / N.

The correction circuit 70 converts the AGC voltage to A /
The signal is converted into a digital signal by D21, a correction value is calculated from the signal by the correction ROM 22, and the correction value is converted again into an analog signal by the D / A converter. The gain is controlled.

[0027]

As described above, according to the present invention, the operation threshold level is C / N = 0d as compared with the prior art.
It is possible to provide a capturable become low thresholds add tail receiver to approximately B.

Further , in the present invention , the pilot AGC detects the C / N of the sum signal, and the lowering of the output of the detection circuit corresponding to the AGC voltage of the sum signal, that is, the lowering of the detection sensitivity due to the C / N drop. it is possible to provide a low thresholds add tail receiver can improve the operating limits to approximately 0dB in the preceding stage of the C / N conversion synchronous detection by using the correction ROM for the.

[Brief description of the drawings]

1 is a block diagram of a low thresholds additionally <br/> tail receiver according to a first embodiment of the present invention.

2 is a block diagram of a low thresholds additionally <br/> tail receiver according to a second embodiment of the present invention.

FIG. 3 is a block diagram of an example of the related art.

[Explanation of symbols]

 S1, S2 Input terminals 1, 2, 11, 16 Bandpass filter 3, 4, 17 AGC amplifier 5, 6 Synchronous AM detector (AM DET) 7 Limiter 8 π / 2 phase shifter (π / 2) 9, 10 Gain Control amplifier 12, 18 Asynchronous AM detector (DET) 13, 19 Low-pass filter 14, 20 Amplifier (AMP) 21 A / D converter (A / D) 22 Correction read-only memory (ROM) 23 D / A converter (D / A) 24 Pilot signal oscillator (OSC)

Claims (4)

(57) [Claims] 1. A tracking receiver used for antenna capture and tracking, which has a band filter for a band of 10 to 20% of a main lobe of a signal wave, and performs switching of a reception level of a tracking signal.
A tracking difference signal is added to the signal at the same time as keeping it at a constant level.
Gain control with AGC voltage, relative level difference between sum and difference signals
AGC circuit that maintains
A detection circuit for detecting a tracking error signal by detection;
The AGC circuit is connected to a detection circuit and receives the tracking sum signal of the AGC circuit.
Tracking error signal output of the detection circuit accompanying a decrease in signal level
Of the tracking error signal output.
The threshold level of the tracking receiver
Low thread <br/> Scholl de add tail receiver; and a correction circuit for lowering. 2. A according to claim 1, wherein the low thresholds add tail receiver, said correction circuit, it additionally low Suresshi <br/> ® le de characterized that a correction for ROM to the digital signal processing Tail receiver. 3. The method of claim 2 low thresholds add tail receiver according comprises means for generating a pilot signal for detecting the C / N of the input signal to the sum signal stage, said correction circuit the pilot A required band limitation is performed from a combined signal of the signal and the sum signal to extract a pilot signal,
Constitute a pilot signal AGC circuit in the pilot signal, the correction ROM is low Suresshi <br/> ® le de add tail receiver characterized in that it receives the output of the pilot signal AGC circuit. 4. A tracking receiver used for capturing and tracking an antenna, comprising means for generating a pilot signal for detecting a C / N of an input signal in an IF signal stage of a sum signal system, wherein the pilot signal and the IF signal are combined. To form a sum signal AGC loop, perform a required band limitation from the synthesized IF signal, extract a pilot signal, form a pilot signal AGC loop with the pilot signal, and perform C / N
Of performs detection, low thresholds add tail receiver and correcting by the correction ROM a decreased amount of the detector output corresponding to the AGC voltage of the sum signal.