RU2778141C1 - Multi-position surveillance system - Google Patents

Abstract

FIELD: aircraft flight control.

SUBSTANCE: invention relates to the field of flight control of aircraft and can be applied in multi-position airspace surveillance systems used to control aircraft flights on the route and in the area of airfields. Each of the N identical receiving sensors MPSS additionally contains a frequency separation device (FSD), a television signal receiver (TSR), an additional ADC, a control strobe driver and a switch. The input of the CRU is connected to the output of the receiving antenna and consists of the combined inputs of a high-pass filter (HPF) and a low-pass filter (LPF) connected in parallel. The output of the HPF is connected to the input of the receiver and is the first output of the FSD. The TSR receiver input is connected to the low-pass filter output, which is the second output of the FSD. The signal input of the additional ADC is connected to the output of the TSR receiver. The clock input of the additional ADC and the input of the control strobe shaper are connected to the output of the local clock. The first (signal) input of the switch is connected to the ADC output, the second (signal) input - to the output of the additional ADC, the third (control) input - to the output of the control strobe shaper, and the output is the sensor output.

EFFECT: improving the accuracy and reliability of the multi-position surveillance system (MPSS).

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Description

The invention relates to the field of flight control of aircraft (LA) and can be applied in multi-position airspace surveillance systems used to control aircraft flights on the route and in the area of airfields.

A multi-position surveillance system (MSS) refers to radio-technical means of airspace surveillance with spaced receiving sensors and a common server for receiving and combining the signals received by the sensors emitted by the aircraft, with subsequent assessment of the position parameters (coordinates) of the detected aircraft.

In MSSN, the measurement of the parameters of the spatial position of the detected aircraft is carried out by linking the signals received by the receiving sensors to the readings of a single time common to all sensors (time synchronization of the sensors), and then estimating the difference in the arrival times of the signals in the receiving channels of the sensors, taking into account the known spatial position of the sensors.

MSSNs are known, which differ in the options for time synchronization of receiving sensors using various sources of common time.

MSSN is known, in which the synchronization of receiving sensors is performed from a single time source (common clock) that generates periodic pulses (marks) of time [1, Figure 10]. In the specified MPSN, analog-to-digital converters (ADC) 6, the inputs of which are connected to the outputs of the corresponding receivers 5 with receiving antennas 4, of all receiving sensors 1, are supplied with the same marks of a single current time, generated by a highly stable common clock generator 3 and tying (synchronizing) identical fragments signals received by N receiving sensors 1 to a single time scale (Fig. 1).

The common clock 3 that generates a single current time, depending on the relative position of the server 2 and spaced sensors 1, can be located both as part of the MSSN on the server 2 or in one of the receiving sensors 1, and outside the MSSN (Fig. 1).

Synchronization from a common clock 3 requires the transmission of a universal time signal over analog or digital physical lines of terrestrial wire communication or over air radio communication channels (data transmission channels), which must be without distortion, with known calibrated time delays (in a particular case, the same) in real time transmit branched common time signals to all receiving sensors 1. The practical implementation of highly stable physical transmission lines for analog (digital) signals with the same or fixed calibrated time delays is a complex technical task and requires additional material and construction costs.

Known MSSN, in which the synchronization of the receiving sensors 1 does not require the use of a common clock, the presence of highly stable physical signal transmission lines with the same or fixed calibrated time delays and is performed from external reference time signals received in the MSSN via a radio channel from satellites of the global navigation satellite system (GLONASS) or global positioning system (GPS, etc.) [1, Figure 13]. In such MSSNs, each sensor 1 has identical local clocks 3 and additional GLONASS/GPS receivers 7 for receiving satellite signals synchronizing local clocks 3 for synchronous operation of analog-to-digital converters 6 of spaced sensors 1 (Fig. 2). The global satellite system is used to provide a common common time reference signal for each of the receiving sensors 1. Satellite signals are highly accurate and stable system time, which is an important factor to ensure accurate measurement of the position parameters of objects of observation. This time can be used as a common common time for all sensors 1.

Synchronization of MSSN using GLONASS and GPS is simpler compared to the option of using an external common clock (Fig. 1), since no additional external equipment is required, no communication channels are needed, and the condition for ensuring the same or fixed calibrated signal transmission time delays is not required. in sensors.

The disadvantage of MSSN using GLONASS and GPS is the deterioration and disruption of performance during fading of satellite signals due to changes in the parameters of the ionosphere and the earth's magnetic field, as well as the appearance of interfering signals from third-party electronic means. Another drawback is the need to use additional equipment in the sensors 1 in the form of GLONASS/GPS receivers 7 operating at carrier frequencies of GLONASS and GPS satellite systems transmitters. Additionally, the disadvantages include the possibility of jamming and replacing GLONASS and GPS signals.

The closest analogue (prototype) of the claimed invention is MPSN [1, Figure 12]. The MSSN prototype contains N (at least 3) identical receiving sensors 1, each of which contains a receiver 5 with a receiving antenna 4, an ADC 6 and a local clock 3, a common server 2, N inputs of which are connected to the outputs of N sensors 1, and also the transmitter of the control radio signal 8 (Fig. 3). The ADC 6 of the receiving sensors 1 are clocked by clock pulses of identical local clocks 3. In the MSSN prototype, synchronization of the receiving sensors 1 is provided without the use of an external common clock with data transmission channels and is performed using an external control radio signal generated by the control radio signal transmitter 8 and sent to the MSSN via a radio channel. The control radio signal transmitter 8, containing the control radio signal generator 9 and the transmitter 10 with the transmitting antenna 11, is installed in the MSSN location area at a certain point on the earth's surface with known coordinates, subject to the obligatory condition of ensuring direct radio visibility of all receiving sensors 1. In the server 2, which combines the output signals sensors 1, the estimation of the temporal position of the signals received from the object of observation by the sensors 1 is performed, relative to the clock pulses of the local clock 3 and the control radio signal.

In the MPSN prototype, the control radio signal is emitted by the transmitter of the control radio signal 8 at a carrier frequency that matches the carrier frequency of the radio signals emitted by the detected aircraft, and is received by the same receiving sensor antennas 1, which receive radio signals from the aircraft. Receipt in the receiving channels of the sensors 1 timestamps, markers or other identical fragments of the control radio signal provides binding (synchronization) of the local clock 3 of all receiving sensors 1 to a single time scale.

The disadvantage of the MPSN prototype is the need to install and use additional equipment - an external transmitter of the control radio signal 8 within the line of sight of the receiving sensors 1.

Another disadvantage of the MPSN-prototype is the reduction in the characteristics of measuring the coordinates of the aircraft due to the deterioration of the performance of the MPSN in case of unstable operation or failure of the transmitter of the control radio signal 8, with permanent or temporary shading of the transmitter of the control radio signal 8 by natural and deliberate static or moving obstacles in the direction of the sensors, as well as when exposed to radio interference. The decrease in the characteristics of measuring the coordinates of the aircraft, which occurs under the conditions of a changing quality of the transmitter of the control radio signal 8, as well as a changing shading and interference environment, is due to the fact that the possibility of additional synchronization of the MSSN sensors from alternative sources of common time is not taken into account, which does not allow improving the accuracy and reliability of the system . The absence of additional synchronization of the MSSN sensors also does not allow improving the MSSN - increasing its reliability and accuracy by connecting other sources for obtaining synchronizing information, for example, such as radio signals from local television centers.

In the development of the present invention, a technical problem was solved, which consists in creating an MPSN, devoid of the above disadvantages.

The technical result of the invention is to improve the accuracy and reliability of MPSN.

The specified technical result is achieved by the fact that the air traffic control MSSN containing N (at least 3) identical receiving sensors 1, each of which contains a receiver 5, a receiving antenna 4, an ADC 6 and a local clock 3, a server 2, N inputs of which are connected to outputs of the corresponding N sensors 1, as well as the transmitter of the control radio signal 8, containing the shaper of the control radio signal 9 and the transmitter 10 with the transmitting antenna 11, is additionally equipped with a frequency separation device (FDD) 12, connected to the input to the output of the receiving antenna 4 and consisting of parallel-connected high-pass filter (HPF) 17 and low-pass filter (LPF) 18, the combined inputs of which are the input of the CRU 12, the output of the HPF is connected to the input of the receiver 5 and is the first output of the CRU 12, the television signal receiver (TVS) 14, the input of which is connected to the output of the LPF 18, which is the second output of the CRU 12, an additional ADC 15, the signal input of which is connected to the output of the receiver TVS 14, and the clock input - to the output of the local clock 3, the shaper of the control strobe 13, the input of which is connected to the output of the local clock 3, and the switch 16, the first (signal) input of which is connected to the output of the ADC 6, the second (signal) input - to the output of the additional ADC 15, the third (control) input to the output of the shaper of the control strobe 13, and the output is the output of the sensor 1.

In FIG. 1 shows the well-known functional diagram of the MSSN [1], in which the synchronization of receiving sensors 1 is performed from a single time source (common clock) that generates periodic pulses (marks) of time.

In FIG. 2 shows a well-known functional diagram of the MPSN, in which the synchronization of the receiving sensors 1 does not require the use of a common clock and is performed from external reference time signals received in the MPSN via a radio channel from the satellites of the global navigation satellite system (GLONASS) or the global positioning system (GPS, etc.). .) [1, Figure 13].

In FIG. 3 shows a functional diagram of the prototype MPSN [1, Figure 12].

In FIG. 4 shows a functional diagram of the proposed MPSN.

The following designations are used in the diagrams:

1 - sensor,

2 - server,

3 - clock,

4 - receiving antenna,

5 - receiver,

6 - analog-to-digital converter,

7 - GLONASS/GPS receiver,

8 - transmitter of the control radio signal,

9 - shaper of the control radio signal,

10 - transmitting device,

11 - transmitting antenna,

12 - frequency separation device,

13 - control strobe driver,

14 - television signal receiver,

15 - additional analog-to-digital converter,

16 - switch,

17 - high pass filter,

18 - low pass filter.

The implementation of the proposed MPSN is as follows.

The signals from the transmitting antenna of the detected aircraft and the signals from the transmitting antenna 11 of the transmitter of the control radio signal 8 are received by the receiving antennas 4 of each of the N (at least 3) identical receiving sensors 1, pass the corresponding high-pass filters 17, which pass the radio signals of the aircraft, as well as the transmitter of the control radio signal 8 and blocking the passage of television signals, are amplified in the respective receivers 5, configured for the coordinated reception of pulse sequences of aircraft signals, as well as the transmitter of the control radio signal 8, and are converted into a digital code at discrete times using clock pulses generated by the local clock 3, in the corresponding analog -digital converters 6. The resulting digital sequences from the outputs of the ADC 6 are fed to input 1 of the corresponding switches 16.

At the same time, television signals from the local television center are received by receiving antennas 4 of each of the N sensors 1, pass through the corresponding low-pass filters 18, which transmit television signals and block the passage of high frequencies of the signals of the aircraft and the transmitter of the control radio signal 8, are amplified in the corresponding TVS receivers 14, tuned to a consistent TVS reception, and are converted into a digital code at discrete times using clock pulses generated by the local clock 3 in the corresponding additional ADC 15. The resulting digital sequences from the outputs of the additional ADC 15 are fed to the input 2 of the corresponding switches 16.

The switching of the digital codes of the signals of the aircraft, the transmitter of the control radio signal 8 and television signals to ensure their sequential transmission from the output of each of the N sensors 1 to the corresponding input of the server 2 is performed in the switch 16 by using the output signal of the shaper of the control strobe 13 supplied to the control input of the switch 16 and representing, for example, a 2-bit binary code, the value of which varies depending on the type of transmitted signal. In this case, for example, with a code value of 00, the LA signals can be passed to the output of the switch 16, which is the output of the sensor 1, with code 01 - the control radio signals of the transmitter of the control radio signal 8, and with code 11 - TVS.

Thus, from the output of each of the N sensors 1 through the appropriate communication channels, the server 1 receives in succession the aircraft signals received by the sensors 1, the control radio signals of the transmitter of the control radio signal 8 and television signals.

In the MPSN server 2 in a known manner (like analog and prototype), the aircraft signals received from N sensors 1 are used to determine the spatial coordinates of the aircraft, and the signals of the control radio signal transmitter 8 are used to ensure mutual time synchronization of the sensors 1. Reception by the sensors 1 and transmission to the server 2 of television signals allows you to provide additional relative time synchronization of the sensors 1, which increases the reliability of detection, accuracy characteristics and reliability of measuring the coordinates of the aircraft in the MPSN.

The signal sent by the aircraft is received by N sensors 1 located at a certain distance from each other, at different times, depending on the distance between the aircraft and sensors 1. The difference in the time of reception of the aircraft signal by two arbitrary sensors 1 is described by a spatial hyperboloid on which the aircraft is located. The intersection of hyperboloids corresponding to individual pairs of sensors 1 determines the specific location of the aircraft in space. Thus, the exact location of the object in space is determined. Since the main parameter for calculating the coordinates of the aircraft location point in space is the time of signal arrival, the synchronization of all receiving sensors 1 in time and the accuracy of determining the time come to the fore.

In order to quantify the reduction of the error (error) of synchronization when using TVS, in addition to synchronization from the control radio signal, we determine the value of the dependence of the mean square error (RMS) of synchronization of aircraft radio signals received by sensors in the case of simultaneous timing (synchronization) using control radio signals and TVS .

The time of the current binding (synchronization) of the aircraft radio signal to the control radio signal in the sensor is determined by the expression

where T is the true (real) current time of reception of the radio signal by the aircraft sensor, determined by the distance between the sensor and the aircraft,

Δt ₁ - error (error) binding (synchronization) of the aircraft radio signal to the control radio signal in the sensor.

The time of the current binding (synchronization) of the aircraft radio signal to the TVS in the sensor is determined by a similar expression

where Δt ₂ is the error of binding (synchronization) of the aircraft radio signal to the TVS in the sensor.

It follows from expressions (1) and (2) that the time of simultaneous current binding (synchronization) of the aircraft radio signal to the control radio signal and fuel assemblies in the sensor, taking into account the statistical independence of synchronization over the channels of the pilot radio signal and fuel assemblies, can be determined by the expression

From expression (3), assuming that the values of Δt ₁ and Δt ₂ are distributed uniformly with a zero average value, taking into account the statistical independence of synchronization errors in the channels of the control radio signal and TVS, we obtain the average value of T ₁₂ in the sensor

The average square of the time of simultaneous binding (synchronization) of the aircraft radio signal to the control radio signal and TVS is determined from (3) by the expression

- дисперсия временной синхронизации радиосигнала ЛА к контрольному радиосигналу, равная средней величине квадрата Δt₁,where

- the dispersion of the time synchronization of the radio signal of the aircraft to the control radio signal, equal to the average value of the square Δt ₁ ,

- дисперсия временной синхронизации радиосигнала ЛА к ТВС, равная средней величине квадрата Δt₂.

- dispersion of time synchronization of the radio signal LA to TVS, equal to the average value of the square Δt ₂ .

Using expressions (4) and (5), we obtain an expression for the dispersion of the simultaneous synchronization of the aircraft radio signal by the control radio signal and fuel assemblies.

From expression (6), the RMS of the synchronization of aircraft radio signals received by sensors is determined with simultaneous timing (synchronization) using control radio signals and fuel assemblies

что для ТВС современных телевизионных центров выполняется на практике, и одновременной временной привязке (синхронизации) радиосигналов ЛА, принимаемых сенсорами, при помощи контрольного радиосигнала и ТВС СКО временной синхронизации радиосигналов ЛА уменьшается по сравнению с вариантом синхронизации только по контрольному радиосигналу.As follows from expression (7), under the condition

that for TVS of modern television centers is carried out in practice, and simultaneous timing (synchronization) of aircraft radio signals received by sensors using a control radio signal and TVS RMS of the time synchronization of aircraft radio signals is reduced compared to the synchronization option only by control radio signal.

результирующая СКО синхронизации уменьшится в 2 раза (по сравнению с вариантом синхронизации только по контрольному радиосигналу)In a particular idealized case, when the quantity

the resulting RMSD of synchronization will decrease by a factor of 2 (compared to the synchronization option using only the control radio signal)

СКО уменьшится в ~1,41 разаFor the most likely practical situation where

RMS will decrease by ~1.41 times

Thus, the use of TVS in addition to synchronization from the control radio signal significantly reduces the error (error) of synchronization of the aircraft radio signals received by the sensors, and therefore proportionally reduces the measurement error of the aircraft coordinates in the MSSN.

Introduction to the claimed MPSN for the reception and use of television signals by introducing into each of the N sensors 1 a frequency-separating device 12, consisting of a parallel-connected high-pass filter 17 and low-pass filter 18, a TVS receiver 14, an additional ADC 15, a control strobe driver 13 and a switch 16 for additional relative time synchronization of the sensors 1, which improves the reliability and accuracy of the MSSN, was not used in any of the known MSSNs to determine the location of the aircraft.

Such a set of distinguishing features is absent both in analogues and in the prototype, which proves the compliance of the proposed MPSN with the criterion of "novelty".

Thus, the analysis of the prior art did not reveal objects that have the same set of features as the claimed invention, and, therefore, it is new.

The inventive step of the proposed MSSN is confirmed by the fact that as a result of the search no MSSNs were found that have features that coincide with the distinguishing features of the present invention. All traceable directions for improving the MSTS, reflected in the well-known scientific and technical literature, are associated with the use of time synchronization using a common clock or GPS and GLONASS common time signals or signals coming from an external transmitter of control radio signals. This means that the claimed invention does not follow explicitly from the prior art, and therefore has an inventive step.

An example of a specific implementation of the constituent parts of the MPSN. As a sensor 1 containing a receiving antenna 4, a receiver 5, an ADC 6 and a local clock 3, the receiving station of the serial integrated MSSN "Almanakh" [2], produced by the Research and Production Enterprise (NPP) "CRTS", can be used as a server 2 can be used the processing server MSSN "Almanakh" [2], produced by NPP "CRTS", as a transmitter of the control radio signal 8 can be used as a transmitting station MSSN "Almanakh" [2] or a compact transmitter "GNOM" [3], manufactured by OOO "NPP "CRTS", as well as the aircraft transponder SO-2010 [4], produced by the Institute of Aviation Instrumentation (JSC "Navigator").

Other components of the proposed MPSN can be the corresponding functional blocks and functional elements of the Almanakh MPSN, produced by NPP CRTS, as well as the corresponding standard functional blocks or standard functional elements commercially available, mass-produced and supplied by various manufacturers and companies.

So the high-pass filter 17 and the low-pass filter 18, which form the CRU 12, can be implemented using the SALF-680+ and TNR-1050+ microcircuits, respectively, from Mini-Circuits [5], the control strobe driver 13 and the switch 16 can be implemented on programmable logic integrated circuit (FPGA) of the “Cyclone IV” type manufactured by Altera [6], receiver 5 and TVS receiver 14 can be implemented using a broadband software-controlled receiver module of the AD9361 type [7] or AD9371 type [8] of the manufacturer’s company "Analog Devices", connected to a digital signal processing module, respectively, of the ZedBoard Zynq-7000 ARM / FPGA SoC Development Board type [9] manufactured by Digilent. A National Instruments Company" or Xilinx Zynq-7000 SoC ZC706 Evaluation Kit from Xilinx [10], local clock 3 - using an on-chip clock generator LTC6952 (AD9544) or direct digital signal synthesis on an AD9912 type chip from the manufacturer " Analog Devices” [11].

Thus, the claimed invention is industrially applicable. In addition to air traffic control, the invention can be used in other industries where it is required to determine the location of radio emission sources in space: sea, land and air radio navigation, topography, geological exploration, etc. It has advantages over known technical solutions, consisting in increasing the reliability of detection and the accuracy of measuring the parameters of the position of radio emission sources, which determines its technical and economic efficiency.

Literature

1. National Aerospace Laboratory NLR (2005), NLR-CR-2004-472, Wide Area Multilateration, Report on EATMP TRS 131/04, Version 1.1 [Electronic resource]. URL: https://ext.eurocontrol.int/lexicon/index.php/Wide_area_multilateration#Definition_Source/_ (accessed 25.10.2019); URL: https://docplayer.net/50791604-Wide-area-multilateration-report-on-eatmp-trs-131-04-version-1-1.html (Accessed: 10/25/2019)

2. "Almanac" - an integrated multi-position surveillance system in the airfield and route areas [Electronic resource]. URL: http://www,npp-crts.ru/production/multilateratsiya/almanakh/ (date of access: 10/25/2019)

3. "GNOM" - small-sized AZNV transmitter [Electronic resource]. URL:http://www.npp-crts.ru/production/aznv/gnom/ (date of access: 10/25/2019)

4. Aircraft transponder SO-2010 [Electronic resource]. URL: https://navigat.ru/products/samoletnye-otvetchiki/so-2010/ (date of access: 10/25/2019)

5. Mini-circuits [Electronic resource]. URL: https://www.minicircuits.com/ (date of access: 25.10.2019)

6. Intel FPGA Cyclone [Electronic resource]. URL:https://www.intel.ru/content/www/ru/ru/products/programmable/cyclone-series.html (date of access: 10/25/2019)

7. Description of AD9361 [Electronic resource]. URL: https://www.analog.com/en/products/ad9361.html#product-overview (accessed 10/25/2019)

8. Description of AD9371 [Electronic resource]. URL: https://www.analog.com/en/products/ad9371.html (accessed 10/25/2019)

9. ZedBoard Zynq-7000 ARM/FPGA SoC Development Board [Electronic resource]. URL: https://store.digilentinc.com/zedboard-zynq-7000-arm-fpga-soc-development-board/ (Accessed: 10/25/2019)

10. Xilinx Zynq-7000 SoC ZC706 Evaluation Kit [Electronic resource]. URL: https://www.xilinx.com/products/boards-and-kits/ek-z7-zc706-g.html (Accessed: 10/25/2019)

11. Analog Devices products "Clock signal and synchronization" [Electronic resource]. URL: https://www.analog.com/en/products/clock-and-timing.html (Accessed 10/25/2019).

Claims (2)

1. A multi-position surveillance system containing N identical receiving sensors, each of which contains a receiver, a receiving antenna, an analog-to-digital converter (ADC) and a local clock, a server, N inputs of which are connected to the outputs of the corresponding N sensors, as well as a control radio signal transmitter, containing a serially connected control radio signal generator and a transmitting device with a transmitting antenna, characterized in that each of the N identical receiving sensors additionally includes a frequency separation device (FCD) connected by the input to the output of the receiving antenna and consisting of a high-pass filter (HPF) connected in parallel ) and a low-pass filter (LPF), the combined inputs of which are the input of the CRU, the output of the HPF is connected to the input of the receiver and is the first output of the CRU, the receiver of the television signal (TVS), the input of which is connected to the output of the LPF, which is the second output of the CRU, an additional ADC, whose signal input is connected to the output TVS receiver, and the clocking input - to the output of the local clock, the shaper of the control strobe, the input of which is connected to the output of the local clock, and the switch, the first signal input of which is connected to the output of the ADC, the second signal input - to the output of the additional ADC, the third control input - to the output of the control strobe shaper, and the output is the output of the sensor. 2. Multi-position surveillance system according to claim 1, characterized in that the number N of identical receiving sensors is at least three.

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