CN106788509B - Microwave approach receiver captures single frames scanning signal auto gain control method - Google Patents

Abstract

The present invention provides a kind of microwave approach receivers to capture single frames scanning signal auto gain control method, initial channel gain control value and ideal output waveforms peak value are set first, AD samplers sample microwave landing sweep waveform, and demodulate generation baseband waveform, available waveforms are identified after low-pass filtering, judge whether have complete waveform, if not having, then pass through top characteristic or lower along characteristic deduction complete waveform, passes through complete waveform and ideal ruler waveform peak value difference is rounded control AGC gain amount.The present invention establishes channel gain control access using single frames scanning beam, substantially increases channel AGC and establishes efficiency, so that more microwave landing scanning signals are used for the resolving of signal angle information；The principle of the invention is simple, and algorithm meets the requirement of real-time of practical application, has stronger engineer application.

Description

Microwave approach receiver captures single frames scanning signal auto gain control method

Technical field

The present invention relates to microwave landing system airboarne receivers, more particularly to a kind of microwave landing system airboarne receiver Linear passageway automatic growth control.

Background technique

Microwave landing system (MLS) is a kind of landing approach of air-derived data, and microwave landing airborne equipment receives micro- Navigation information in the wave landing system area of coverage, by obtaining the Angle Position data in space where aircraft after processing, be aircraft into Close and offer instruction of landing.

Microwave landing airboarne receiver when carrying out signal processing using linear passageway, adjusted respectively using channel by timesharing Mutually with the demodulation process of amplitude-modulated signal, the processing of amplitude-modulated signal is after phase-modulated signal, and phase modulation circuit provides amplitude-modulated signal Time zero, modulation circuit receives the amplitude size of signal by scanning, to adjust optimal AGC control parameter, Jin Ershi Now to the measurement of scanning signal and to the calculating of angle.The data rate of microwave landing high speed orientation mode is 39Hz, previous Microwave landing system airboarne receiver linear passageway automatic growth control using coarse search add essence search combine by the way of realize, such as Shown in Fig. 1.

It is 0 that initial gain controlling value, which is arranged, passes through one frame microwave landing scanning beam signal of AD port processing and demodulation, solution Signal passes through low-pass filtering after tune, be scanned difference between signal maximum and ideal scan signal value output whether Difference between coarse search stage within the scope of 10dB and scanning signal maximum value and ideal scan signal value output whether The smart search phase within the scope of 1dB, in the coarse search stage with the controlling value of 10dB increasing amount adjustment AGC voltage, the smart search phase with 1dB increasing amount adjustment AGC voltage controling value, by coarse search and essence search after, into scanning beam tracking phase, then judge with Whether track is lost, and does not lose, then continues to track；Lose, then come back to the incipient stage restart modulate AGC voltage control.

The previous automatic gain method using multiframe sweep waveform, which adjusts an AGC, will spend one to detect sweep waveform letter Number, when system received signal range be -110dBm~-10dBm when, and current Received Signal power be -11dBm when, in the past Method, which needs to acquire 19 frame scan signals just, can set up the signal path of normal signal, and frame utilization efficiency is (39-19)/39= 0.513, it is established again after signal trace is lost and the scanning signal of so multiframe is spent to go to establish signal path again again, built The signal frame of vertical process does not make any contribution to signal data acquisition and precision, while may also will cause complete machine and resolve signal The decline of precision even results in signal and does not set up before the deadline and cause whole set equipment outputting alarm, this side Method relatively falls behind in actual use.

Summary of the invention

For overcome the deficiencies in the prior art, the present invention provide a kind of microwave approach receiver capture single frames scanning signal from Dynamic gain control method improves microwave landing scanning beam signal when microwave landing airborne equipment uses linear passageway using effect Rate enables microwave landing airborne equipment that more scanning beam signals are used for the resolving of signal angle, improves tradition side The shortcomings that method needs multiframe to establish AGC access.

The technical solution adopted by the present invention to solve the technical problems the following steps are included:

(1) setting initial channel gain control value is L dB, and L is rounded the median of a gain ranging；The ideal output of setting Waveform peak is AMP dBm, and AMP takes the median of AD sampling threshold range, and it is dynamic so that input signal signal-to-noise ratio is all fallen within AD In state；

(2) modulated-analog signal of the AD sampler to inputIt is sampled, wherein T is the time, and U (t) is sweep waveform modulated signal, f_cTo acquire signal carrier,For carrier wave initial phase, the choosing of AD sampling rate Select f_sNot less than 280kHz；After over-sampling, baseband processing, AD sampler outgoing carrier is f_sDiscrete signal, then pass through IQ Demodulation, demodulates baseband signal U (k), and U (k) is the corresponding discrete signal of U (t), k=0, the corresponding time domain waveform of 1,2 ..., k Between be divided into 1/f_s；

(3) baseband signal U (k) and low-pass filtering impulse Response Function h (k) is subjected to convolution, output waveform signals U1 (k)；

(4) it chooses in output waveform signals U1 (k) and is greater than the signal of signal averaging noise gate as basic waveform U2 (k), the maximum value U2 of U2 (k) is calculated_maxAnd minimum value U2_min；Since first point of U2 (k), judge whether U2 (k) occurs More than continuous 21 points in U2_max±0.01*U2_maxOr U2_min±0.01*U2_maxIn range, the signal for meeting this range is all recognized To be invalid signals, corresponding numerical value circle point k1, k2, k3...kN of U2 (k) for defining will be removed after invalid signals as defining Point intercepts useful signal section U2_0-k1(k)、U2_k2-k3(k)、...U2_kN-∞(k)；

(5) when useful signal section only has one section, and the waveform 3dB width acquired be greater than 1 degree less than 5 degree, 12dB width it is big In 2 degree less than 10 degree when, enter step (7), otherwise enter step (6)；

(6) by useful signal section U2_0-k1(k)、U2_k2-k3(k)、...U2_kN-∞(k) Un (k) is uniformly assembled, by Un (k) parameter generation EnterWherein, A is fitting wave-shape amplitude coefficient, and B is waveform widths coefficient, and C is translation coefficient, D is amplitude initial value, enables the root-mean-square value of Un (k) Yu y (k) all the points Wherein N is total points, so that A, B, C, D that following equation is set up are the coefficient for deducing wave function, it is complete thus to deduce signal Whole waveform y (k),

(7) the maximum value S for seeking signal integrity waveform subtracts S with the ideal output waveforms peak A MP of setting, along with setting Fixed initial gain amounts LdB, the as control amount of AGC；

(8) according to the variable trends tracing control gain characteristic of next frame signal, the return step (1) after tracking loss, Otherwise continue to track.

The beneficial effects of the present invention are: establishing channel gain control access using single frames scanning beam, solves tradition Method need may up to 19 frames scanning beam signal, substantially increase channel AGC and establish efficiency, so that more microwave Land scanning signal is used for the resolving of signal angle information；The principle of the invention is simple, and algorithm meets the requirement of real-time of practical application, With stronger engineer application.

Detailed description of the invention

Fig. 1 is the previous automatic gain method flow chart for utilizing multiframe sweep waveform；

Fig. 2 is that microwave approach receiver linear passageway single frames waveform automatically controls gain method flow chart；

Fig. 3 is that actual waveform restores schematic diagram.

Specific embodiment

Present invention will be further explained below with reference to the attached drawings and examples, and the present invention includes but are not limited to following implementations Example.

Referring to Fig. 2, the present invention the following steps are included:

(1) general signal range is -10dBm~-110dBm, dynamic range of signals 100dB, so setting initial channel Gain control value is median 50dB；Echo signal output gain is set as 0dBm；

(2) one frame microwave landing sweep waveform of AD sampler port processing, and demodulate generation baseband waveform.Process is as follows:

The modulated-analog signal of AD sampler input mouth isT is the time, one The t of frame scan signal value within the scope of 2.432ms~15.688ms, U (t) are sweep waveform modulated signal, f_cFor acquisition letter Number carrier wave,For carrier wave initial phase.Bandwidth of U (t) signal on carrier wave is 140kHz, and 140kHz is signal after modulation Minimum bandwidth, using bandpass sampling principle, AD sampling rate is selected as f_s=21MHz, 200 times of frequency modulating signal pass through After sampling, baseband processing, signal outgoing carrier is f_sDiscrete signal, then by IQ demodulate, demodulate baseband signal be U (t) corresponding discrete signal U (k), k=0 are divided into 1/f between the corresponding time domain waveform of 1,2 ..., k_s。

(3) low-pass filtering.Process is as follows:

The baseband signal U (k) and low-pass filtering impulse Response Function h (k) that step (2) are obtained carry out convolution, export and are U1(k).Wherein the corresponding corresponding filter bandwidht of amplitude-frequency characteristic of h (k) is 70kHz；Stopband attenuation is 30dB, stopband attenuation frequency ≤150kHz。

(4) identify that available waveforms, process are as follows:

Signal in the output waveform signals U1 (k) of selecting step (3) greater than signal averaging noise gate is as basic wave Shape U2 (k), U2 (k) are contained in U1 (k), calculate the maximum value U2 of U2 (k)_maxAnd minimum value U2_min.From first point of U2 (k) Start, judges whether U2 (k) continuous 21 points occurs in U2_max±0.01*U2_maxOr U2_min±0.01*U2_maxIt, will in range The signal for meeting this range is regarded as invalid signals, by the U2 (k) thus defined corresponding numerical value circle point k1, k2, k3, K4 ... etc., as defining a little for useful signal, intercept out useful signal section U2_0-k1(k)、U2_k2-k3(k)、U2_k4-∞(k) ....

(5) judge whether have complete waveform, process is as follows:

According to the useful signal section that step (4) obtain, when useful signal section only has one section, and the waveform 3dB width acquired When being greater than 2 degree less than 10 degree less than 5 degree, 12dB width greater than 1 degree, (7) are entered step, (6) are otherwise entered step.

(6) pass through top characteristic or lower along characteristic deduction complete waveform, process is as follows:

The part useful signal section U2 that step (4) are obtained_0-k1(k)、U2_k2-k3(k)、U2_k4-∞(k) ..., by these believe The signal of number section composition uniformly assembles Un (k), and Un (k) parameter is substituted intoA is fitting Wave-shape amplitude coefficient, B are waveform widths coefficient, and C is translation coefficient, and D is amplitude initial value, enable Un (k) and y (k) all the points Root-mean-square valueWherein N is total points, so that following equation is set up A, B, C, D be the coefficient for deducing wave function, thereby establish and deduce waveform y (k): the practical signal for restoring waveform effect Figure is as shown in Figure 3.

(7) complete waveform and ideal output waveforms peak difference add initial control gain S, are rounded control AGC gain amount, Process is as follows:

The maximum value S for the complete waveform that the signal integrity waveform or (5) step for asking (6) step to obtain directly obtain, The ideal output waveforms peak value 0 that step 1 is set subtracts S, adds the initial gain amounts 50dB of step (1) setting, as AGC's Control amount.

(8) gain characteristic is controlled according to the Trend tracing of next frame signal Small variables, is turned again to after tracking is lost Start, restarts, otherwise, continue to track.

Claims (1)

1. a kind of microwave approach receiver captures single frames scanning signal auto gain control method, it is characterised in that including following steps It is rapid:

(1) setting initial channel gain control value is L dB, and L is rounded the median of a gain ranging；Set ideal output waveforms Peak value is AMP dBm, and AMP takes the median of AD sampling threshold range, and all falls within input signal signal-to-noise ratio in AD dynamic；

(2) modulated-analog signal of the AD sampler to inputIt is sampled, wherein t is Time, U (t) are sweep waveform modulated signal, f_cTo acquire signal carrier,For carrier wave initial phase, the selection of AD sampling rate f_sNot less than 280kHz；After over-sampling, baseband processing, AD sampler outgoing carrier is f_sDiscrete signal, then by IQ solve It adjusts, demodulates baseband signal U (k), U (k) is the corresponding discrete signal of U (t), k=0, between the corresponding time domain waveform of 1,2 ..., k It is divided into 1/f_s；

(3) baseband signal U (k) and low-pass filtering impulse Response Function h (k) is subjected to convolution, output waveform signals U1 (k)；

(4) signal for being greater than signal averaging noise gate in output waveform signals U1 (k) is chosen as basic waveform U2 (k), meter Calculate the maximum value U2 of U2 (k)_maxAnd minimum value U2_min；Since first point of U2 (k), judge U2 (k) whether the company of occurring more than Continue 21 points in U2_max±0.01*U2_maxOr U2_min±0.01*U2_maxIn range, the signal for meeting this range is regarded as nothing Signal is imitated, corresponding numerical value circle point k1, k2, the k3...kN of U2 (k) defined after invalid signals will be removed as defining a little, intercepted Useful signal section U2_0-k1(k)、U2_k2-k3(k)、...U2_kN-∞(k)；

(5) when useful signal section only has one section, and the waveform 3dB width acquired is greater than 1 degree less than 5 degree, 12dB width greater than 2 degree When less than 10 degree, (7) are entered step, otherwise enter step (6)；

(6) by useful signal section U2_0-k1(k)、U2_k2-k3(k)、...U2_kN-∞(k) Un (k) is uniformly assembled, Un (k) is corresponding K parameter value substitutes intoCalculate corresponding y (k), wherein A is fitting wave-shape amplitude coefficient, B For waveform widths coefficient, C is translation coefficient, and D is amplitude initial value, enables the root-mean-square value of Un (k) Yu y (k) all the pointsWherein N is total points so that following equation set up A, B, C, D is the coefficient for deducing wave function, thus deduces signal integrity waveform y (k),

(7) the maximum value S for seeking signal integrity waveform subtracts S with the ideal output waveforms peak A MP of setting, along with setting Initial gain amounts LdB, the as control amount of AGC；

(8) according to the variable trends tracing control gain characteristic of next frame signal, the return step (1) after tracking loss, otherwise Continue to track.