RU2097780C1 - Radio-navigational system (bagis-a) - Google Patents

Abstract

FIELD: radio- navigational systems intended for solution of complex problems of short-range navigation. SUBSTANCE: it is a pulsed-phase locked system using the principle of retransmission of the reference signal by a well regulated station network with fixed coordinates. The system algorithm, structural realization of stations and receivers-computers combined with movable objects make it possible to obtain high accuracies of coordinate measurement at instabilities of reference generators Δf/f = 10^-8, excluding static and random errors caused by: - time delay of detection of the reference signal; - time instability of retransmission delay; - space fluctuation of the radio wave phase. It is provided by formation of two frequencies that are radiated on the air successively in time in the active mode of station operation. According to the results of measurement of time intervals between reference signals, the receivers - computers determine the ranges to the reference stations that are converter to the coordinates of the point of reception of signals. The radio-navigational system provides for: - all-weather operation and servicing of an unlimited number of system users; - continuous automatic estimation of the point coordinates, simplicity of servicing and information pick-up; - pilotless pilotage of ships in a complex fairway and registration of its precision; - arrangement of global networks enveloping large territories, and structures of limited access; - high accuracy and reliability of measurements; - low equipment cost and minimum servicing expenses, operatorless mode of operation. EFFECT: enhanced efficiency. 3 cl, 7 dwg

Description

 The invention relates to radio navigation systems (RNS), designed to determine the coordinates of the place of moving objects.

The purpose of measurements is to increase the safety of pilotage in the coastal strip, rivers and narrow canals, flights along difficult routes, etc. RNS are divided [1] into long-range navigation systems (for example, Laurent-A, Laurent-S, Omega), middle (Deca, Pier-1) and near. Satellite radio navigation systems (SRNS) are becoming more widely used, which are distinguished by the fact that their reference points are not fixed on the earth's surface, but naturally move in near-Earth space (Transit, Navstar). The mentioned systems belong to widely used hyperbolic RNS, which are classified by the method of determining the navigation parameter:
phase, using the dependence of the phase of the carrier oscillations on distance (Deca, Omega);
pulsed (temporary), using the dependence of the duration of propagation of radio waves from distance (Laurent-A);
frequency, using the dependence of the frequency of the carrier or modulated oscillations on the rate of change of distances (Transit, Navstar).

The essence of the hyperbolic method is the measurement at the point of reception of the difference in distances or phases from the coherent sources of two reference stations. The difference in these parameters reveals the contour of the position hyperbola. Having performed similar measurements for the other two stations, two hyperbolas and more are obtained. At the point of their intersection, the place of the vessel is determined: by table-graphic method or by means of special radio navigation charts. The synchronism of all reference stations in phase and time of signal emission is relative to universal time. The accuracy of the final measurements in many cases is much lower than the potential accuracy of the used RNS due to a number of factors that are difficult to take into account:
the conditions for the propagation of surface and spatial radio waves at different times of the day (at night the errors increase by 2-8 times) and the complexity of their separation;
the dependence of the distance from the reference station (with an increase in the range of 2–3 times, the mean square errors increase 5–10 times) [1, p. 213]
deviations of the propagation velocity of radio waves from the nominal depending on the underlying surface.

 The ratio of the energy of surface and spatial radio waves, where the latter are a destabilizing factor, is one of the main sources of error. A tendency towards a decrease in the frequency of radio emissions (for example, in the Omega RNS operating frequencies of 10–14 kHz) is associated with this, providing greater stability of the surface radio waves, to which all radio navigation maps and tables are oriented. The above instabilities that limit the accuracy of coordinate measurements are eliminated by means of numerous corrections set forth in specialized tables and reference books. The choice of the correct type of correction presents significant difficulties, which is the cause of systematic errors in determining the location. The disadvantages of the known systems (in relation to the complex tasks of near navigation) include: 1) low accuracy and reliability of determining the location; 2) the need for special maps and tables, the complexity of analytical calculations; 3) low frequency of measurement repeatability; 4) the stationarity and high cost of unified synchronization equipment, which does not allow optimally, based on the specifics of the route, to place the required number of reference stations; 5) limited capabilities of known RNSs due to the algorithmic division into masters and slaves (with the exception of the Omega RNS), which do not allow the difference in oscillations of any stations to be used to measure (in order to increase the number of position lines); 6) vulnerability of systems and limited access in the event of a military conflict.

Taking into account these shortcomings, we formulate the basic requirements for promising RNS:
weatherproof;
meeting the needs of an unlimited number of users;
high accuracy and reliability of measurement results;
continuous automatic observation of the ship's place, ease of maintenance and volume of information;
mapping the ship’s position directly in geographical coordinates, which will allow you to do without specialized radio navigation maps and tables;
the possibility of pilotless automated pilotage and documentation of its accuracy;
modularity of RNS elements, which allows to compose both global networks and limited-use structures (closed from unauthorized access);
low hardware cost and minimal operating costs.

The above list of requirements is partially provided by known systems. RNS, designed to solve complex short-range navigation problems, according to the principle of action, refers to pulse-phase systems. The same principle is implemented in the RNS Laurent-S, used as a prototype. The Laurent-S RNS chain consists of one master and three to four slave stations. All stations operate at the same frequency f 100 kHz, the radio waves of which propagate well along the earth's surface. The master station emits signals periodically with a strictly synchronized frequency. Slave stations receive these signals and, with well-defined delays (for each slave), emit their signals. The work of the Laurent-S RNS is based on measuring at the point of reception the time interval between the moments of arrival of the pulses from the master and slave radio emitters and the phase difference of the high-frequency oscillations filling the pulses. The pulse method of measuring the difference in distances is used to roughly determine the position of the vessel and eliminate ambiguity, and the phase method is used to determine the position lines with high accuracy. An integer number of periods of the carrier frequency is determined uniquely if the measurement error Δt _{and the} pulse method (along the envelope) is less than ± 0.5 • T, which will be Δt _and 5 μs [1, p. 217] That is, to resolve the ambiguity, a single pulse is used, subject to interference. According to all the canons of the theory and practice of statistical tests, the confidence probability of such an estimate is very low. In addition, the above list of disadvantages of known RNS applies to Laurent-C.

 Thus, none of the known RNS provides acceptable security for the near navigation of moving objects on complex routes.

 The goal is implemented by the RNS, consisting of an ordered network of relay stations with fixed parameters and computer receivers combined with moving objects. Each station contains a series-connected antenna unit, a first switch connected to a power amplifier by a second input, a matched radio receiver and an information parameter input unit connected to a first synchronizer output by a second input. The second synchronizer output through the serially connected block of service signal parameters, the second switch connected to the third output of the synchronizer by a second input, the coding unit and modulator, and the second input through the first discrete frequency divider connected to the output of the stable frequency generator. The output of the first discrete frequency divider is simultaneously connected to the first input of the synchronizer, the fourth output of which through a counter and decoder connected in series is connected to the second input of the synchronizer, the fifth output connected to the third input of the first switch. The second input of the counter and the third input of the synchronizer are connected to the output of the pulse shaper of the account. In addition to the output of the stable frequency generator, connected in series are a phase correction block, a second discrete frequency divider, a phase discriminator, a second input connected to the output of the first switch through an active bandpass filter, and a key connected to the second input of the phase correction block by the output. The output of the second discrete frequency divider is simultaneously connected to the input of the pulse shaper of the account and through the third switch, the second and third inputs connected respectively to the output of the modulator and the sixth input of the synchronizer is connected to the input of the power amplifier. In this case, the output of the phase discriminator through a series-connected ADC and the first register, the second input connected to the seventh output of the synchronizer, is connected to the third input of the second switch, the fourth input of which is through the shaper of the variable parameters, the second input connected to the eighth output of the synchronizer is connected to the output of the informative input unit parameters. The second key input and the third input of the first register are connected to the ninth output of the synchronizer, the fourth input of which is connected to the detector of service signals by the input of the matched radio receiver connected to the output, simultaneously through the comparison circuit of the second input connected to the output of the second register connected to the fifth input of the synchronizer.

 The receiver of the RNC computer contains a series-connected antenna unit, a matched radio receiver, a block of constant storage registers, a second input connected to the first output of the synchronizer, a range calculator, a second input connected to the second output of the synchronizer, a coordinate calculator and a coordinate fixation unit. The second output of the synchronizer is simultaneously connected to the second input of the coordinate calculator and to the first input of the station selection optimizer, the second input connected to the output of the range calculator. The first output of the station selection optimizer through the first block of registers is connected to the third inputs of the coordinate calculator and range calculator, the fourth input of which is connected through the second block of registers and the counter of time intervals in series to the output of the stable frequency generator, simultaneously connected to the first output of the synchronizer. The output of the matched radio through the code comparison unit is connected to the second input of the synchronizer, the third output of which is connected to the second input of the synchronizer, the third output of which is connected to the second input of the second block of registers. The second and third outputs of the station selection optimizer are respectively connected to the second input of the code comparison unit and the station parameters memory block, the second input connected to the fourth output of the synchronizer, and the output to the third input of the station selection optimizer and the second input of the first register block. An active bandpass filter and a phase discriminator are connected in series to the output of the antenna unit, connected to the output of a discrete frequency divider with a second input, the output of which is connected through a series-connected reset pulse generator and logic circuitry to the second input of the time interval counter and to the third input of the second register block. Additionally, the output of the coordinated radio receiver through the detector of service signals is connected to the third input of the synchronizer and through the third block of registers, the second input connected to the fifth output of the synchronizer, is connected to the fifth input of the range calculator. The phase discriminator output is connected to the ADC and the fourth block of registers connected in series, the second input is connected to the sixth output of the synchronizer, and the output of the fourth block of registers is connected to the sixth input of the range calculator. Serially connected keys and a phase correction unit connected between the output of the stable frequency generator and the input of the discrete frequency divider are connected to the output of the phase discriminator. The second inputs of the key and the logic circuit And are connected to the seventh output of the synchronizer, the eighth output of which is connected to the third input of the logic circuit I. The output of the reset pulse generator is connected to the fourth output of the synchronizer and through the second counter connected in series, the second input connected to the ninth output of the synchronizer, and a decoder connected to the fifth output of the synchronizer.

In addition, the range calculator by an additional input is connected to the output of the coordinate fixation unit, and the additional inputs of the coordinate and range calculators are connected to the signal source H _o .

In FIG. 1 is a functional diagram of a reference station (1 antenna unit, 2 first switch, 3 power amplifier, 4 matched radio receiver, 5 information parameter input unit, 6 synchronizer, 7 service signal parameter block, 8 second switch, 9 coding block, 10 modulator, 11 first discrete frequency divider (f _h ), 12 stable frequency generator, 13 counter, 14 decoder, 15 count pulse generator, 16 phase correction unit, 17 second discrete frequency divider (f _o ), 18 phase discriminator, 19 active band-pass filter (frequencies F _o ) , 20 key, 21 third switch, 22 analog-to-digital converter (ADC), 23 first register (phase misalignment storage), 24 variable parameter generator, 25 - signal detector, 26 comparison circuit, 27 second register (station code storage)).

Variants of the "sweep" of the reference stations are shown in FIG. 2, where a is the long track, into the areal track. Here t $\genfrac{}{}{0ex}{}{\text{,}}{\text{PA}}$ , t $\genfrac{}{}{0ex}{}{\text{,}}{\text{Ab}}$ , t $\genfrac{}{}{0ex}{}{\text{,}}{\text{BD}}$ times the front of the radio wave travels the base distances between the reference stations, and Δt _p , Δt _a , Δt _b , Δt _{d are the} times the front of the radio wave travels distances from the object C to the corresponding reference stations.

In FIG. Figure 3 shows the functional diagram of the receiver-computer of the RNS (28 antenna unit, 29 matched radio receiver, 30 block of constant storage registers, 31 synchronizer, 32 range calculator, 33 - coordinate calculator, 34 coordinate fixation unit, 35 station selection optimizer, 36 first register block ( storage of parameters of reference stations), 37 second block of registers (storage of time intervals of measurement), 38 counter of time intervals, 39 generator of stable frequency, 40 block of comparison (station codes), 41 block of memory of parameters of stations, 42 active olos frequency filter F _o , 43 phase discriminator, 44 - discrete frequency divider f _o , 45 reset pulse shaper, 46 logic I, 47 detector of service signals, 48 third block of registers (storage of basic residuals of reference stations), 49 analog-to-digital converter (ADC), 50 fourth block of registers (storage of phase residuals of the receiver-calculator), 51 keys, 52 phase correction block, 53 second counter, 54 decoder).

 The voltage diagram of the active "transmission" mode is shown in FIG. 4.

In FIG. Figure 5 shows one of the options for the structure of the time reference to the frequency f _o shown by the dashed line that make up the information and radio messages.

A demonstration plot showing the temporal relationships at the reference points P, A, B, D and the measurement site C (X _o , Y _o ) is shown in FIG. 6. Here t $\genfrac{}{}{0ex}{}{\text{b}}{\text{PA}}$ , t $\genfrac{}{}{0ex}{}{\text{b}}{\text{Ab}}$ , t $\genfrac{}{}{0ex}{}{\text{b}}{\text{BD}}$ radio wave base distance travel time; τ _ass const - fixed relay delay; Δt _p , Δt _a , Δt _b , Δt _d travel time of the radio wave distance from the object to the corresponding reference station; T $\genfrac{}{}{0ex}{}{\text{o}}{\text{one}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{2}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{3}}$ measured at the receiving site C parameters.

 In FIG. Figure 7 shows voltage plots explaining the operation of blocks of reference stations B, D and receiver-calculator C (a, b, d signals in the zones of reference stations A, B, D; c signals at the receiving location C; g graphical display of the state of counter 13 (art. . B); l voltage at the output of the phase discriminator 18 (Art. B); k key control signal 20 (Art. B); m - trigger for detecting code detection (as part of synchronizer 6 art. B); j - mode switching trigger " Reception-Transmission "(as part of the synchronizer st. B); key control signal 20 (st. D); o voltage at the output of the phase discriminator 18 (s t. D); p trigger for detecting code detection (as part of the synchronizer, Art. D); r key control signal 5 (receive. C); z - voltage at the input of phase discriminator 43 (receive. C); s graphic display of the state of the second counter 53 (receive. C); v graphical display of the status of the counter 38 time intervals (receive. C).

 When developing the system, we proceeded from two fundamental concepts: 1) minimizing the number of various amendments to determine the position of the vessel up to their complete exclusion; 2) the range of reference stations (zone of reliable service) should not exceed the values that provide the required accuracy of solving the main problem, regardless of the time of day or random factors.

 These provisions, limiting the maximum permissible distance between the reference station and the object, establish that, to ensure accurate navigation, the number of reference stations must be large, and their location must be determined by the specifics of the problem being solved. In this case, the profitability of using RNS can be justified by its high efficiency at low hardware and operating costs. The latter are provided only with the unconditional rejection of an expensive unified synchronization system, avoiding unjustified complications, and a significant reduction in the nominal power of the station. The logical rationality of the system is determined by the specifics of short-range navigation tasks, where regulated areas of action are quite clearly limited. For example, a narrow coastal strip of a sufficiently large length, air fleet routes in rough terrain or in the concentration zone of high-altitude objects, river waterways are typical cases of long routes with a complex configuration.

 In the RNS, the principle of signal relaying by low-power stations is used, which ensures targeted expansion of the area (extended or areal) of the functioning of the system (Fig. 2). In this case, the destabilizing effect of spatial radio waves is practically eliminated due to the relatively small distances, the presence of a delay time in relaying and discreteness of radiation. The relay route can be set by the internal programs of the station or by the dispatcher station, which has a communication channel with a personal computer that provides system start-up, operation monitoring and control (route correction). The reference signal on an extended path can be unidirectional or reversed (continuously or with a given discrete) at the ends of the path, providing the dispatcher with information about the operation of the system.

The main blocks of the RNS are stable frequency generators. In [2], the structures of thermostated quartz oscillators with a PLL ring are presented, which provide frequency instability Δf / f _r 10 ^-9 - 10 ^-11 . Higher stability (10 ^-12 10 ^-14 ) is realized by various types of quantum generators. The system algorithm, structural implementations of reference stations and computer receivers having many identical blocks (for ease of perception, the block numbers of the receivers will be indicated in brackets) allow for instabilities of generators 12 (39) Δf / f _r 10 ^-8 to obtain high measurement accuracy, minimizing static and random errors due to:
time delay of the reference signal detection;
temporary instability of relay delay;
spatial fluctuations of the radio wave phase.

This is ensured by the formation of two frequencies: reference f _o (measuring) and carrier f _h (information). The reference frequency f _o is allocated at the output of the second discrete divider 11, where f _h (10 ¹ 10 ⁴ ) • f ₀ . The implementation of discrete dividers 11, 17 (44) on hard digital logic (counters) provides temporary stability of the adopted frequency ratio. The relay route station alternately (in accordance with the address indication) from the “Reception” passive mode switches to the “Transmission” active mode (Fig. 4), sequentially broadcasting the reference cleanliness f _o and radio broadcast information with carrier frequency f _{h in time} . The switching of modes is provided by the third switch 21, controlled by the synchronizer 6. The frequency f _{o of the} active station in the time interval t ₁ -t ₂ radiation is taken as the time standard F _o relative to which the blocks 16 of the passive stations and the corresponding blocks (52) of the receiver-calculators located in reach zone, adjust the phase of the internal reference frequencies f _o . The duration of the correction interval (t ₁ -t ₂ , Fig. 4) is determined by the nominal speed of the auto-tuning circuit. The active station sets the correction interval τ _KF equal to an integer number of periods of the reference frequency M • T _o fixed at the corresponding output of the decoder 14. The phase mismatch with respect to the frequency F _{o of the} time standard from the outputs of the bandpass filters 19 (42) is extracted by phase discriminators 18 (43), and the time gating by keys 16 ( 51) controlled by synchronizers 6 (31). It is easy to provide key management 16 (51) by the condition of target (selective) gating. This avoids integer phase correction errors in the stationary relay cycle, due to the restrictions imposed by a fixed time interval of auto-tuning. A priori information about the value of M allows the blocks of synchronizers of passive stations and receiver-calculators to eliminate a malfunction in the system by prematurely interrupting the correction mode (closing keys 16, 51). The real option is to set a safe correction interval by counting the number of cycles (periods) at the outputs of the bandpass filters 19 (42). In synchronizers 6 (31), logic signals are generated to prohibit the continuation of the analysis if the coding address (t ₂ -t ₃ , Fig. 5) of the input radio message does not match the expected (or expected for receiver-calculators). In the "Transmission" mode at a temporary t ₂ -t ₄ (Fig. 4) with a carrier f _{h, the} frequency f _o provides a tough time reference for the information and radio transmission of fixed activity (τ K • T _o , where K is an integer). One embodiment of the structure and timing of the reference frequency f _o is shown in FIG. 5. By combining the time boundaries of the components of the radio package with a fixed phase (0 ^o , 180 ^o ) of the reference frequency f _o (highlighted in dashed lines in Figs. 4 and 5), the stability of the formation and reading of information is achieved. The hardware simply enough provides a fixed time shift of the beginning of formation t _{3 of the} information and radio message from the moment t _{2 of the} carrier frequency f _{h is} turned _on . This makes it possible to exclude the influence of transients in the circuits of matched radio receivers 4 (29) on the assessment of the detection of the pilot signal of the radio transmission. It is not ruled out that it is possible to add additional information to informational radio packages, for example, station's own parameters (code, coordinates), coding quantities, etc. This is facilitated by a system algorithm that does not limit the frequency ratio f _h / f _o , on which the information capacity of a fixed time duration t depends. Information about the station code is stored in the second register 27. By introducing additional links, it is possible to change the station code by the dispatcher if it becomes necessary to restrict or block access to the system. Together, the comparison circuit 26 and the synchronizer 6, which analyzes the signal of the block 26 at the time interval t ₂ t ₃ (Fig. 5), recognizes the received code. In the active mode, when the input of the matched receiver 4 of the station is blocked, zeroing of the counter 13 is carried out by the synchronizer 6 at the moments of fixing the digital codes of numbers M and (K + z). Thus, the duration of the "Transmission" mode is determined by the condition: t _ass. (К + Z + M) • Т _о , where z is a number (0, 1, 2, 3,), which determines the time shift of the beginning of the information broadcasting. The "Transmission" mode is provided by the first switch 2: the inputs of the matched radio receiver 4 and the bandpass filter 13 are blocked, and the signal from the power amplifier 3 enters the antenna unit 1.

A priori information about the duration of the pilot signal (τ _ps ) and the timing of its fronts to the fixed phases (0 ^o , 180 ^o ) of the reference frequency f _o significantly simplifies the requirements for the implementation of a compatible radio receiver 4 (29) and detector 25 (47) . The structure of the latter is also simplified by the fact that information on the sequence number of the cycle (period) of the reference signal f _o taken from the output of the decoder 14 (54) is received from the synchronizer 6 (31). As a result of this, an error of fixation of the pilot signal by the detector 25 (47) is allowed within the entire pulse (at τ _ps T _o ). A priori information about its time reference enables the synchronizer 6 (31) to use for accurate fixation a pulse coinciding in time from the output of block 15 (45). Increased accuracy is ensured by fixing and subsequent accounting in the coordinates X _o , Y _{o of the} object of the phase “residual” of the frequencies f _{o of the} reference stations (τ $\genfrac{}{}{0ex}{}{\text{A}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{B}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{D}}{\text{f}}$ ,) and phase “discrepancies” of the frequency f _{o of the} receiver-computer with reference stations (τ _fA , τ _fV , τ _fD ,). Here, the letter symbols reflect the affiliation of stations A, B, D, according to FIG. 2. The final time (τ _f ) of the phase residual (τ _f = ∓Φ _n • T _o / 360 ^o is fixed in the corresponding registers of blocks 23 (50) after conversion to digital code by ADC blocks 22 (49). The number of cycles (periods ) the frequency F _o allocated for averaging the result of the phase discriminators 18 (43) provides high confidence of the estimate. When forming the information radio package in the "Transmission" mode, the numerical value ± τ _f recorded in block 23 is "packed" into the corresponding time by switching the second switch 8 strobe contents ko the receiver-calculators (Fig. 3) are fixed in the registers of block 48.

The digital presentation of information allows you to choose the optimal method of encoding 9 (for example, a serial code, Manchester code, etc.). In our opinion, the double Manchester code is preferable, which does not change the constant component of the signal with any combination of output information. By including the corresponding nodes in the composition of the coordinated radios 4 (29), decoding of the input signal is provided. Specific moments imposing restrictions are not ruled out, as a result of which the conversion coefficients of the coding and decoding units must be taken equal to 1. Taking into account the saturation of the ether with interference, the noise immunity of the information radio channel is preferably ensured by using frequency modulation in block 10 if the problem being solved does not impose specific restrictions on the type of modulation . In this case, the reference frequency f _o used for phase measurements is not modulated.

The functional diagram of the receiver-computer (Fig. 3) has many common blocks (28, 29, 39, 42, 43, 44, 45, 47, 49, 51, 52, 53 and 54) with the structure of the station (Fig. 1). This allows you to reduce the description of the work with links to the above text. Information about the binding parameters of all stations of the relay route, stored in the memory block 41 of the receiver-calculators, is selected as necessary in the first block of registers 36 by forming the corresponding addresses of the memory cells 41. The parameters of the binding stations include their coordinates on the ground X, Y and antenna heights H. The values of the latter are composed of two components: the geodetic heights of the place and the heights of the installation of transceiver antennas. In real conditions, in addition to visual indication of the calculated coordinates of the object X _o , Y _o , it is desirable to display the codes of the reference stations from the block of registers 36. In difficult conditions, this provides additional control over the reliability of the receiver-calculator.

Аналогично вычисляются t $\genfrac{}{}{0ex}{}{\text{б}}{\text{РА}}$ , t $\genfrac{}{}{0ex}{}{\text{б}}{\text{ВD}}$
Решение задачи будем искать через вычисление дальностей S_a, S_b, S_d от объекта C (X_o, Y_o, H_o) до опорных станций A, B, D. При фиксированной скорости распространения pадиоволны V_p/в величины дальностей зависят от Δt_p, Δt_a, Δt_b, Δt_d времен прохождения фронта pадиоволны от объекта до соответствующих опорных станций P, A, B, D.We define the algorithmic and analytical relationships that can be embedded in the structures of specialized blocks 32, 33. The solution to the problem is simplified by using the calculation apparatus on a plane, not on a sphere. Such a simplification is permissible, based on the introduced restriction, near navigation. We define the initial data of the problem using, for clarity, FIGS. 2 and 6: 1) the known parameters of reference stations A (X _a , Y _a , H _a ), B (X _b , Y _b , H _b ), D (X _d , Y _d , H _d ), P (X _p , Y _p , H _p ) and the value of H _{o the} receiver-transmitter; 2) measurement results by the receiving system of time intervals T $\genfrac{}{}{0ex}{}{\text{o}}{\text{one}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{2}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{3}}$ between reference signals; 3) phase "residuals" fixed in the receiver τ $\genfrac{}{}{0ex}{}{\text{A}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{B}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{D}}{\text{f}}$ reference stations and phase "residuals" τ _fA , τ _fV , τ _{fD of the} receiver with respect to stations A, B, D, respectively; 4) a priori algorithmic information about the quantities; τ _ass const, V _p / at 3 • 10 ⁵ km / s, T _r = const-discrete time standard; 5) times t $\genfrac{}{}{0ex}{}{\text{b}}{\text{PA}}$ , t $\genfrac{}{}{0ex}{}{\text{b}}{\text{Ab}}$ , t $\genfrac{}{}{0ex}{}{\text{b}}{\text{BD}}$ the passage of the radio wave base distances, which are calculated with the known parameters of the reference stations. For instance,

Similarly, t $\genfrac{}{}{0ex}{}{\text{b}}{\text{RA}}$ , t $\genfrac{}{}{0ex}{}{\text{b}}{\text{BD}}$
We will seek a solution to the problem by calculating the ranges S _a , S _b , S _d from the object C (X _o , Y _o , H _o ) to the reference stations A, B, D. For a fixed propagation velocity of the radio wave V _{p / in the} range values depend on Δt _p , Δt _a , Δt _b , Δt _{d of} the propagation times of the front of the radio wave from the object to the corresponding reference stations P, A, B, D.

Здесь мы имеем систему из трех уравнений при четырех неизвестных, которая напрямую не может быть решена. В выражении (1) изначально неопределенной величине Δt_p придается нулевое значение. Неопределенность Δt_p вполне естественна, так как вычислитель не имеет временной опорной точки (отсутствие синхронизации с моментом pадиоизлучения станции P). Задача решается методом последовательного приближения (итераций). Вычислительное загрубление начальным условием Δt_p 0, дающее приблизительные координаты

объекта, в последующих циклах измерений устраняется, так как Δt_p вычисляется корректором приемника:

а результат подставляется в соответствующие выражения. Неопределенность Δt_p автоматически устраняется, когда из трех опорных станций создается замкнутый цикл ретрансляции сигнала. Использование

является спецификой предложенного решения, которое не является единственно возможным, а потому этот частный случай вынесен в п.3 формулы.We write the system of equations relating the reduced time parameters

Here we have a system of three equations with four unknowns, which cannot be directly solved. In expression (1), an initially undetermined quantity Δt _{p is} assigned a zero value. The uncertainty Δt _p is quite natural, since the computer does not have a temporary reference point (lack of synchronization with the moment of radio emission of station P). The problem is solved by the method of successive approximation (iterations). Computational coarsening by the initial condition Δt _p 0 giving approximate coordinates

object in subsequent measurement cycles is eliminated, since Δt _{p is} calculated by the corrector of the receiver:

and the result is substituted into the corresponding expressions. The uncertainty Δt _{p is} automatically eliminated when a closed signal relay cycle is created from the three reference stations. Using

is the specificity of the proposed solution, which is not the only possible one, and therefore this particular case is presented in paragraph 3 of the formula.

Тогда система уравнений (1)-(3) будет иметь вид:

Отсюда найдем временные величины удаленности от опорных станций:

Преобразуем временные величины Δt_a, ΔT_b, Δt_d в метрические S_a, S_b, S_d удаленности от опорных станций:

Запишем систему уравнений модулей прямых, проведенных через две точки (параметры объекта и опорной станции):

где
ΔH_a = H_o-H_a, ΔH_b = H_o-H_b, ΔH_d = H_o-H_d.
Из этой системы (13) определим значения X_o, Y_o. Опуская промежуточные выкладки, запишем:

где
K₂ = S $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ -S $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -X $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ +X $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -Y $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ +Y $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -ΔH $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ +ΔH $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ ; (17)
Определив численное значение Y_o, подставим его в выражение (14) и вычислим значение X_o.Combine all the known parameters of equations (1) - (3), respectively designating them by t $\genfrac{}{}{0ex}{}{\text{Σ}}{\text{A}}$ , t $\genfrac{}{}{0ex}{}{\text{Σ}}{\text{B}}$ , t $\genfrac{}{}{0ex}{}{\text{Σ}}{\text{D}}$

Then the system of equations (1) - (3) will have the form:

From here we find the temporary distance from the reference stations:

We transform the temporary values Δt _a , ΔT _b , Δt _d into metric S _a , S _b , S _{d the} distances from the reference stations:

We write the system of equations for the modules of lines drawn through two points (parameters of the object and reference station):

Where
ΔH _a = H _o -H _a , ΔH _b = H _o -H _b , ΔH _d = H _o -H _d .
From this system (13) we determine the values of X _o , Y _o . Omitting the intermediate calculations, we write:

Where
K ₂ = S $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ -S $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -X $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ + X $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -Y $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ + Y $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ -ΔH $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ + ΔH $\genfrac{}{}{0ex}{}{\text{2}}{\text{b}}$ ; (17)
Having determined the numerical value of Y _o , substitute it in expression (14) and calculate the value of X _o .

The above expressions reflecting the sufficiency of conditions for calculating the coordinates of the object X _o , Y _o in a rectangular orthodromic coordinate system is only one of the solutions (possibly not the most optimal from the position of minimizing the computational process). Known transformations [1, p. 213] provides a transition to geographical coordinates. The bulkiness of computational formulas creates the undoubted complexity of their hardware. The optimal solution is microprocessor based software implementation of calculations. The transmitter 32 of the ranges S _a , S _b , S _d and the calculator 33 of the coordinates X _o , Y _o , whose inputs are connected with the blocks of the source data, are functionally allocated in the structure of the receiving device. In accordance with the above expressions, this is a block of memory 41 parameters of stations, the second block of registers 37 for storing measurement results (T $\genfrac{}{}{0ex}{}{\text{o}}{\text{one}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{2}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{3}}$ ), the third block of registers 48 for storing phase residuals of reference stations (τ $\genfrac{}{}{0ex}{}{\text{A}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{B}}{\text{f}}$ , τ $\genfrac{}{}{0ex}{}{\text{D}}{\text{f}}$ ) the fourth block of registers 50 for storing phase residuals of the receiving device τ _fA , τ _fB , τ _fD and the first block of registers 36 for storing the parameters of the stations P (X _p , Y _p , H _p ), A (X _a , Y _a , H _a ), B (X _b , Y _b , H _b ) and D (X _d , Y _d , H _d ) involved in the computational cycle. The calculation of intermediate values and components of the final formulas is carried out in the “body” of the said blocks 32, 33. A system failure due to the high refresh rate of the input information compared to the calculation speed is not difficult to exclude by blocking the output signal of the comparison block 40 until the completion of the full cycle of coordinate calculations. There is a fairly wide range of tasks where the differences in the heights of the antennas (reference stations and computer receivers) can be neglected. This allows us to simplify the formula expressions of the coordinate estimate. In the serial production of equipment, a simplified version can be taken as the basic one with an increase in computing power at the request of the consumer. In the receiving device, the optimizer 35 for selecting the reference stations is functionally allocated, which cannot be attributed to the number of required units of the system, since its introduction depends on the specifics of the problem being solved. One of the functions of the optimizer 35 is the formation of the addresses of the cells of the memory unit 41 for the purpose of selecting the parameters of the reference stations according to the codes entered in the comparison unit 40. Optimization refers to the allocation of codes (addresses) of a group of sequentially functioning stations that are least distant from objects and, therefore, ensure conditions of limiting measurement accuracy. Based on the information with the ranges S _a , S _b , S _d relative to the reference stations, it is easy to indicate the corrected group of station codes, which must be identified by fixing the information parameters in the corresponding blocks, by the difference and sign of the extreme values of S _a -S _d Information about the relay route can be laid down in the block of registers 30 storing constants V _{p / in} , τ _ass. T _g .

Measurement of time parameters (T $\genfrac{}{}{0ex}{}{\text{o}}{\text{one}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{2}}$ , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{3}}$ ) has a specificity and requires explanation. The measurement result does not depend on the variations of the reference points within the information radio packages (figure 5). The leading edge t _{6 of} the information content interval is preferable as a reference point, since by this moment reactions to the coincidence (mismatch) of station codes t ₂ -t ₃ and operation code t ₄ -t ₅ will form in the receiver. In this case, the fixation of all informative parameters will only occur when the code of a particular station is recognized (from a sequential row or an optimized sample). By introducing an operation code (measuring, changing the parameters of a system or a specific station, etc.), the adaptability of the system significantly expands, since it becomes possible to enter diverse information into a radio message. A priori information about a fixed time shift relative to the end of the pilot signal by an integer number of periods T _o makes it possible to use clock-matching clock pulses from the output of the shaper 45 and the fixed output of the decoder 54. When the code is recognized, the output signal of block 46 captures the state in the second block of registers 37 counter 38 at the time of reset, which is carried out with a slight delay. The measurement results are converted to time intervals: T $\genfrac{}{}{0ex}{}{\text{o}}{\text{one}}$ = R • T _g , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{2}}$ = R • T _g , T $\genfrac{}{}{0ex}{}{\text{o}}{\text{3}}$ = R • T _g where T _g 1 / f _g the generator period is 39, and R, Q, L is the numerical information of the counter 38 recorded in the corresponding registers of block 37.

Thus, the Bagis-A RS described above potentially provides the ultimate measurement accuracy, limited only by the hardware and computational error of the system components. The time of one measurement cycle depends on the length of the route, the number of relay stations, the reference frequency f _o and the speed of the coordinate computers. We take the path length l = 500 km, which is served by N relay stations. We take the frequency f _o equal to 100 kHz (similar to PHC Laurent-C). Duration τ _ass. limited by the value of τ _ass. P _cycle. • T _o , where P _cyc. - the number of periods allocated to the "Correction" mode and the formation of the radio package. When P _cycle. 100 we have τ _ass. 1 ms At N 50, the total delay Σ _ass. 50 ms The propagation time of the entire wave path is <2 ms. Hence, the refresh rate of the measurement results is ≈ 20 Hz (if the calculation of the coordinates X _o , Y _{o of the} object fits into the interval of 50 ms). At a vessel speed V _{c of the} vessel of 20 km / h, the dynamic error does not exceed 0.5 m. The discreteness of the output information can be smoothed out by switching on the coordinate extrapolation block at the output of the receiver-calculator (the mathematical apparatus of spline functions allows one to describe any trajectory with great accuracy). Let us evaluate the effect on the measurement accuracy of the Doppler frequency shift (DFS): DSP ± f _o • V _c / V _{p /} v ≈ ± 2 • 10 ^-3 Hz.

Then for τ _ass. 1 ms, the temporary instability will not exceed 0.02 ns, which will be only 2 • 10 ^-6 fraction of the period T _o (if the DSL is estimated as instability Δf / f _g 2 • 10 ^-8 ). This value is so small that it practically does not affect the accuracy of measurements. Under these conditions, the nominal power of typical stations should provide a range of ≈ 20 km, which is easily implemented by portable radios with a well-equipped antenna. The receivers-calculators fit into the same dimensions.

From here it is easy to draw conclusions about the real value of the whole complex. The duration error τ _ass. with generator instabilities Δf / f _g 10 ^-8 due to smallness (≈ 0.01 ns) can be neglected. For pilotless pilotage, it is enough to have the coordinates of the reference path of the fairway in the on-board memory devices. In this case, it does not present technical difficulties to document the accuracy of pilotage. Information about the coordinates of the reference trajectory should be provided by a specialized coastal surveillance service, whose inspecting vessel is able, with good visibility, to accurately follow the prescribed channel with fixing the coordinates to magnetic tape or disk. Subsequently, this information, repeatedly replicated, is entered into the electronic memory of the ships.

 Structural implementations of the blocks used do not need explanation. The work of the RNS is clearly illustrated by the voltage diagrams of Fig.7. Ultimate accuracy depends on the sensitivity and linearity of phase discriminators with small discrepancies. Non-linearities with large discrepancies do not introduce errors, since they are worked out by auto-tuning circuits. The output signal of the phase discriminators 18 (43) depends on the amplitude of the input signals; therefore, the implementation of active bandpass filters 19 (42) should ensure the stability of the output signals by introducing AGC nodes (see note).

 Implementations of synchronizer structures 6 (31) are not difficult. For example, one of the options for the structure of the station synchronizer 6 contains 16 AND logic circuits, 2 OR logic circuits, 2 counters, a memory block, a decoder, and 4 triggers. This circuit is cumbersome in electrical representation and is implemented on only 6-8 cases of typical microcircuits.

 NOTE It is quite difficult to ensure a high linearity of the discriminatory characteristics of blocks 18, 43 in the entire range of mismatches, therefore, no option is given that allows the exclusion of phase correction blocks 16, 52 and 20, 51.

Sources of information
1. Leskov M.M. Baranov Yu.K. Gavryuk M.I. Navigation. M. Transport, 1986.

 2. Reference. Measurements in Electronics./ Ed. V.A. Kuznetsova. M. 1987.

 3. Kondryushin V.G. Determining the position of the vessel. M. Transport, 1984.

Claims (3)

 1. A radio navigation system consisting of a network of stations of repeaters with fixed parameters and receivers of calculators combined with moving objects, where each station contains a series-connected antenna unit, a first switch connected to a power amplifier by a second input, a matched radio receiver and an information parameters input unit, second an input connected to the first output of the synchronizer, the second output of which is through a series-connected block of parameters of service signals, the second switching a torus, the second input is connected to the third output of the synchronizer, and the coding unit is connected to the first input of the modulator, the second input of which is connected to the output of the stable frequency generator through the first discrete frequency divider, the output of the first discrete frequency divider is connected to the first input of the synchronizer, the fourth output of which connected counter and decoder connected to the second input of the synchronizer, the fifth output connected to the third input of the first switch, and the second input of the counter and the input of the synchronizer is connected to the output of the pulse counter generator, characterized in that a phase correction unit, a second discrete frequency divider, a phase discriminator are connected to the output of the stable frequency generator, the second input is connected to the output of the first switch through an active bandpass filter, and the key is output connected to the second input of the phase correction block, and the output of the second discrete frequency divider is simultaneously connected to the input of the pulse shaper counting and through The second switch, connected by the second and third inputs respectively to the modulator output and the sixth output of the synchronizer, is connected to the input of the power amplifier, while the output of the phase discriminator is connected through a series-connected analog-to-digital converter and the first register, the second input connected to the seventh output of the synchronizer, is connected to the third the input of the second switch, the fourth input of which through the driver of variable parameters, the second input connected to the eighth output of the synchronizer, is connected to the output the house of the input unit for inputting information parameters, at the same time the second key input and the third input of the first register are connected to the ninth output of the synchronizer, the fourth input of which is connected to the detector of service signals, the input connected to the output of the matched radio receiver, the output of which is through the comparison circuit, the second input is connected to the output of the second register connected to the fifth input of the synchronizer.  2. The system according to claim 1, characterized in that each receiver-calculator of the radio navigation system contains a series-connected antenna unit, a matched radio receiver, a block of constant storage registers, a second input connected to the first output of the synchronizer, a range calculator connected to the second input by a second input the output of the synchronizer, the coordinate calculator and the block fixing the coordinates, and the second output of the synchronizer is simultaneously connected to the second input of the coordinate calculator and to the first input of the optimizer Station ora, the second input of the range calculator connected to the output, and the first output of the station selection optimizer via the first block of registers connected to the third inputs of the coordinate calculator and range calculator, the fourth input of which is connected through the second block of registers and the counter of time intervals to the output of the stable frequency generator simultaneously connected to the first input of the synchronizer, and the output of the matched radio through the code comparison unit is connected to the second input with a synchronizer, the third output of which is connected to the second input of the second block of registers, while the second and third outputs of the optimizer of the station selection are respectively connected to the second input of the code comparison unit and the memory block of the station parameters, the second input connected to the fourth output of the synchronizer, and the output to the third input of the optimizer the choice of stations and the second input of the first block of registers, the active block filter and the phase discriminator are connected to the output of the antenna block in series, the second input is connected connected to the output of the discrete frequency divider, the output of which is connected through a series-connected reset pulse generator and logic circuitry to the second counter of time intervals and to the third input of the second block of registers, while the output of the matched radio receiver through the detector of service signals is connected to the third input of the synchronizer and through the third block of registers, the second input connected to the fifth output of the synchronizer, connected to the fifth input of the range calculator, and to the output fa A new discriminator is connected to a series-connected analog-to-digital converter and a fourth block of registers, the second input is connected to the sixth output of the synchronizer, and the output of the fourth block of registers is connected to the sixth input of the range calculator, simultaneously connected to the output of the phase discriminator are a series key and a phase correction unit, connected between the output of the stable frequency generator and the input of the discrete frequency divider, while the second inputs of the key and logic circuit And are connected to mym yield synchronizer eighth output of which is connected to the third input of the AND circuit, wherein the reset pulse generator output is connected to a fourth input of the synchronizer and via a series connection of a second counter, a second input connected to the ninth output of the synchronizer, and the decoder is connected to a fifth input of the synchronizer. 3. The system according to claim 2, characterized in that in it the range calculator is connected by an additional input to the output of the coordinate fixing unit, and the additional inputs of the coordinate and range calculators are connected to a voltage source proportional to the height H ₀ of the receiver-calculator antenna.

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