阅读说明：本技术 飞行器测控系统基带零值自动监测方法 (Automatic monitoring method for zero value of base band of aircraft measurement and control system ) 是由 张旭 吴述敏 徐茂格 胡建平 于 2020-03-30 设计创作，主要内容包括：本发明公开的一种飞行器测控系统基带零值自动监测方法,旨在提供一种监测精度高,操作简便,监测可靠的基带零值自动监测方法。本发明通过下述技术方案实现：在FPGA的调制输出端顺次连接数模转换器DA、放大器、滤波器和1切3开关组成连接2选1开关的射频自校准通道；通过2选1开关沿顺时针方向顺次串联连接FPGA接收处理接口的滤波器和模数转换器AD组成接收通道；FPGA将1pps信号与基带输出信号送入到高精度时差测量芯片,对通道1和通道3进行时差测量；将本次基带接收零值与事先标定好的标准基带接收零值进行比较,得到本次测控应答机开机基带接收零值的变化量,根据该变化量对飞行器测控系统接收零值进行校正。(The invention discloses an automatic monitoring method for a zero value of a baseband of an aircraft measurement and control system, and aims to provide an automatic monitoring method for a zero value of a baseband, which has the advantages of high monitoring precision, simplicity and convenience in operation and reliability in monitoring. The invention is realized by the following technical scheme: a modulation output end of the FPGA is sequentially connected with a digital-to-analog converter DA, an amplifier, a filter and a 1-to-3 switch to form a radio frequency self-calibration channel connected with a 2-to-1 switch; a 2-to-1 switch is sequentially connected in series with a filter of the FPGA receiving and processing interface and an analog-to-digital converter AD along the clockwise direction to form a receiving channel; the FPGA sends the 1pps signal and the baseband output signal to a high-precision time difference measuring chip, and time difference measurement is carried out on the channel 1 and the channel 3; and comparing the current baseband receiving zero value with a standard baseband receiving zero value calibrated in advance to obtain the variable quantity of the current measurement and control transponder starting baseband receiving zero value, and correcting the aircraft measurement and control system receiving zero value according to the variable quantity.)

1. A method for automatically monitoring the zero value of a baseband of an aircraft measurement and control system has the following technical characteristics: a field programmable gate array FPGA with a built-in pps generator is adopted, and a modulation output end of the FPGA is sequentially connected with a digital-to-analog converter DA, an amplifier, a filter and a 1-to-3 switch to form a radio frequency self-calibration channel connected with a 2-to-1 switch; a 2-to-1 switch is sequentially connected in series with a filter of the FPGA receiving and processing interface and an analog-to-digital converter AD along the clockwise direction to form a receiving channel; the FPGA sends 1pps signals to a channel 1 and a channel 2 of the high-precision time difference measuring chip at the same time, and self-calibration is carried out on the measuring channel of the high-precision time difference measuring chip; the FPGA respectively sends the 1pps signal and the baseband output signal to a high-precision time difference measurement chip measurement channel 1 and a high-precision time difference measurement channel 3 for time difference measurement to obtain a transmitting zero value of the starting-up baseband of the measurement and control system, compares the transmitting zero value with a standard baseband transmitting zero value calibrated in advance to obtain a variable quantity of the transmitting zero value of the starting-up baseband of the measurement and control system, and corrects the transmitting zero value of the aircraft measurement and control system according to the variable quantity; then, the baseband output signal is sent to a receiving channel through a radio frequency calibration channel in a loopback mode, the measurement of the time delay of the whole loop from the transmitting to the receiving is completed in a pseudo code ranging or carrier ranging mode, and a baseband transmitting zero value and a radio frequency calibration channel zero value calibrated in advance are subtracted from the baseband transmitting zero value to obtain the current baseband receiving zero value; and comparing the current baseband receiving zero value with a standard baseband receiving zero value calibrated in advance to obtain the variable quantity of the current measurement and control system starting baseband receiving zero value, and correcting the aircraft measurement and control system receiving zero value according to the variable quantity.

2. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: and a 1pps generator arranged in the FPGA sends the generated 1pps signals to an input port 1 and an input port 2 of the high-precision time difference measurement chip at the same time, so that time difference measurement is completed, and measurement deviation among channels of the high-precision time difference measurement chip is compensated and corrected.

3. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: the signal path difference between the input port 1 and the input port 2 of the FPGA from 1pps output to the high-precision time difference measuring chip is printed circuit board PCB wiring, and the generated time delay difference can be accurately calibrated in advance and is a fixed value.

4. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: a1 pps generator arranged in the FPGA sends a generated 1pps signal into a high-precision time difference measuring chip channel 1, an FPGA modulation output signal is filtered by a digital-to-analog converter DA, an amplifying circuit and a filter and then is sent into a high-precision time difference measuring chip channel 3 after passing through a 1-cut 3 switch, the time difference value between an input port 1 and the input port 3 is measured by the high-precision time difference measuring chip, a transmitting zero value of a starting baseband of the measurement and control system is obtained, and the transmitting zero value is compared with a calibrated standard baseband transmitting zero value, namely the variable quantity of the starting baseband transmitting zero value of the measurement and control transponder.

5. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: the FPGA modulation output signal is filtered by a digital-to-analog converter DA, an amplifying circuit and a filter, then is sent to a radio frequency self-calibration channel through a 1-switch-3 switch, enters a receiving channel through a 2-to-1 switch, and is converted into a baseband digital signal entering the FPGA after being filtered by the filter and an analog-to-digital converter AD.

6. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: and the baseband digital signal processes the received baseband digital signal in the FPGA in a pseudo code ranging or carrier ranging mode to complete the measurement of the time delay from transmission to reception of the whole loop.

7. The aircraft measurement and control system baseband zero value automatic monitoring method according to claim 1, characterized in that: and subtracting a zero value of a radio frequency self-calibration channel calibrated in advance from the measured value of the transmitted-received time delay to obtain a baseband transmitting and receiving zero value sum, subtracting a baseband transmitting and receiving zero value sum from the baseband transmitting and receiving zero value sum to obtain a baseband receiving zero value, and comparing the baseband receiving zero value measured by the starting up of the time with a standard baseband receiving zero value calibrated in advance to obtain the variable quantity of the baseband receiving zero value of the starting up of the time.

Technical Field

The invention relates to a method for automatically monitoring the change of a baseband receiving and transmitting zero value in an aircraft measurement and control system. The aircraft measurement and control system comprises a satellite measurement and control system, an unmanned aircraft measurement and control system, an aviation/aerospace aircraft measurement and control system, an inter-satellite measurement and control system and the like.

Background

The aircraft measurement and control system comprises subsystems such as external measurement, remote measurement, communication, safety and the like, is a unique channel for communicating the aircraft with the ground, is also a unique channel and means for knowing and controlling the position, speed, attitude and operation working state of the aircraft on the ground, and is one of systems which are related to the success and safety of aircraft tests. The aircraft measurement and control system mainly comprises a normal transmitting channel, a zero value calibration channel and a normal receiving channel. Taking one receiving and one transmitting as an example, the normal transmitting channel is composed of a radio frequency transmitting channel (including a DA1, a filter and a frequency converter), a coupler and a transmitting antenna; the normal receiving channel is composed of a receiving antenna, a combiner, a radio frequency receiving channel and AD 2.

The measuring devices used in the field of emission at present are mainly optical measuring systems and radio measuring systems. The optical measurement system is a measurement system which works through visible light, infrared light and laser equipment and measures phenomena and data in an aircraft flight test. The device has the advantages of simple structure, high measurement precision and capability of recording the whole event occurrence process in detail; the method has the disadvantages of short action distance, great influence by climatic conditions, difficulty in giving data in real time and difficulty in processing the data. The radio measurement system measures the position, speed, acceleration and the like of the space vehicle through the characteristics of electromagnetic waves propagated in space. Mainly comprises a pulse measuring system and a continuous wave measuring system. The radio measuring equipment has the advantages of long acting distance, no influence of weather, capability of giving out measuring data in real time and high measuring precision; the disadvantage is that the equipment is complex and the attitude change of the aircraft cannot be observed carefully.

In aircraft measurement and control systems, the distance value is a very important measurement element. The accuracy of the zero calibration of the transceiver is more critical to the accuracy of the time synchronization, which affects the accuracy of the clock error measurement and even the accuracy of the 1pps signal output. The errors generated in the ranging process are mainly ranging system errors and ranging random errors. The random noise of the time delay measurement of the receiving and transmitting channel mainly comprises time difference measurement error, envelope detection time delay jitter error, power divider time delay jitter error and directional coupler time delay jitter error. The system error comprises an atmospheric transmission error, a device zero value error and the like. The time delay of the equipment simulation device changes along with the temperature and needs to be accurately calibrated. In addition, the time delay part of the digital circuit changes along with the on/off of the equipment, and the digital circuit needs to be calibrated in a system with high measurement precision requirement. The distance measurement of the target is typically done by a two-way time delay measurement. The target distance measurement by bidirectional time delay means that a target distance value can be obtained by measuring bidirectional transmission time of a radio signal or an optical signal which is sent to an aircraft target and then returned to receive and calculating in combination with the propagation speed of the radio signal in space. The existing two-way time delay ranging mode in the field of aircraft measurement and control mainly comprises the modes of sidetone ranging, spread spectrum coherent ranging, spread spectrum incoherent ranging, data transmission signal measurement and the like. In any measurement mode, the distance value obtained by the measurement and control system comprises a real space distance value, a distance zero value of measurement equipment at two ends, an error term caused by atmosphere and the like. To obtain a real spatial distance value, the distance zero values of the two measuring devices must be measured and subtracted. The accuracy of the distance zero calibration directly affects the accuracy of the target distance measurement.

The zero calibration method adopted by the measurement and control system is a day and place respective zero calibration method. For zero value calibration of a ground system, two methods, namely a calibration tower zero calibration frequency converter zero calibration method and a double-offset small-frequency-offset direct distance zero calibration method, are generally adopted. The measurement of the distance zero is essentially a measurement of the signal transmission and processing delays of the system. The measurement of signal delay is generally that a sending end sends a periodic pseudo-random sequence to pass through a tested system, a receiving end synchronizes the pseudo-random sequence to give a synchronization indication, and the delay difference between a local pseudo-random sequence of the receiving end and the pseudo-random sequence of the sending end is compared to obtain the signal transmission delay.

In the existing zero value calibration method, a method of measuring an aircraft-mounted device by using a precision instrument is adopted; the ground system adopts a method of zero calibration to the tower or zero calibration to the offset feed, and the method is widely applied to the aircraft measurement and control system. The zero value calibration method for the measurement and control system equipment generally refers to the sum of the transmitting zero value and the receiving zero value, and does not separately mark the transmitting zero value and the receiving zero value. The method adopts a precision instrument testing method to calibrate the zero value of the aircraft carrying end equipment in advance, and the precision instrument cannot be adopted to monitor the change of the zero value of the baseband in the on-orbit process. The zero values in the device comprise zero values of the radio frequency channel part and zero values of the digital baseband part, wherein the zero values of the radio frequency channel part fluctuate with temperature change to ns magnitude; the zero value of the digital baseband section varies by tens of ps during the device power-on and power-off process. The requirement of the existing measurement and control system on the distance measurement precision is usually ns magnitude, on one hand, the stability of the radio frequency channel zero value is ensured in a temperature control mode, on the other hand, the stability of the radio frequency channel zero value is monitored in real time through a monitoring loop, and no monitoring measure is taken for the zero value change of a baseband part. Along with the original higher requirement of the measurement precision, the ranging precision is improved from the original ns magnitude to the ps magnitude. At this time, the zero value change of the digital baseband part caused by the power-on and power-off cannot be ignored. However, the existing zero value calibration method does not monitor the zero value change of the digital baseband, especially for the aircraft-mounted equipment, calibration cannot be performed by a precise instrument after startup and shutdown, and the existing channel online monitoring can only monitor the zero value change of the radio frequency channel part. Therefore, it is necessary to adopt an effective method to monitor the change of the baseband zero value caused by the startup and shutdown online.

Disclosure of Invention

In order to overcome the defects of baseband zero value transceiving monitoring of the existing aircraft measurement and control system, zero value calibration precision of measurement and control system equipment is improved, and the range measurement precision of the aircraft measurement and control system in the ps magnitude order is realized. The invention provides an automatic monitoring method for a baseband zero value of an aircraft measurement and control system, and aims to provide an automatic monitoring method for a baseband zero value of an aircraft measurement and control system, which has the advantages of high monitoring precision, simplicity and convenience in operation, reliability in monitoring, no need of any external system cooperation and no limitation on the type and the measurement and control mode of the aircraft.

The above object of the present invention can be achieved by the following means. A method for automatically monitoring the zero value of a baseband of an aircraft measurement and control system has the following technical characteristics: a field programmable gate array FPGA with a built-in pps generator is adopted, and a modulation output end of the FPGA is sequentially connected with a digital-to-analog converter DA, an amplifier, a filter and a 1-to-3 switch to form a radio frequency self-calibration channel connected with a 2-to-1 switch; a 2-to-1 switch is sequentially connected in series with a filter of the FPGA receiving and processing interface and an analog-to-digital converter AD along the clockwise direction to form a receiving channel; the FPGA sends 1pps signals to a channel 1 and a channel 2 of the high-precision time difference measuring chip at the same time, and self-calibration is carried out on the measuring channel of the high-precision time difference measuring chip; the FPGA sends a 1pps signal and a baseband output signal to a high-precision time difference measurement chip measurement channel 1 and a channel 3 for time difference measurement to obtain a transmitting zero value of a starting-up baseband of the current measurement and control transponder, compares the transmitting zero value with a standard baseband transmitting zero value calibrated in advance to obtain a variable quantity of the transmitting zero value of the starting-up baseband of the current measurement and control transponder, and corrects the transmitting zero value of an aircraft measurement and control system according to the variable quantity; then, the baseband output signal is sent to a receiving channel through a radio frequency calibration channel in a loopback mode, the measurement of the time delay of the whole loop from the transmitting to the receiving is completed in a pseudo code ranging or carrier ranging mode, and a baseband transmitting zero value and a radio frequency calibration channel zero value calibrated in advance are subtracted from the baseband transmitting zero value to obtain the current baseband receiving zero value; and comparing the current baseband receiving zero value with a standard baseband receiving zero value calibrated in advance to obtain the variable quantity of the current measurement and control transponder starting baseband receiving zero value, and correcting the aircraft measurement and control system receiving zero value according to the variable quantity.

Compared with the prior art, the invention has the following beneficial effects:

the monitoring precision is high. Aiming at the problem that the change of a baseband zero value is not monitored in engineering application, the change of the baseband receiving and sending zero value is considered to enter a system zero value calibration, a testing method is improved by adopting main devices such as a field programmable gate array FPGA (field programmable gate array) with a built-in pps generator, a high-precision time difference measuring chip and the like, and the monitoring of the change of the baseband receiving and sending channel zero value is realized through a formed measuring loop and a calibration channel, so that the baseband zero value of an aircraft carrier end can be monitored on line, the zero value calibration precision of a measurement and control system is improved, and the distance measurement precision of the aircraft measurement and control system is effectively improved; a solid foundation is laid for ensuring the smooth operation and the satisfactory success of the test task with the high-precision measurement requirement.

The operation is simple. Aiming at the characteristics of multiple signal channels, high signal transmission rate and high clock signal precision requirement of an aircraft measurement and control system, the invention adopts a 2-to-1 switch to sequentially connect a filter of an FPGA receiving and processing interface and an analog-to-digital converter AD in series along the clockwise direction to form a receiving channel, a self-calibration channel and a high-precision time difference measurement chip, can effectively carry out on-line monitoring on a baseband zero value, does not increase the equipment difficulty, does not need any external system cooperation, has no limitation on the type and the measurement and control mode of the aircraft, has simple method and is suitable for a high-precision measurement system. The defect that zero values of the aircraft carrier-end equipment are calibrated in advance through a precision instrument and the change of the zero values of the baseband cannot be monitored by the precision instrument in the in-orbit process in the prior art is overcome.

The monitoring is reliable. Comparing the base band emission zero value obtained by the measurement with a standard base band emission zero value calibrated in advance to obtain the variable quantity of the base band emission zero value of the starting-up of the current measurement and control transponder, and correcting the aircraft measurement and control system emission zero value according to the variable quantity; then, the baseband output signal is sent to a receiving channel through a radio frequency calibration channel in a loopback mode, and the measurement of the time delay of the whole loop from the transmitting to the receiving is completed in a pseudo code ranging or carrier ranging mode; subtracting a base band transmitting zero value and a radio frequency calibration channel zero value calibrated in advance from the received signal to obtain a current base band receiving zero value; and comparing the base band receiving zero value of this time with a standard base band receiving zero value calibrated in advance to obtain the variable quantity of the base band receiving zero value of this time, and correcting the aircraft measurement and control system receiving zero value according to the variable quantity. The method marks the base band transmitting zero value and the receiving zero value independently, and is suitable for a bidirectional measurement system needing transmitting and receiving zero value sum and a double unidirectional measurement system needing transmitting and receiving zero value difference.

The method is simple to operate, effectively realizes automatic monitoring of the zero value change of the baseband, and is suitable for the measurement and control system of any aircraft type and any measurement and control mode.

Drawings

The method is further described with reference to the accompanying drawings and the detailed description.

FIG. 1 is a schematic diagram of an automatic monitoring circuit for the zero value of a base band of an aircraft measurement and control system.

Detailed Description

See fig. 1. According to the invention, a field programmable gate array FPGA with a built-in pps generator is adopted, and a modulation output end of the FPGA is sequentially connected with a digital-to-analog converter DA, an amplifier, a filter and a 1-to-3 switch to form a radio frequency self-calibration channel connected with a 2-to-1 switch; a 2-to-1 switch is sequentially connected in series with a filter of the FPGA receiving and processing interface and an analog-to-digital converter AD along the clockwise direction to form a receiving channel; the FPGA sends 1pps signals to a channel 1 and a channel 2 of the high-precision time difference measuring chip at the same time, and self-calibration is carried out on the measuring channel of the high-precision time difference measuring chip; the FPGA respectively sends the 1pps signal and the baseband output signal to a high-precision time difference measurement chip measurement channel 1 and a high-precision time difference measurement channel 3 for time difference measurement to obtain a transmitting zero value of the starting-up baseband of the measurement and control system, compares the transmitting zero value with a standard baseband transmitting zero value calibrated in advance to obtain a variable quantity of the transmitting zero value of the starting-up baseband of the measurement and control system, and corrects the transmitting zero value of the aircraft measurement and control system according to the variable quantity; then, the baseband output signal is sent to a receiving channel through a radio frequency calibration channel in a loopback mode, the measurement of the time delay of the whole loop from the transmitting to the receiving is completed in a pseudo code ranging or carrier ranging mode, and a baseband transmitting zero value and a radio frequency calibration channel zero value calibrated in advance are subtracted from the baseband transmitting zero value to obtain the current baseband receiving zero value; and comparing the current baseband receiving zero value with a standard baseband receiving zero value calibrated in advance to obtain the variable quantity of the current measurement and control system starting baseband receiving zero value, and correcting the aircraft measurement and control system receiving zero value according to the variable quantity.

And a 1pps generator in the FPGA simultaneously transmits the generated 1pps signals to an input port 1 and an input port 2 of the high-precision time difference measurement chip, the time difference between the input port 1 and the input port 2 is measured, the measurement deviation between the channels of the high-precision time difference measurement chip is compensated and corrected, and the self-correction of the high-precision time difference measurement chip is completed.

The signal path difference between the input port 1 and the input port 2 of the FPGA from 1pps output to the high-precision time difference measurement chip is printed circuit board PCB wiring, and the generated time delay difference can be accurately calibrated in advance and is a fixed value.

A1 pps generator in the FPGA simultaneously transmits a generated 1pps signal to an input port 1 of a high-precision time difference measuring chip, an FPGA modulation output signal is filtered by a digital-to-analog converter DA, an amplifying circuit and a filter and then is transmitted to an input port 3 of the high-precision time difference measuring chip through a switch of a 1-switch 3, the time difference value between the input port 1 and the input port 3 is measured by the high-precision time difference measuring chip, a transmitting zero value of a starting base band of the measurement and control system is obtained, and the transmitting zero value is compared with a calibrated standard base band transmitting zero value to obtain the variable quantity of the starting base band transmitting zero value of the measurement and.

The FPGA modulation output signal is filtered by a digital-to-analog converter DA, an amplifying circuit and a filter, then is sent to a radio frequency self-calibration channel through the other path of a 1-switch 3-switch, is selected to enter a receiving channel through a 2-to-1 switch, and is converted into a baseband digital signal entering the FPGA after being filtered by the filter and an analog-to-digital converter AD.

And the baseband digital signal processes the received baseband digital signal in the FPGA in a pseudo code ranging or carrier ranging mode to complete the measurement of the time delay from transmission to reception of the whole loop. And subtracting the zero value of the radio frequency self-calibration channel calibrated in advance from the measured value to obtain the sum of the receiving and transmitting zero values of the baseband. The FPGA obtains a baseband receiving zero value by using the baseband receiving zero value and subtracting the baseband transmitting zero value, and then compares the baseband receiving zero value measured by the current measurement and control transponder starting with a standard baseband receiving zero value calibrated in advance, namely the variable quantity of the baseband receiving zero value of the current starting.

The foregoing is directed to the preferred embodiment of the present invention and it is noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.