RU2697811C2 - Simulator of radio navigation signals - Google Patents

Abstract

FIELD: physics.SUBSTANCE: invention relates to radio navigation and can be used to generate radio signals similar to GLONASS and GPS global satellite radio navigation systems navigation satellites. Said result is achieved due to that simulator of navigation signals comprises digital signal generation unit, frequency converter up, attenuator, wherein said digital signal generation unit consists of an exchange interface unit, a pseudorandom sequence signal generation unit, a signal synthesis unit, a filter and an additional filter. Listed facilities included in the simulator are made and interconnected in a certain way.EFFECT: technical result is simple simulator and improved characteristics of output signal similar to real from satellite radio navigation systems GLONASS and GPS.1 cl, 2 dwg

Description

The invention relates to the field of radio navigation and can be used to generate radio signals similar to the GLONASS and GPS global navigation radio systems (SRNS) navigation from spacecraft (SC) with the corresponding state vector (spatial coordinates that make up the speed and time vector) for checking navigation receivers located on spacecraft located in geostationary, highly elliptical or arbitrary orbits, as well as signals of systems that functionally complement the SRNS.

A known method and device for checking devices that allow you to determine the location using auxiliary data, solves the problem of checking devices that allow you to determine the location using auxiliary data, which include the use of a simulator of the location object associated with the simulator of the base station, and the connection of the device under test, which allows to determine location using auxiliary data, to the base station simulator and to the glob simulator noy positioning system (RF patent №2328016).

The disadvantage of this device is the inability to generate high-precision signals (VT-code) GLONASS.

A well-known simulator based on the vector signal generator R&S SMBV100A with the SRNS software option provides signal modeling with motion profiles of the navigation receiver, multipath propagation of the navigation signal (NS), dynamic power control and atmospheric modeling, support for A-GPS, LTE, HSPA +, GSM / EDGE, HD radio ™ and FM stereo, with up to 12 GPS / Galileo real-time scenarios (www.rohde-schwarz.com/ad/smbv-gnss).

The disadvantage of this device is the inability to generate high-precision signals (VT-code) GLONASS.

Known imitator IM-2 JSC "MKB" Compass ", which generates GLONASS signals of standard accuracy (CT code) and high accuracy (VT code) in the frequency ranges L1 and L2, as well as GPS C / A (L1) with the speed of the object up to 8 km / s, acceleration up to 1000 m / s ² and a jerk up to 500 m / s ³ (Aerospace Review No. 4 of 2007).

The disadvantage of this device is the inability to form signals similar to the real navigation ones from the GLONASS and GPS ARNSs for spacecraft in geostationary or highly elliptical orbits, because they require high dynamic characteristics - for example, a simulated speed of up to 12 km / s.

This shortcoming was partially eliminated in the Spirent GSS8000 series satellite navigation system simulators, which have dynamic characteristics of a simulated speed of up to 120 km / s, acceleration up to 4450 m / s ² and a jerk up to 890000 m / s ³ at 3 frequencies with GPS support ( L1, L2 P (Y), L2C, L5, M-noise), SBAS (WAAS, EGNOS, MSAS), GLONASS (L1, L2) and Galileo (E1, E5a / b, E6, OS, CS, SOL).

The disadvantage of this device is the inability to generate high-precision signals (VT-code) GLONASS.

Generation of a radio frequency signal equivalent to the full combined navigation field of GLONASS (CT code (L1) and BT code (L2), as well as a rangefinder code in the frequency range L3), GPS, SBAS, Galileo provides SN-3803 (TDCC.464938.006) - a simulator signals of satellite navigation systems, ZAO KB NAVIS, capable of simulating complex dynamic movements of ground-based navigation receivers in any geographic area of the Earth with altitudes from minus 1 km to plus 8000 km with dynamic characteristics of a simulated speed of up to 12 km / s, acceleration up to 500 m / s ² and ry wkom up to 500 m / s ³ (registered in the State Register of measuring instruments No. 20278-00 of the Russian Federation; type approval certificate number: RU.C.33.018.B No. 8743 of January 27, 2000 GCI SI "Voentest"). Dimensions 420 × 500 × 157 mm, weight 16 kg.

The disadvantage of this device is the inability to form signals similar to the real navigation ones from the GLONASS and GPS ARNSs for spacecraft in geostationary or highly elliptical orbits.

A useful model is known for a simulator of navigation and inter-satellite radio signals (RF Patent No. 117644), including a power supply unit, a personal computer board unit, the input of which is the input of the device, a signal multiplier unit, the output of which is the output of the device, a single motherboard, and at least , one unit of the navigation module.

The disadvantages of this device is the presence of a personal computer board and a single motherboard, which complicates the design and requires special mathematical software that limits the ability to play navigation signals of an arbitrary grouping of spacecraft.

Closest to the claimed invention is a utility model of a simulator of navigation signals (RF Patent No. 123976), adopted as a prototype. The utility model includes a navigational signal shaper, which consists of a digital signal conditioning block and an up-converter, the output of which is connected in series with the attenuator and the transmitter antenna or the input of the navigation receiver. The digital signal generation unit has a digital information exchange interface node for directly inputting the navigation signal parameters, the outputs of which are connected to the inputs of the pseudorandom sequence signal generation unit and the inputs of the modulated signal synthesis unit; the outputs of the PSP signal generation unit are connected to the inputs of the modulated signal synthesis node, the outputs of which are connected to the input of the PSP signal generation unit, the input of the frequency converter up and the inputs of the adder, the output connected to the input of the filter, the output of which is connected to the input of the frequency converter up with heterodyne transfer frequency. In the signal synthesis node, for generating signals at the first intermediate frequency, taking into account the Doppler effect, direct digital synthesis is used based on the accumulating adder, with modulation at the second intermediate frequency.

The disadvantage of the prototype is the complexity of the implementation of the node for the synthesis of modulated signals, as well as the uneven group delay time (GW) of the generated signal, caused by the mandatory presence of a filter at the output of the frequency converter up, which is necessary to suppress the mirror channel that arose when the heterodyne frequency shift was up.

The aim of the present invention is to simplify the implementation of the modulated signal synthesis unit and to improve the output signal characteristics of radio signal generation devices, such as real navigation from the GLONASS and GPS satellite navigation systems.

This goal is achieved by the fact that in the block of the digital navigator of the navigation signal, from the simulator, containing a standard node for the interface of the exchange of digital information for directly entering the parameters of the navigation signal, the signal generation unit of the SRP, the signal synthesis node and the filter, an additional filter is added, and the signal synthesis node generates heterodyne signals F _{Г cos} and F _{Г sin} due to the introduced phase shifter. Also, due to the introduced phase shifters and digital synthesizers, the signal synthesis unit generates in-phase (I) and quadrature (Q) components for each signal from navigation spacecraft (NSC), which are separately modulated and summed into I- and Q-components of all channels. The inputs of the signal synthesis node are connected to the outputs of the digital information exchange interface node and the outputs of the SRP signal generation node, the outputs of the signal synthesis node are connected to the filter inputs. The outputs of the filters are the outputs of the sums of the I- and Q-components and the output of the digital signal conditioning unit. The digital block for generating the navigation signal has a standard digital interface for directly entering the parameters of the navigation signal from the corresponding control device, and the outputs of the block for digital forming of the navigation signal are the outputs of the I- and Q-components of the required navigation signal of the given constellation of the spacecraft at an intermediate frequency (IF) and heterodyne signals F _{Г cos} and F _{Г sin} for quadrature transfer of NS to a given frequency. The frequency converter up is implemented on the basis of the quadrature conversion principle, the in-phase and the quadrature component of the NS on the inverter are fed to the inputs, and the group of heterodyne signals F _{Г cos} and F _{Г sin} generated in the signal synthesis node is fed to other inputs. The output of the frequency converter upward is the output of the navigation signal of a given constellation of the spacecraft at the radiation frequency of a given SRNS. The attenuator output is the output of the navigation signal of the given constellation of the spacecraft at the radiation frequency of the given SRNS with the required radiation level for the transmitter antenna or the input of the navigation signal receiver.

The technical result provided by the given set of features, in addition to simplifying the device, is to improve the characteristics of navigation radio signals for arbitrary grouping of satellite and arbitrary trajectory and speed of the navigation receiver. These effects are achieved due to the structural construction of the simulator, in which the full cycle of the synthesis of I- and Q-components of the NS on the IF from one NKA can be implemented in a single chip (for example, AD9854ASQ). The received signal, presented in the form of I- and Q-components, is transferred to the HF region by the converter using the principle of quadrature conversion, which will allow us to abandon narrow-band output filters, thereby reducing the heterogeneity of the GWZ. These circumstances distinguish the claimed device from similar devices (imitators), where direct synthesis and heterodyne frequency transfer with the passage of a useful signal through a filter are used.

A simulator of navigation radio signals is illustrated in FIG. 1 and consists of a shaper of the navigation signal 1 with a digital interface at the input as part of the digital block 2, the frequency converter up 3 and the attenuator 4. The outputs of the digital block 2 are the output of the I- and Q-components of the real navigation signal of the given constellation of the spacecraft at an intermediate frequency and the output of the heterodyne signals required for quadrature transfer of the signal into the working RF region. The output of the frequency converter upward 3 is the output of the required navigation signal of a given NKA constellation at the radiation frequency of a given SRNS, which is connected through the attenuator 4 to the emitter antenna (or the input of the navigation signal receiver) 5. The digital signal conditioning unit 2 consists of an exchange interface node 6 connected with a node for generating signals PSP 7 and a node for synthesizing signals 8, also interconnected, and two filters 9.

The signal synthesis unit 8 is illustrated in FIG. 2, and consists of:

- reference generator 10 (in Fig. 2 is designated - exhaust gas);

- frequency synthesizer 11;

- frequency dividers 12 (in Fig. 2 are designated - D);

- phase shifters 13 (in Fig. 2 marked - 90 °);

- digital synthesizers 14 (in Fig. 2 are designated - ЦСn);

- modulators PSP 15 (in Fig. 2 are designated - Mn);

- digital-to-analog converters 16 (in Fig. 2 marked - DAC);

- adders 17 (in Fig. 2 marked - ∑ _I and ∑ _Q ),

where n is the number of synthesis channels of I- and Q-signals.

The device operates as follows. An array of digital information with the parameters of the navigation signal corresponding to the required type of satellite radio navigation system, the composition and nature of the movement of the satellite constellation, the nature of the movement of the navigation equipment of the consumer, etc., is transmitted to the navigation signal generator 1 via the standard digital interface. Further, by digital synthesis in the block digital formation of the navigation signal 2 is the formation of the navigation signal on the inverter with a normalized error in accordance with the received Settings. Next, the signals from the digital generation unit of the navigation signal 2 are fed to the input of the frequency converter up 3 for conversion into a navigation signal at a radiation frequency of a given SRNS. After the frequency converter up 3, the signal is attenuated by attenuator 4 to the levels of real signals from the satellite (or to any other desired level). After which the signal is emitted by the emitter 5, or fed through a high-frequency cable directly to the antenna input of the receiver of the navigation signal.

The digital formation block of the navigation signal 2 serves to generate I- and Q-components of the desired navigation signal at an intermediate frequency. Digital information with the required signal parameters is supplied from the external device to the exchange interface node 6, where it is converted into data for the PSP 7 signal generation unit and the frequency and phase parameters of the NSC signals for the signal synthesis unit 8. The intermediate signals created in the PSP 7 signal generation unit are modulated into the site of the synthesis of signals 8 carrier signals of I- and Q-components, rangefinding code. The carrier signals of the I- and Q-components are generated in accordance with the frequency and phase parameters coming from the exchange interface node 6. In the signal synthesis node 8, the synchronization signal FSS F _T and the local oscillator signals F _{Г cos} and F _{Г sin are} generated, which are necessary for transferring and converting I- and Q-components on the inverter to a navigation signal of the required frequency. Before the sum of the I- and Q-components arrives in the frequency converter up, the signals at the intermediate frequency pass through the filter 9, to highlight the useful signal.

The exchange interface node 6 and the signal processing unit PSP 7 can be performed similarly to the prototype.

The signal synthesis unit 8 has a frequency synthesizer 11, which, using the internal quartz OG 10 signal as a reference frequency, generates a local oscillator signal F _Г (aka F _Гcos ), from which a second reference signal F _{Гsin is obtained} , which is necessary for the quadrature frequency conversion. With divider D 12 of the local oscillator signal F _T is obtained clock frequency F _T for forming the CAP signals and the clock frequency F _T for CA 1 CA ... n 14. The frequency and phase of the signals in one channel for DS1 and TSS2 14 with phase difference of 90 ° obtained using the phase shifter 13, are set in such a way that the digital signals generated at the output of ЦС1 and ЦС2 14 correspond to the I- and Q-components of the generated signal from the RCA at the IF taking into account the Doppler frequency shift. Signals from DS1 and DS2 14 are fed to the inputs of the modulators M1 and M2 15, respectively. At the second inputs of the modulators M1 and M2 15, the signal PSP1 is supplied, and the output is a modulated digital signal. From the outputs of the modulators M1 and M2 15, the signal is fed to the corresponding DACs to convert the signal from digital to analog. Thus, the I- and Q-components of the navigation signal at the intermediate frequency are obtained, taking into account the Doppler shift modulated by the rangefinder code from the selected satellite.

A similar pairwise generation of the I- and Q-components of the signal from one NKA on the inverter occurs in all channels of signal formation in the signal synthesis node.

The generated I- and Q-components of the navigation signal from each channel are summed in the corresponding adders ∑ _I and ∑ _Q 17. The outputs of the adders ∑ _I and ∑ _Q 17 are the outputs of the signal synthesis unit.

Further, the sums of I- and Q-components (∑ _I and ∑ _Q ) for the entire group of navigation signals formed pass through the filters 9 and are fed to the input of the frequency converter up 3, the other inputs of which are supplied with reference signals (F _{Г cos} and F _{Г sin} ) , to convert the sum of I- and Q-components (∑ _I and ∑ _Q ) into a navigation signal at a radiation frequency of a given SRNS. After the frequency converter up 3, the signal is attenuated by attenuator 4 to the levels of real signals from the satellite (or to any other desired level). After which the signal is emitted by the emitter 5, or fed through a high-frequency cable directly to the antenna input of the receiver of the navigation signal.

The use of separate synthesis of I- and Q-components from one satellite makes it possible to use the quadrature conversion principle for up-converting frequencies, where the output does not require filters to suppress the mirror channel, which improves the simulation characteristics of the navigational signal shaper due to a more uniform GVZ. As a group of functional nodes required for the formation of one pair of I- and Q-components of the navigation signal (DS1 and DS2 14, M1 and M2 15, corresponding to DAC 16), you can use a quadrature synthesizer based on the principle of direct digital synthesis (for example, AD9854ASQ), which allows reduce overall dimensions and greatly simplify circuitry implementation. The separation of the general control circuit for generating signals into independent nodes of the digital information exchange interface, generating the baseband signal and synthesizing signals on the frequency converter, which was saved at the same time, allows us to abandon the built-in computer in the simulator and set the parameters of the required navigation signal in an external device, which significantly reduces the overall dimensions of the device (for example, in the form of a module in the "Euromechanics" construct) and simplifies its use as part of any test or navigation ion equipment for various purposes.

Due to a more uniform GVZ, the implementation of this technical solution allows you to create a device that has the best simulation characteristics. The use of unified microcircuits for the formation of modulated I and Q components of the NS on the inverter allows you to create a device with minimal hardware redundancy and small dimensions, which makes it easy to integrate it into third-party equipment providing the formation of a set of signals from the GLONASS and GPS satellite navigation systems corresponding to the state vector of the spacecraft moving along an arbitrary trajectory in the entire range of speeds, up to and including the second space velocity, including taking into account the influence of des the tabulating factors of outer space.

Claims (2)

1. A simulator of navigation radio signals of navigation spacecraft, comprising a navigation signal shaper, which consists of a digital signal conditioning unit (BCFS) and an up-converter, the output of which is connected to the input of the attenuator, the output of the attenuator is connected to the emitter or input of the navigation receiver, while the BTSC consists of from an exchange interface node, a pseudo-random sequence signal generation node (PSP), a signal synthesis node and a filter, while the input of the exchange interface node is is the input of the simulator, the first group of outputs of the node of the exchange interface is connected to the first group of inputs of the PSP signal generation unit, and the second group of outputs is connected to the first group of inputs of the signal synthesis unit, the second group of inputs of the signal synthesis unit is connected to the group of outputs of the PSP signal generation unit, and signal synthesis consists of a reference generator, a frequency synthesizer, a frequency divider, digital synthesizers (DS), modulators, and the output of the frequency divider of the signal synthesis node, which is the output of the signal synchronization and clock frequency, respectively connected to the synchronization input of the PSP signal generation unit and to the second inputs of the DS, the first group of inputs of which is the first group of inputs of the signal synthesis node, the second group of inputs of the signal synthesis node is modulator inputs, characterized in that the signal synthesis node the first phase shifter, second phase shifters, as well as additional digital synthesizers, additional modulators, digital-to-analog converters (DACs), adders, and in the BCFS introduced an additional filter, while the signal synthesis unit forms the in-phase and quadrature components of the navigation signal at an intermediate frequency (IF), the input of the first phase shifter is connected to the output of the frequency synthesizer, and the output of the first phase shifter is the output of the signal synthesis unit, forming a group of output heterodyne signals with the frequency synthesizer signal F _F F _{F cos} and _sin BTSFS output unit arriving at the frequency up converter to the input of the second phase shifter is fed one of the signals of the first group of inputs the signal synthesis unit , the outputs of the second phase shifters are connected to the introduced additional digital synthesizers, forming the quadrature component of the navigation signal (NS) on the inverter, the second inputs of the additional DS receive the clock signals from the output of the frequency divider, the outputs of the DS are connected to the first inputs of the corresponding modulators, the second inputs of the modulators are the second a group of inputs of the signal synthesis node, the outputs of the modulators are connected to the inputs of the DAC, the outputs of the DAC converting in-phase and quadrature components of the signals on the IF, with are dined with the inputs of the respective adders, the outputs of the adders are the outputs of the in-phase and quadrature component of the NS to the inverter of the signal synthesis unit, the in-phase output is connected to the input of the filter, the quadrature output is connected to the input of an additional filter, the outputs of the filters are the outputs of the BCFS in-phase and quadrature components of the NS to the inverter, connected to the inputs of the frequency converter up; 2. The device according to p. 1, characterized in that the up-converter is implemented on the basis of the quadrature conversion, having at the input a heterodyne group of signals F _{Г cos} and F _{Г sin} connected to a heterodyne group of outputs of the BCFS, the first input of the frequency converter up is an in-phase input a component of the NS connected to the output of the in-phase component of the BCFS, the second input is the input of the quadrature component of the NS connected to the output of the quadrature component of the BCFS.

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