RU2164694C2 - Radio navigation procedure and regional system of its implementation - Google Patents

Abstract

FIELD: regional radio navigation. SUBSTANCE: each transceiving station of system emits and receives linear frequency modulation signals from the rest of stations. Time delays of each frequency component of linear frequency modulation signal relative to linear frequency modulation standard are measured and used to form signal of synchronization correction. Signals from n stations are received by instrument of user which identifies stations and computes own coordinates by their known coordinates. Instrument of user includes storage circuit of signals and device comparing linear frequency modulation signals with standard linear frequency modulation signal that make it feasible to raise signal-to-noise ratio and authenticity of determination of time delays of signals. EFFECT: simplified design of regional radio navigation system, decreased cost of its maintenance and improved noise immunity. 2 cl, 3 dwg

Description

 The invention relates to technical means for the rapid determination of the location of vehicles and other moving objects by comparing in one coordinate system the distances found to several radiated beacon devices spaced in space with known coordinates and can be used to provide regional radio navigation.

 A known method for determining location / Korneev B.Yu. (transl.) Global Positioning System (GPS), Moscow, Print JSC, 1994, 76 pp., which consists in the fact that using emitters of 24 high-orbit satellites they create a global radio navigation field, from each satellite they emit on the same operating frequency synchronized radio emission, which is encoded by individual codes inherent in each satellite. At any point in the world, at least seven satellites are in the user's field of vision. The most intense radiations from four satellites are received at the receiving site, satellites are identified by the radiation codes, and their own location is determined by the known current coordinates of the satellites. The GPS global radio navigation system includes a network of 24 high-orbit satellites uniformly distributed in near-Earth space. The on-board equipment of each satellite contains a highly stable VHF generator, encoder, modulator, power amplifier, omnidirectional emitter, control unit, telemetry and communication. The user equipment includes an omnidirectional receiving antenna, a radio receiver, a decoder, a satellite identification unit, a timer-synchronizer, and a coordinate calculator.

 The disadvantage when using the GPS method and system is the dependence of consumers on the US Department of Defense, which owns the GPS system and which may terminate the service of civilian and foreign consumers at its discretion or introduce such changes in the transmission of codes when accurate location becomes impossible. A country that relies entirely on GPS for its navigation needs and purchases the necessary number of user devices falls under the likelihood of dependence, political blackmail and US dictatorship.

 A known method of radio navigation / Japanese Patent N 60-63074, class. G 01 S 5/10, 1991 /, which consists in the fact that a single radionavigation field is created by a superposition of synchronized emissions from a regional network of stations, one of which is the leading one. At the master station, reference clock signals are received, which are constantly emitted by a source outside the scope of the network, using the reference clock signals, internal clock signals are generated, which are sequentially delayed for a time including the signal emission time by the slave stations of the network. At the receiving location, the coordinates of which must be determined, the total radiation of the entire network of stations is received, each station is identified by the time sequence relative to the reference clock signal, the distances to four of them with the highest signal levels are determined by the measured time and phase delays of the arrival of signals from each station the known coordinates of each station calculate their own coordinates.

 A radio navigation system implementing the known method / Japanese Patent N 60-63074, class. G 01 S 5/10, 1991), includes a distributed network of radio-emitted ground stations, one of which is the leading one. The equipment of the leading station includes a receiver of the reference clock signals - accurate time signals constantly emitted by a source outside the scope of the network, an internal clock signal generator, a highly stable master oscillator, a modulator, a power amplifier, an omnidirectional radiating antenna. The hardware complex of the remaining slave stations includes a control clock signal receiver from the master station, a clock delay unit, a highly stable master oscillator, a modulator, a power amplifier, and an omnidirectional radiating antenna. A user device includes a radio receiver, a phase meter, a register of coordinates of radio emitting stations, a coordinate calculator, and an information display device.

 The disadvantages of the known methods of radio navigation and radionavigation system are low noise immunity, the use of large radiation powers to create a regional radio navigation field and the associated high level of interference in the air. In addition, the OMEGA radio navigation system, operating in the SDV range and implementing the known method, ceased to function from 01.10.97 / Nikitin A.A., Khudyakov G.I. The Current State of the Differential Omega Radio Navigation System, Foreign Radio Electronics, M., Radio and Communication, 83, 1982, p. 54-68 /.

 A known method of radio navigation, implemented in the regional radio navigation system "Laurent-S" / European patent N 0315377, class. G 01 S 1/24, 1989 /, which consists in the fact that a regional radio navigation field covering the entire space of a region is created using a network of n radio-emitting stations. The radiation of each of the n stations is encoded with individual codes, which allows each station to be identified at the receiving site. The carrier frequencies, time instants and frequency of the packages of coded emissions are synchronized by identical highly stable frequency standards at each emitting station. Omnidirectional coded emissions from all stations are received at the receiving site, stations are identified by codes, temporary changes in the parameter (phase) of each radiation are measured, time shifts of the coincidence parameters (phase differences) are determined by the propagation time of signals from four stations with the highest signal levels, distances are calculated from these stations to the place of reception and the coordinates of the place of reception are calculated from the known coordinates of the stations.

Known regional radio navigation system "Laurent-S" / European patent N 0315377, class. G 01 S 1/24, 1989 /, consisting of a network of n ground-based radio-emitting stations distributed across a region, each of them includes a series-connected frequency standard (stability ^10-12 ), an encoder, a pulse phase modulator, a power amplifier, an omnidirectional radiating antenna . The station also includes a clock pulse generator synchronizing the operation of the station blocks. The system includes many user devices installed on vehicles and other mobile objects, consisting of a series-connected receiving antenna, a radio receiving device, a decoder, a phase meter, a signal arrival time delay meter, a coordinate calculator, and a location indicator. In addition, the device includes a permanent storage device - a register of coordinates of radio emitting stations, 3n outputs of which are connected to the second inputs of the coordinate calculator, as well as a timer-synchronizer connected to the sync inputs of all other blocks of the device.

 The disadvantages of the known radio navigation system are low noise immunity, the need to use large radiation powers to create a regional radio navigation field and the associated high level of interference in the air. By 2000, the long-wave system Laurent-S will also cease to work / Frank R.L. Modern developments on the LORAN-C system. TIIER, 1983, v. 71, N 10, p. 8-22 /.

A known method of radio navigation, closest to the proposed technical essence / Prepatent RK N 5615, class. G 01 S 5/02, 1997 /, which consists in the fact that the regional radio navigation field is created by synchronized radio emission from a network of n radio-emitting stations, the radiation from each station is encoded with an individual code, which allows each station to be identified, carrier frequencies, time points and frequency of parcels - cycles of encoded signals are synchronized by a highly stable frequency standard. Omnidirectional coded emissions from all stations are received at the receiving site, the codes are identified by the computers stored in the computers of the receiving and measuring devices, the received n coded signals are accumulated during m signal transmission cycles from each station, increasing the signal-to-noise ratio by a factor of ² , preventing malfunctions, measure the functions of cross-correlation between the envelopes of the accumulated signals and the stored code standards, measure the moments of time of maximum correlation and time delays ihoda each n-th signal determined propagation times of signals from four stations with the highest signal levels is calculated distances to these stations and from the known coordinates of stations receiving location coordinates calculated.

A regional radio navigation system is known that is closest to the one proposed in technical essence / Prepatent of the Republic of Kazakhstan N 5817, cl. G 01 S 5/02, 1997 /, consisting of n terrestrial radio transmitting stations whose radiation is synchronized with a frequency standard of stability ^10-12 , each station contains a carrier frequency block, an encoder, a modulator, a power amplifier, an omnidirectional radiating antenna and a block of clock synchronization pulses, the output of which is connected to all sync inputs of the station blocks. The system also includes user devices that are installed at a receiving location that requires coordinates, including a series-connected receiving antenna, a radio receiving device (RPU), a decoder, a time meter for signal arrival delays, a coordinate calculator, and a location indicator. The user devices also include a register of coordinates of radio emitting stations, 3n outputs of which are connected to the second inputs of the computer, and a timer-synchronizer connected to the sync inputs of all other blocks. At the same time, in n-1 radio-emitting slave stations, instead of the frequency standard, carrier frequency blocks are used, each of which contains a radio receiver of the master station signals and a carrier frequency shaper, the clock synchronization block is a clock shaper from the master station signals, and the user device decoder includes analog-to-digital converter (ADC), signal storage device, comparison device - correlator, register of time constants - propagation times of a radio signal fishing between each pair of stations. The RPU output is connected to the ADC input, the output of which is connected to the drive input, n drive outputs are connected to the n first inputs of the correlator, the second n inputs of which are connected to the register of standards of station codes, n outputs of the correlator are connected to the first inputs of the time delay meter, the second inputs of which are connected with n outputs of the register of time constants.

A disadvantage of the known method and system of radio navigation is that in order to satisfy the basic requirement of their functioning - synchronism and temporary stability of operation of all generators of such synchronizing pulses, it is necessary to establish a highly stable (10 ^-12 ) frequency standard, a very expensive device, at the leading radiating station and periodic correction with using the transported standard, as well as the insecurity of the synchronization system from extraneous narrow-band interference.

 The objective of the invention is to develop a method and a long-wave radio navigation system, eliminating synchronization failures, the need for highly stable frequency standards and periodic correction of clock pulses.

 The technical result obtained as a result of the invention is to simplify the maintenance of the system, reduce the cost of the complex of technical means of the radio navigation system and reduce operating costs, as well as increase the noise immunity of the system.

 The required technical result is achieved by the fact that, as in the known method of radio navigation, in the proposed method, a regional radio navigation field is created by synchronized pulsed radio emission from a network of n radio emitting stations, the radiation of each station is encoded to identify it at the receiving place, the sequence of time and frequency of the pulses are synchronized radio emissions, at the receiving location the coordinates of which must be determined, receive coded emissions from all stations, by identifying codes the comfort of the station, the received signals accumulate during m cycles of sending signals from each station, increasing the signal-to-noise ratio m times, preventing malfunctions, measure the time delays of arrival of each n-th pulse signal, determine the propagation times of signals from four stations with the largest levels of signals, calculate the distances to these stations and the coordinates of the receiving location are calculated from the known coordinates of the stations.

 However, in contrast to the known method, in the proposed radio navigation method, a regional radio navigation field is created by synchronized radiation of linear frequency-modulated (LFM) signals, these LFM signals are received at each station, time delays of each frequency received from other stations of the LFM signals are measured relative to The LFM standard stored at each station and used to modulate its own radiation, taking into account the measured time delays and known propagation times of the signal from the rest n-1 stations adjust the timing of each station.

 The required technical result is achieved by the fact that, just as the well-known regional radio navigation system, the proposed system includes n ground synchronized radio-emitting stations, each station contains a master oscillator, encoder, clock synchronization pulse unit, modulator, power amplifier, radiating antenna, receiving antenna and RPU signals of radiating stations, as well as many user devices, including a receiving antenna, a radio receiver, a demodulator, a decoder, a time delay meter rihodov signals radioemitting coordinate register stations, timer-synchronizer, and a coordinate calculator location indicator, wherein the decoder comprises a signal storage device, comparison device, a register code standards, the register time constants (RVC) - propagation times of radio signals between each pair of stations.

 However, unlike the known system, in the proposed regional radio navigation system in each station, the modulator is designed as an LFM modulator, and the register of the LFM standard, a register of time constants, a device for comparing the LFM signal and LFM standard, and a time meter delays and the driver of the synchronization correction signal, and in the user device, the demodulator is designed as a chirp demodulator.

 The required technical result is achieved by the fact that the proposed correction method for synchronizing the operation of each station, with their sequential radiation, using time delays of arrival of the LFM signals from all other stations to generate the correction signal, provides a rigid time reference of the stations relative to each other - the main necessary condition for accurate location determination.

 The invention is illustrated in FIG. 1-3, where in FIG. 1 shows the layout of the emitting stations, in FIG. 2 is a functional diagram of a radiating station; FIG. 3 is a functional diagram of a user device.

 Each radio-emitting station from n stations of the radio navigation system network includes a master oscillator (MZ) 1, an encoder (K) 2 that generates the sequence, moment and interval of the signal emission from each station, linear frequency modulator (LFM) 3, power amplifier (AM) 4, clock synchronization unit (BTSM) 5, a radiating antenna, a radio receiving antenna, a radio receiving device (RPU) 6, a comparison device (US) 7, a register of the LFM standard (RLCHM-E) 8, a time delay meter (IVS) 9, a correction signal conditioner Synchronization (FSKS) 10, register in constant constants - propagation times of a signal from each station (RVC) 11.

 The user device (Fig. 3) includes a series-connected receiving antenna, a radio receiving device (RPU) 12, a signal storage device (NS) 13, a comparison device (US) 14, a time delay meter (IVS) 15 signal arrival, a coordinate calculator (VK) 16 , location indicator (IMP) 17, the register of the chirp standard (RLCHM-E) 18, the register of time constants (RVK) 19, the register of coordinates of the emitting stations (RC) 20. The blocks are synchronized by a timer-synchronizer (TC) 21. In this case 3n outputs of the coordinate register 20 are connected to the second inputs of the transmitter 16, n output storage 13 n are connected to first inputs of comparator 14, the second n inputs are connected to the register 18, the reference chirp, the comparator n outputs are connected to first inputs of measuring delay 15, the second inputs of which are connected to the n outputs of the register 19, the time constants.

 The method of radio navigation and the operation of the radio navigation system is as follows.

 From the outputs of the master oscillator 1, the signals (carrier frequency 80 kHz) are fed to the input of the clock clock unit 5, which is a 1: 1000 frequency divider and a clock shaper, as well as to the input of the LFM modulator 3 as the carrier frequency. Clock pulses with a frequency of 80 Hz are fed to the input of the encoder 2, which generates a low-frequency signal-code, individual for each station and determines the sequence, moment and duration of radiation. From the control output of the encoder 2, the signal code is fed to the controlled input of the power amplifier 4. From the output of the modulator 3, the LFM signal, synchronized by the clock, is fed to the signal input of the power amplifier 4, which amplifies and passes it for a time interval equal to the signal code. From the output of the amplifier 4, the signals are fed to a radio-emitting antenna and emitted into space.

 At the same time, the LFM-modulated encoded high-frequency signals of each station are fed to the receiving antennas of the remaining n-1 stations and RPU 6. From the low-frequency outputs of the RPU, the signals are fed to one of the signal inputs of the DC 7, the second signal input of which serves the LFM standard from register 8. V the comparison device 7 receives signals equal to the difference in the arrival times of each frequency component of the chirp signal relative to the standard, these signals are fed to the time delay meter 9, in which the average arrival delays of the signals about each station. These delays are fed to the n-1 inputs of the synchronization correction signal generator 10, to the second n-1 inputs of which the time constants from the RVC register 11 are supplied, from the output of the driver 10 the generalized correction signal is fed to the controlled input of the clock clock unit 5, thereby implementing a frequency time binding the start of radiation of each station in the network of stations.

 Thus, they create a single radio navigation field, which is a set of successive radiation pulses of all stations and excluding their superposition throughout the region.

The sequence of chirp signals from all stations is received at the antenna and RPU 12 of the user device, from the output of which the signal is fed to drive 13, where the sequence of signals is distributed into n cells corresponding to n stations. From the n outputs of the drive 13, the signals accumulated during m cycles, which increases the signal-to-noise ratio by a factor of m ² , are fed to the first inputs of the comparison device 14, to the second inputs of which are supplied from the register of the chirp standard 18. The device 14 determines the delay times t _{n the} received signals relative to the reference. From the outputs of the comparison device 14, the signals corresponding to the measured arrival times are fed to the first inputs of the time delay meter 15, to the second inputs of which from the register of time constants 19 they supply signals corresponding to the propagation times of the signals between each pair of stations. From the outputs of the TDI 15, the signals corresponding to the propagation times of the signals from each station to the place of reception are fed to the first inputs of the coordinate calculator 17, to the second 3n inputs of which signals, corresponding to the coordinates of n radio-emitting stations, are supplied from the coordinate register 20. Using the timer-synchronizer 21 synchronize the operation of all units of the device. From the outputs of the calculator 16, the signals corresponding to the coordinates of the receiving location are fed to the location indicator 17, where they are displayed both in digital form and in the form of a brightness mark on the electronic map.

 The operability of the system was confirmed using hardware-software modeling, which allowed to simulate a regional radio navigation system, for example, for Kazakhstan, see figure 1, the territory of which can be covered by an optimal network of seven stations. The receiving and emitting part of the beacon stations and the user device were made in the form of a model of typical electronic devices and an IBM PC-486 computer.

 The use of linear frequency modulation reception and the formation of a correction signal from time shifts of each frequency component of the signal made it possible to tightly synchronize the operation of the entire network of stations and increased the system's resistance to narrowband interference.

Claims (2)

 1. The method of radio navigation, which consists in the fact that the regional radio navigation field is created by synchronized radio emission from a network of n stations, the radiation of each station is encoded to identify it at the receiving location, the sequence, time points and frequency of sending radio emission pulses are synchronized at the receiving location, the coordinates of which must be determined receive coded emissions from all stations, identify the stations, the received signals are accumulated during m cycles of sending signals from each station, measured in time delays of arrival of each nth signal, determine the propagation time of signals from four stations with the highest signal levels, calculate the distances to these stations and calculate the coordinates of the receiving location using the known coordinates of the stations, characterized in that the radio navigation field is created by synchronized radiation of linearly-frequency-modulated (LFM) signals, at each station these signals are received, time delays of each frequency component of the LFM signals from the remaining n-1 stations relative to the LFM standard are measured and stored at each station and used to modulate its own radiation, taking into account the measured time delays and known time constants - the propagation time of the signal from the other n-1 is adjusted to synchronize stations each station.  2. Regional radio navigation system, including n synchronized ground-based radio emitting stations, each station contains a master oscillator, the outputs of which are fed to the input of the clock clock block and the modulator input, clock pulses from the clock clock block are fed to the encoder input, the signal is fed from the encoder control output to the controlled input of the power amplifier, from the output of the modulator, the signal is fed to the signal input of the power amplifier, from the output of which the signals are fed to the radio-emitting antenna The high-frequency signals of each station are supplied to the receiving antennas of the remaining n-1 stations and a radio receiving device (RPU) for receiving signals from radiating stations, a plurality of user devices, including a series-connected receiving antenna, a radio receiving device, a signal storage device, a comparison device, a time delay meter of signal arrival , a coordinate calculator and a location indicator, while 3n outputs of the coordinate register of the emitting stations are connected to the second inputs of the coordinate calculator nat, the second n inputs of the comparison device are connected to the code standard register, the second inputs of the signal arrival time delay meter are connected to the n outputs of the signal propagation time constant-time register between each pair of stations, and all the blocks are synchronized by a timer-synchronizer, characterized in that in each the station modulator is designed as a linear frequency-modulated (LFM) modulator, and the demodulator in the radio receiver of each station and user device is configured as a LFM demodulator, each A register of the LFM standard, the register of time constants, a device for comparing the LFM signal and the LFM standard, a time delay meter and a generator of the synchronization correction signal are entered at the station, while signals from the low-frequency outputs of the RPU are fed to one of the signal inputs of the comparison device, to the second signal the input of which is supplied by the LFM standard from the register of the LFM standard, from the comparison device the signals are sent to a time delay meter, the arrivals delays of signals from which are fed to the (n-1) inputs of the signal generator synchronization signals, to the second (n-1) inputs of which time constants are supplied from the register of time constants, from the output of the synchronization correction signal generator, the correction signal is supplied to the controlled input of the clock clock block, and in each user device, the code standard register is executed as a register of the chirp standard .

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