RU2159448C1 - Device for receiving signals from satellite radio navigation systems - Google Patents

Abstract

FIELD: radio navigation systems. SUBSTANCE: device designed for operation in satellite radio navigation systems in response to GPS and GLONASS signals in frequency range L1 with C/A code modulation and at GLONASS warrant frequencies i = -7 - 4 and i = 0 - 12 has input unit incorporating at least one band filter, first signal frequency conversion unit incorporating at least one mixer, channels of second frequency conversion unit for GPS and GLONASS signals, respectively, each incorporating filter, mixer, and analog-to-digital conversion unit built around amplifier and threshold elements. Device also has clock and heterodyne- frequency signal shaping equipment whose clock signal shaping unit made in the form of scale-of-eight division unit is connected to output of third heterodyne-frequency signal shaping unit which is, essentially, scale-of-eight division unit connected to output of first heterodyne-frequency signal shaping unit. The latter and second heterodyne-frequency signal shaping unit are, essentially, variable frequency synthesizers whose reference inputs are connected to output of frequency standard and control inputs function as device control inputs. EFFECT: simplified mechanical design. 3 cl, 5 dwg

Description

 The invention relates to radio navigation and can be used in the navigation equipment of consumers of satellite radio navigation systems (CPHC), and in particular, in radio receivers that simultaneously receive CPHC GLONASS and GPS signals in the frequency range L1 with code modulation C / A code - code "standard accuracy" .

 Consumer navigation equipment CPHC GLONASS (Global Navigation Satellite System) [1] and GPS (Global Positioning System) [2] are currently widely used to determine the coordinates (latitude, longitude, altitude) and speed of objects, as well as time. In this case, the use of CPHC signals of the frequency range L1 with code modulation with C / A code - a code of "standard accuracy" - provides "standard" accuracy of determination.

 The main differences between CPHC GPS and GLONASS are the use of different, albeit adjacent, frequency ranges, the use of different pseudo-noise modulating codes, and the use of code and frequency separation of the signals of different satellites in the system, respectively. So, in CPHC GPS in the frequency range L1, satellites emit signals modulated by various pseudo-noise codes on one carrier frequency 1575.42 MHz, and CPHC GLONASS satellites emit signals modulated by the same pseudo-noise code on different carriers (letter) frequencies lying in the adjacent frequency area.

The nominal frequencies in the CPHC GLONASS are formed according to the rule
f _i = f ₀ + iΔf,
where f ₁ - denominations of letter frequencies;
f ₀ - zero lettering frequency;
i - numbers of letter frequencies;
Δf is the interval between letter frequencies.

For the frequencies of the considered range L1: f ₀ = 1602 MHz, Δf = 0.5625 MHz.

 The distribution of letter frequencies among functioning CPHC GLONASS satellites is set by the almanac transmitted in the overhead information frame.

 The letter frequencies of the CHPC GLONASS signals are entered in accordance with the “Interface Control Document” [1]. At present (since 1998) the letter frequencies of the range from i = 0 to i = 12 have been introduced; later, in accordance with [1], a transition to the letter frequency range from i = -7 to i = 4 is provided. GLONASS CPHC signals to another frequency domain is associated with the allocation of new frequencies for the operation of communication systems. In this regard, the problem arises of making the equipment capable of receiving CPHC GLONASS signals available, both under the conditions of the indicated change in the letter frequency range, and in conditions of increasing complexity of the noise situation due to the operation of communication systems in a close frequency range.

 The differences noted above between the signals of the CPHC GPS and GLONASS satellites resulting from the code separation at one carrier in the CPHC GPS and the frequency separation at several carriers determined by the letter frequencies in the CPHC GLONASS determine the differences in the technical means by which the signals of these systems to a form allowing subsequent radio navigation measurements.

 It is known, for example, from [3, FIG. 1], a device for receiving CPHC GPS signals, comprising a low-noise amplifier, a filter, a first mixer, a first intermediate frequency amplifier, a quadrature mixer, two quantizers for in-phase and quadrature channels, a signal generator of the first heterodyne frequency (1401.51 MHz), and also a unit division, forming from the signal of the first heterodyne frequency signal of the second heterodyne frequency.

 The device solves the technical problem of receiving and converting CPHC GPS signals to a form that allows the consumer to carry out further appropriate radio navigation measurements. The device does not allow to solve the problem of receiving CPHC GLONASS signals.

 It is known, for example, from [4, p. 147-148], a device for receiving CPHC GLONASS signals ("single-channel consumer equipment" ASN-37 "). The device contains an input filter, a low-noise amplifier, a first mixer, an intermediate frequency amplifier, a phase demodulator, a second mixer with phase suppression of the mirror channel, a limiter , letter frequency synthesizer, heterodyne frequency generators. Letter frequency synthesizer generates its output signals in accordance with the letter frequencies of the received signals GLONASS CPHC. Step of letter frequencies generated by the synthesizer Is 0.125 MHz signal of the first heterodyne frequency is formed by multiplying the output signal into four frequency synthesizer, and the signal of the second heterodyne frequency -. By dividing the output signal of the frequency synthesizer by two.

 The device solves the technical problem of receiving and converting CPHC GLONASS signals to a form that allows the consumer to carry out appropriate radio navigation measurements. The device does not solve the problem of receiving CPHC GPS signals.

 Despite the differences that exist between CPHC GPS and GLONASS, their proximity to the ballistic construction of the orbital constellation of navigation satellites and the used frequency range allows us to pose and solve problems associated with the creation of integrated navigation equipment for consumers working on the signals of these two systems. The result achieved in this case is to increase the reliability, reliability and accuracy of determining the location of an object, in particular, due to the possibility of choosing the working constellations of navigation satellites with the best values of geometric factors [2, p. 160]. All this determines the relevance of the task of developing integrated receiving devices operating on the signals of both systems, and optimizing technical solutions aimed at simplifying and minimizing these devices.

 Among such integrated receiving devices it is known, see, for example, [4, p. 158-161, Fig. 9.8], a device that solves the problem of receiving CPHC GPS and GLONASS signals of the L1 frequency range and converting them to a form that allows using the digital processor (primary processing processor and navigation processor) to carry out subsequent radio navigation measurements and determining the location of the object. The device contains a frequency splitter (“diplexer”), performing frequency separation of the CPHC GPS and GLONASS signals, bandpass filters and low-noise amplifiers of GPS and GLONASS channels, a mixer, a microwave switch that connects CPHC GPS or GLONASS signals to the mixer input, and a microwave switch that connects to the mixer reference input is the signal of the first local oscillator for the GPS channel or the GLONASS channel. In this device, due to the corresponding generation of the heterodyne signal frequency, the first intermediate frequency is constant for the CPHC GPS and GLONASS signals and the entire further path of the device is implemented as common for these signals.

 A feature of the device is that the reception and conversion of signals of each of the systems is carried out sequentially in time using the same radio path, which increases the time spent on obtaining navigation information.

 A device for receiving signals CPHC GPS and GLONASS, described in [5, p. 835-844, FIG. 2], which solves the problem of simultaneously receiving CPHC GPS and GLONASS signals. The functionally complete part of this device, which solves the problem of receiving CPHC GPS and GLONASS signals in the frequency range L1 and generating output signals used in subsequent radio navigation measurements, is adopted as a prototype.

 A block diagram of a device for receiving CPHC signals adopted as a prototype is shown in FIG. 1.

 The device adopted as a prototype contains (Fig. 1) an input unit 1, the input of which is the signal input of the device, unit 2 of the first signal frequency conversion, first 3 and second 4 channels of the second signal frequency conversion, respectively, CPHC GPS and GLONASS, as well as equipment 5 generation of clock and local oscillation signals, containing a separate clock signal generation unit - a clock signal generator and three separate heterodyne frequency signal generation units - three frequency synthesizers (on Fig. 1 is not shown).

 The input unit 1 solves the problem of pre-filtering the input signals CPHC GPS and GLONASS and includes at least one band-pass filter (not shown in Fig. 1).

 Block 2 solves the problem of the first frequency conversion of CPHC GPS and GLONASS signals and includes at least one mixer (not shown in Fig. 1).

 Channel 3 of the second signal frequency conversion (channel of the second frequency conversion of CPHC GPS signals) contains a filter 6 connected in series, mixer 7 and an analog-to-digital conversion unit 8, the output of which forms the channel output — the output of the converted CPHC GPS signals.

 Channel 4 of the second signal frequency conversion (channel of the second signal conversion of the CPHC GLONASS signals) contains a series-connected filter 9, mixer 10 and an analog-to-digital conversion unit 11, the output of which forms the channel output — the output of the converted GLONASS CPHC signals.

 The inputs of the filters 6 and 9, which are inputs of the first 3 and second 4 channels of the second signal frequency conversion, respectively, are connected to the output of block 2 of the first signal frequency conversion. The input of block 2 is connected to the output of block 1. The reference input of the mixer (not shown in FIG. 1) of block 2 of the first signal frequency conversion, forming the reference input of block 2, is connected to the signal output of the first heterodyne frequency of the equipment 5, formed by the output of the signal generation block of the first heterodyne frequency (not shown in figure 1). The reference inputs of the mixers 7 and 10 of the first 3 and second 4 channels of the second signal frequency conversion are connected respectively to the outputs of the signals of the second and third heterodyne frequencies of the equipment 5, formed by the outputs of the corresponding signal generation blocks of the second and third heterodyne frequencies (not shown in Fig. 1).

 The outputs of the channels 3, 4 of the second signal frequency conversion and the output of the clock signal of the equipment 5, formed by the output of the clock signal generating unit (not shown in Fig. 1), are the outputs of the prototype device.

 The prototype device operates as follows.

 The CPHC GPS and GLONASS signals of the frequency range L1 from the input antenna (not shown in FIG. 1) through the input unit 1, which carries out the frequency filtering of the signals of this frequency range, are fed to the input of the unit 2 of the first signal frequency conversion. In block 2, the CPHC GPS and GLONASS signals of the frequency range L1 are converted in frequency using a mixer, which is part of block 2.

For the first frequency conversion, carried out in block 2, the prototype device uses the signal of the first heterodyne frequency f _r1 = 1416 MHz coming from the corresponding output of equipment 5. In equipment 5, the signal of the first heterodyne frequency f _{r1 is} synthesized using a separate signal conditioning unit of the first heterodyne frequency - the first frequency synthesizer (not shown in FIG. 1).

 The CPHC GPS and GLONASS signals of the frequency range L1 converted in block 2 are fed to the inputs of the first 3 and second 4 channels of the second signal frequency conversion, that is, to the inputs of filters 6 and 9. Each of these filters filters the signals of one of the systems, namely, a filter 6 - filtering CPHC GPS signals, and filter 9 - filtering CPHC GLONASS signals.

 Filtered using filters 6 and 9 from out-of-band interference and separated by systems (GPS and GLONASS), the signals in each of channels 3 and 4 are fed to the signal inputs of mixers 7 and 10, respectively.

For the second frequency conversion carried out in channels 3 and 4, the prototype device uses the signals of the second and third heterodyne frequencies f _r2 = 173.9 MHz and f _r3 = 178.8 MHz, synthesized using the corresponding separate signal generation blocks of the second and third heterodyne frequencies - the second and third frequency synthesizers (not shown in Fig. 1), which are part of the equipment 5. The signal of the second heterodyne frequency f _r2 = 173.9 MHz is used to convert CPHC GPS signals in mixer 7 of the first channel 3, and third hetero signal constant frequency f _r3 = 178,8 MHz is used for conversion CPHC GLONASS signals in the mixer 10 of the second channel 4.

The CPHC GPS and GLONASS signals converted using mixers 7 and 10 are then fed to the inputs of blocks 8 and 11 of the analog-to-digital conversion, where they are converted to digital form. The conversion to digital form is carried out in the prototype device with a clock frequency F _T , determined by the clock frequency signal generated in the apparatus 5 (in Fig. 1, the connection of blocks 8, 11 with the apparatus 5 is not shown).

 The CPHC GPS and GLONASS signals converted into digital form in channels 3 and 4, and the clock signal generated in the apparatus 5 using a separate clock signal generating unit, for example, using a crystal oscillator (not shown in FIG. 1), the output signals of the prototype device.

 The output signals of the device are used to perform subsequent radio navigation measurements and obtain navigation information. When performing radio navigation measurements, CPHC signals are digitally correlated. The clock signal generated in the device is used as a signal from which clock signals are generated for digital correlation processing.

For digital processing without loss of navigation information, the output signals of the prototype device are consistent in frequency and spectrum. Coordination is ensured by selecting certain values of the clock and heterodyne frequencies. So, in the prototype device, the value of the clock frequency that determines the frequency of the analog-to-digital conversion, that is, the sampling frequency in time, is selected f _T = 57.0 MHz. With this frequency in mind, the harmonized heterodyne frequencies f _r2 = 173.9 MHz and f _r3 = 178.8 MHz were chosen for the second signal frequency conversion, namely, in such a way that the average frequency of the GLONASS and GPS CPHC signals at the second intermediate frequency would be close to 14.25 MHz. This provides the ability to digitally convert signals in blocks 8, 11 using 4-bit analog-to-digital converters with a clock frequency f _T = 57.0 MHz (4 x 14.25 MHz), and also makes it possible to use specialized digital processing filters that select two-bit in-phase and quadrature samples with a frequency of 28.5 MHz (2 x 14.25 MHz) [5, p. 837].

 Thus, in the prototype device, the following clock and local oscillation frequency signals are generated: clock - 57.0 MHz, first heterodyne - 1416 MHz, second heterodyne - 173.9 MHz, third heterodyne - 178.8 MHz.

The formation of these clock and local oscillation frequency signals is carried out in the prototype device using equipment 5, the complexity of which is due to the fact that neither the clock nor any of the local oscillation frequencies can be obtained from another heterodyne frequency used in the prototype device, by a simple multiplication or division. Therefore, the heterodyne frequencies are formed (synthesized) in apparatus 5 using three separate generators (synthesizers) of the heterodyne frequencies, and the clock frequency using a separate clock generator. Each of the drivers (synthesizers) of heterodyne frequencies is an independent radio engineering device, the complexity of its implementation is due to the high requirements for the stability of the synthesized frequencies (relative frequency instability 10 ^-11 -10 ^-12 for 1 s [6]), since The output characteristics of the receiving device as a whole depend on the degree. Such a solution - the use of three separate heterodyne frequency synthesizers and a separate clock generator in the equipment for generating clock and local oscillation frequencies, as well as the high value of the generated clock frequency (57.0 MHz), which complicates the equipment used in subsequent digital signal processing, makes it difficult use of the prototype device as a receiver for portable (portable, handheld) transceivers that determine the location of an object using CPHC GPS and GLONASS signals.

A feature of the prototype device is also that the solutions implemented in it when receiving and processing received signals are based on the use of CPHC GLONASS signals of a certain range of letter frequencies (with letter numbers from i = 0 to i = 24) and the corresponding clock value in this range frequency F _T = 57 MHz. However, the prototype device does not provide technical means for receiving CPHC GLONASS signals with letter numbers in the range from i = -7 to i = -1, introduced in accordance with [1]. A possible solution to the problem of receiving CPHC GLONASS signals with letter frequencies, including the indicated additional letter frequencies, within the framework of the prototype device structure can be achieved by expanding (by about 30%) the radio frequency path bandwidth for CPHC GLONASS signals and a corresponding increase in clock frequency. In this case, however, there are problems with ensuring noise immunity, and an increase in the clock frequency leads to an increase in the power consumed during digital processing.

 In this regard, the urgency of the task of simplifying equipment performing the generation of clock and local oscillation frequency signals in the receiver, for example, reducing the number of heterodyne frequency synthesizers and decreasing the clock frequency, is obvious. It is also relevant to ensure that the receiving device can operate under the conditions of the indicated change in the letter frequency range of the CPHC GLONASS signals from the consumer without its constructive development. The possibility of creating serial small-sized (portable, pocket-sized) receiver indicators that determine the location of an object using CPHC GLONASS and GPS signals, including receiver indicators whose life cycle falls within the period of change in accordance with [1] the range of letter frequencies of CPHC GLONASS signals, depends on the solution of these problems. .

 The objective of the invention is the creation of a device that simultaneously receives and converts CPHC GLONASS and GPS signals of the L1 frequency range, with equipment that is simpler than the prototype for generating clock and local oscillation frequencies, with the possibility of receiving and processing CPHC GLONASS signals under the conditions entered in accordance with [1] new ranges of letter frequencies of signals (i = 0-12 and i = -7-4). The bandwidth of the radio frequency path, which determines the noise immunity of the receiving device, is narrowed as much as possible, and the clock frequency, consistent with the spectrum of the received signals, is reduced in comparison with the prototype. It is taken into account that the spectra of the processed CPHC GPS and GLONASS signals include four side lobes on either side of the carrier to enable the subsequent digital processing to implement the so-called “narrow correlator”, which improves the processing of CPHC signals in the presence of interfering signals [7,8, nine].

 The essence of the invention lies in the fact that in a device for receiving signals from satellite radio navigation systems containing an input unit comprising at least one band-pass filter connected to the output of the input unit, a first signal frequency conversion unit comprising at least one mixer connected to the output of the first signal frequency conversion unit, the first and second channels of the second signal frequency conversion, respectively, CPHC GPS and GLONASS, each of which contains series-connected phi a liter, the input of which is the input of the channel, a mixer and an analog-to-digital conversion unit, the output of which is the output of the channel, as well as equipment for generating clock and heterodyne signals, containing a signal generating unit of the first heterodyne frequency, a signal generating unit of the second heterodyne frequency, and a signal generating unit the third heterodyne frequency and the clock signal generating unit, and the output of the first heterodyne frequency signal of the clock and heterodyne signal generation equipment the frequency generated by the output of the signal conditioning unit of the first heterodyne frequency is connected to the reference input of the mixer of the first signal frequency conversion unit, the output of the second heterodyne frequency signal formed by the output of the signal conditioning unit of the second heterodyne frequency is connected to the reference input of the mixer of the first channel of the second signal frequency conversion, and the output signal of the third heterodyne frequency, formed by the output of the signal generation unit of the third heterodyne frequency, is connected to the reference input with the mixer of the second channel of the second signal frequency conversion, while the outputs of the first and second channels of the second signal frequency conversion and the output of the clock frequency signal of the clock and heterodyne signal generating equipment, formed by the output of the clock signal generating unit, are the device outputs, and the input unit input is the signal the input of the device, in the channels of the second signal frequency conversion, each of the blocks of the analog-to-digital conversion is made in the form of series-connected of the amplifying element and the threshold element, in the equipment for generating clock and local oscillation frequency signals, the clock signal generating unit is made in the form of a frequency division unit by eight, and the input of the clock signal generating unit is connected to the output of the third heterodyne signal generating unit made in the form of a block dividing the frequency by eight, the input of the signal conditioning unit of the third heterodyne frequency is connected to the output of the signal conditioning unit of the first heterodyne frequency, while signal generating unit of the first heterodyne frequency block and a signal of the second heterodyne frequency formed in a tunable frequency synthesizer, the reference inputs are connected to the reference generator output, and control inputs constitute the control inputs of the device.

 In particular cases of the implementation of the claimed device, the amplifying and threshold elements of the blocks of analog-to-digital conversion of the channels of the second signal frequency conversion can be performed, for example, in the form of an amplifier with automatic gain control and a two-bit quantizer in level, as well as in the form of an amplifier with a constant gain and binary quantizer by level.

The essence of the claimed invention, the possibility of its implementation and industrial use are illustrated by the drawings and frequency diagrams presented in FIG. 1 -5, where:
in FIG. 1 shows a structural diagram of a device adopted as a prototype;
in FIG. 2 presents a structural diagram of the inventive device in one of the possible options for its implementation;
in FIG. Figure 3 presents frequency diagrams explaining the distribution of the frequency bands of GPS CPHC signals (Fig. 3a) and GLONASS CPHC signals with the letter frequencies of the first range i = 0-12 (Fig. 3b) and the second range i = -7-4 (Fig. 3c) ) before the first frequency conversion;
in FIG. 4 are frequency diagrams explaining the distribution of the frequency bands of the CPHC GPS (Fig. 4a, b) and GLONASS (Fig. 4c, d) signals in the inventive device after the first signal frequency conversion for the first (Fig. 4a, c) and second (Fig. 4b, d) operating modes corresponding to the reception of CPHC GLONASS signals of the first and second letter frequency ranges with letter numbers i = 0-12 and i = -7-4, respectively;
in FIG. 5 is a frequency diagram explaining the distribution of the frequency bands of the CPHC GPS signals (Fig. 5a, b) and GLONASS (Fig. 5c, d) in the inventive device after the second frequency conversion for the first (Fig. 5a, c) and second (Fig. 5b , d) operating modes corresponding to the reception of CPHC GLONASS signals of the first and second letter frequency ranges with letter numbers i = 0-12 and i = -7-4, respectively.

 The inventive device for receiving signals from satellite navigation systems in this example implementation contains (see Fig. 2) an input unit 1, the input of which is the signal input of the device, unit 2 of the first signal frequency conversion, the first 3 and second 4 channels of the second signal frequency conversion, respectively, CPHC GPS and GLONASS, as well as equipment 5 for generating clock and heterodyne signals.

 Channel 3 of the second signal frequency conversion (channel of the second frequency conversion of CPHC GPS signals) contains a filter 6 connected in series, mixer 7 and an analog-to-digital conversion unit 8, the output of which forms the channel output — the output of the converted CPHC GPS signals.

 Channel 4 of the second signal frequency conversion (channel of the second signal conversion of the CPHC GLONASS signals) contains a series-connected filter 9, mixer 10 and an analog-to-digital conversion unit 11, the output of which forms the channel output — the output of the converted GLONASS CPHC signals.

 In channel 3, the analog-to-digital conversion unit 8 is made in the form of series-connected amplifier element 12 and threshold element 13.

 In channel 4, the analog-to-digital conversion unit 11 is made in the form of series-connected amplifier element 14 and threshold element 15.

 The clock and heterodyne frequency signal generating apparatus 5 comprises a first heterodyne frequency signal generating unit 16, a second heterodyne frequency signal generating unit 17, a third heterodyne frequency signal generating unit 18, a clock signal generating unit 19 and a reference oscillator 20.

The output signal of the clock frequency of the equipment 5 (F _T ), formed by the output of the block 19 of the formation of the clock signal, and the outputs of the first 3 (GPS) and second 4 (GLONASS) channels of the second signal frequency conversion are the outputs of the device.

 In the apparatus 5, the clock signal generating unit 19 is made in the form of a unit for dividing the frequency by eight. The input of the clock signal generating unit 19 is connected to the output of the third heterodyne frequency signal generating unit 18. The signal generating unit 18 of the third heterodyne frequency is made in the form of a unit for dividing the frequency by eight. The input of the signal generating unit 18 of the third heterodyne frequency is connected to the output of the signal generating unit 16 of the first heterodyne frequency. The signal generating unit 16 of the first heterodyne frequency and the signal generating unit 17 of the second heterodyne frequency are made in the form of tunable frequency synthesizers. The reference inputs of the blocks 16 and 17 (reference inputs of the frequency synthesizers) are connected to the output of the reference generator 20. The control inputs of the blocks 16 and 17 (the control inputs of the frequency synthesizers) form the control inputs of the device (UPR), to which control signals are supplied, for example, from the navigation processor (not shown in Fig. 2) to establish the operating modes of the device corresponding to the reception of CPHC GLONASS signals of the first or second letter frequency ranges with letter numbers i = 0-12 or i = -7-4, respectively.

 The input unit 1, which solves the problem of pre-filtering the input signals CPHC GPS and GLONASS, contains at least one band-pass filter. In this example implementation (Fig. 2), which has practical application, the input unit 1 contains a series-connected first band-pass filter 21, an amplifier 22 and a second band-pass filter 23.

 To the input of block 1, that is, to the input of the filter 21, a receiving antenna is connected.

 Block 2, which solves the problem of the first frequency conversion of CPHC GPS and GLONASS signals, contains at least one mixer. In the considered example of implementation (Fig. 2), having practical application, block 2 contains series-connected first amplifier 24, mixer 25 and second amplifier 26.

 The inputs of the filters 6 and 9, which are inputs of the first 3 and second 4 channels of the second signal frequency conversion, respectively, are connected to the output of block 2 of the first signal frequency conversion, that is, to the output of amplifier 26. The input of block 2, that is, the input of amplifier 24, is connected to the output input unit 1, that is, to the output of the bandpass filter 23.

 The signal output of the first heterodyne frequency of the equipment 5, that is, the output of block 16, is connected to the reference input of the mixer 25 of block 2 of the first signal frequency conversion. The signal output of the second heterodyne frequency of the equipment 5, that is, the output of block 17, is connected to the reference input of the mixer 7 of channel 3 of the second signal frequency conversion. The signal output of the third heterodyne frequency of the equipment 5, that is, the output of block 18, is connected to the reference input of the mixer 10 of channel 4 of the second signal frequency conversion.

 Components of the claimed device elements, nodes and blocks are known elements, nodes and blocks, practically used in the technique of receiving CPHC signals.

 So, the input unit 1, including the bandpass filters 21, 23 and the amplifier 22, can be implemented, for example, using standard ceramic filters that implement the functions of the bandpass filters, and an amplifier type MGA-87563 from HEWLETT-PACKARD.

 Amplifier 24, mixer 25 and amplifier 26, which are part of unit 2 of the first signal frequency conversion, can be implemented, for example, using a NEC type UPC2731 chip.

 Filters 6, 9, which are part of channels 3 and 4 of the second signal frequency conversion, can be implemented as band-pass filters on surface-acoustic waves (SAWs), see, for example, [10, p. 217-220]; mixers 7, 12 and amplifying elements 12, 14 (including the version with adjustable gain) can be implemented, for example, using NEC type UPC2753 microchips, and threshold elements 13.15 using ANALOG DEVICES comparators type AD9696 .

 The components of the apparatus 5 blocks 16, 17, 18, 19 and the reference generator 20 are implemented on elements manufactured by the industry.

 So, the reference oscillator 20, which is part of the apparatus 5, can be implemented as a quartz oscillator that generates a signal with a frequency, for example, 10 MHz. In particular, a thermocompensated quartz oscillator of the TEMPUS-LVA type by MOTOROLA can be used.

 Blocks 16 and 17 of the formation of signals of the first and third heterodyne frequencies (tunable frequency synthesizers) are standard devices described, in particular, in [11, p. 158-169, FIG. 6]. The circuit of a standard frequency synthesizer consists of a series-connected phase-locked loop (PLL), a filter (for example, a low-pass filter - low-pass filter) and a voltage controlled oscillator (VCO). The VCO output forms the output of the frequency synthesizer. The output of the VCO is connected to the signal input of the PLL, the reference and control inputs of which form the reference and control inputs of the frequency synthesizer. As a VCO in such a synthesizer, for example, a generator can be used, which is part of the above NEC UPC2731 chip. The PLL block of the synthesizer can be implemented, for example, using a chip type SP8853 from GEC Plessey Semiconductors, which contains tunable frequency dividers (for synthesized and reference signals), a phase detector, and registers for recording data that establish certain division factors of frequency dividers. The division coefficients of the PLL block frequency dividers are set by external signals - digital codes supplied to the control inputs of the indicated microcircuit via the serial interface from the control input (control) of the device. The division factors of the PLL frequency dividers are set based on the required ratio between the reference frequency generated by the reference oscillator 20 and the frequency of the output VCO signal, depending on the operating mode of the device, determined by the letter frequency range of the GLONASS CPHC signals (i = 0-12 or i = -7 -4). The phase PLL detector in such a synthesizer generates a voltage corresponding to the mismatch of the phases of the reference and generated signals arriving at the inputs of the phase detector from the outputs of the respective frequency dividers. The output voltage of the phase detector is converted using a filter, after which it is supplied to the VCO varicap, adjusting the generated frequency accordingly and thereby closing the feedback circuit.

 The third heterodyne frequency signal generating unit 18 and the clock signal generating unit 19, which are eight frequency dividers, can be implemented, for example, on G8 Plessey Semiconductors type eight frequency divider ICs (SP8808).

 The operation of the claimed device for receiving signals from satellite navigation systems will consider the example of the reception and processing of signals CPHC GPS and GLONASS frequency band L1 with code modulation C / A code (code "standard accuracy") for two modes corresponding to two letter frequency ranges of CPHC GLONASS signals letter numbers respectively i = 0-12 and i = -7-4.

 The inventive device for receiving signals from satellite navigation systems works as follows.

 The CPHC GPS and GLONASS signals of the frequency range L1 received by the antenna are fed to the signal input of the device, that is, to the input of input unit 1 (Fig. 2). CPHC GPS signals of the L1 band occupy frequency bands with a width of ΔF = 8.184 MHz (four lobes in the signal spectrum on both sides of the carrier for the implementation of a “narrow correlator”). CPHC GLONASS signals of the L1 band occupy frequency bands (four lobes in the signal spectrum on both sides of the carrier for the implementation of a “narrow correlator”) of width ΔF = 10.838 MHz (case of letter frequencies i = 0-12) and ΔF = 10.2755 MHz ( case of letter frequencies i = -7-4). The position of the frequency bands occupied on the frequency axis by the CPHC GPS and GLONASS signals of the L1 range is shown in FIG. 3, where FIG. 3a is a frequency band of CPHC GPS signals (1571.328 - 1579.512) MHz, FIG. 3b is a frequency band of CPHC GLONASS signals for the case of letter frequencies i = 0-12 (1599.956 - 1610.794) MHz, FIG. 3c - frequency band of CPHC GLONASS signals for the case of letter frequencies i = -7-4 (1596.019 - 1606.294) MHz. The input unit 11 passes the CPHC GPS and GLONASS signals to its output in the entire range of the indicated frequency bands (i.e., frequencies from 1571.328 to 1610.794 MHz).

 In the input unit 1, the signals CPHC GPS and GLONASS of the frequency range L1 are fed to the input of the first band-pass filter 21, which carries out frequency filtering of the signals of this frequency range. From the output of the filter 21, the CPHC GPS and GLONASS signals are fed through an amplifier 22 to the input of the filter 23, which in this case is made similar to the filter 21 and has the same amplitude-frequency characteristic. The use of two band-pass filters 21 and 23, connected by an amplifier 22, makes it possible to simplify the implementation of the necessary characteristics of the input unit 1 in terms of frequency selectivity and signal-to-noise ratio for a specified total bandwidth (1571.328 - 1610.794) MHz.

 From the output of block 1, the CPHC GPS and GLONASS signals of the frequency range L1 are fed to the input of block 2 of the first signal frequency conversion, where they are amplified in the first amplifier 24, converted in frequency in the mixer 25, and amplified in the second amplifier 26 (first intermediate frequency amplifier).

For the first frequency conversion, carried out in the mixer 25 of block 2, the signal of the first heterodyne frequency is used, which is synthesized in block 16 from the 10 MHz reference signal generated by the reference generator 20. In the first mode of operation of the inventive device, the signal frequency of the first heterodyne frequency is set f _r1 (1 ) = 1412 MHz, and in the second, f _r1 (2) = 1408 MHz.

 As a result of the first frequency conversion, the position of the frequency bands occupied by the CPHC GPS and GLONASS signals on the frequency axis changes as shown in FIG. 4, where FIG. 4a is the location of the frequency bands of the CPHC GPS signals for the first mode of operation (159.328 - 167.512) MHz, FIG. 4b is the location of the frequency bands of the CPHC GPS signals for the second mode of operation (163.328 - 171.512) MHz, FIG. 4c shows the arrangement of frequency bands of CPHC GLONASS signals for the first mode of operation (187.956 - 198.794) MHz, FIG. 4d - arrangement of frequency bands of CPHC GLONASS signals for the second mode of operation (188.019 - 198.294) MHz.

 The signals CPHC GPS and GLONASS, converted to the first intermediate frequency in block 2, are output from the amplifier 26 to the inputs of the first 3 and second 4 channels of the second signal frequency conversion, that is, to the inputs of filters 6 and 9. Each of these filters carries out band-pass filtering of signals of the corresponding CPHC namely, filter 6 - filtering CPHC GPS signals in the frequency range (159.328 - 171.512) MHz, and filter 9 - filtering CPHC GLONASS signals in the frequency range (187.956 - 198.794) MHz.

 Filtered from out-of-band interference, the CPHC GPS signals converted to the first intermediate frequency (Fig. 4a, b) from the output of the filter 6 are fed to the signal input of the mixer 7, where the second frequency conversion of the CPHC GPS signals is performed.

For the second frequency conversion of the CPHC GPS signals carried out in the mixer 7 of channel 3, the second heterodyne frequency signal is used, which is synthesized in block 17 from the 10 MHz reference signal generated by the reference generator 20. In the first mode of operation of the inventive device, the signal frequency of the second heterodyne frequency is set f _r2 (1) = 181.5 MHz, and in the second, f _r2 (2) = 182.5 MHz.

 Filtered from out-of-band interference, the GLONASS signals CPHC converted to the first intermediate frequency (Fig. 4c, d) from the output of the filter 9 are fed to the signal input of the mixer 10, where the second frequency conversion of the CPHC GLONASS signals is performed.

For the second frequency conversion of the GLONASS CPHC signals carried out in the mixer 10 of channel 4, the third heterodyne frequency signal is used, which is generated in block 18 by dividing by eight the frequency of the first heterodyne frequency signal synthesized by block 16. In the first mode of operation of the inventive device, the frequency of the third heterodyne frequency signal it is set f _r3 (1) = 1/8 • f _r1 (1) = 176.5 MHz, and in the second - f _r3 (2) = 1/8 • f _r1 (2) = 176 MHz.

 As a result of the second frequency conversion, the position of the frequency bands occupied by the CPHC GPS and GLONASS signals on the frequency axis changes as shown in FIG. 5, where FIG. 5a is the location of the frequency bands of the CPHC GPS signals for the first mode of operation (13.99 - 22.17) MHz, FIG. 5b is the location of the frequency bands of the CPHC GPS signals for the second mode of operation (10.99 - 19.17) MHz, FIG. 5c shows the location of the frequency bands of the CPHC GLONASS signals for the first operating mode (11.46 - 22.29) MHz, FIG. 5d - location of the frequency bands of the CPHC GLONASS signals for the second mode of operation (12.02 - 22.29) MHz.

 Frequency-converted using the mixers 7, 10, the CPHC GPS and GLONASS signals in each of the channels 3, 4 are converted to digital form using the analog-to-digital conversion units 8, 11. The conversion of signals into digital form consists in amplifying the signals in the amplifying elements 12, 14 and quantizing the level in the threshold elements 13, 15.

 In preferred embodiments of the inventive device, said amplification is carried out using an amplifier with automatic gain control, and level quantization is performed using a two-bit quantizer. The case of amplification with an amplifier with a constant gain is also of practical importance, and level quantization with a binary quantizer. The choice of a specific implementation scheme of the amplifier and quantizer is determined by the digital correlator used for subsequent signal processing.

 From the outputs of the blocks 13, 14 analog-to-digital conversion, that is, from the outputs of channels 3, 4, the signals converted into digital form are fed to the output of the device.

 The output of the device also receives a clock signal generated by the block 19, which is part of the equipment 5.

 The output signals of the device then go to the multi-channel digital correlator of the navigation processor (not shown in Fig. 2) for further digital processing and separation of navigation information.

The formation of a clock frequency signal (clock signal) in the inventive device is carried out from the signal of the third heterodyne frequency generated by block 18, by dividing this frequency by eight. With the indicated generation of the clock signal, the clock frequency, which determines the frequency of time sampling during digital signal processing in the digital correlator, is F _T ≈ (176: 8) MHz = 22 MHz. This frequency is consistent with the range of output signals (GPS and GLONASS) of the device, which makes it possible to digitally process signals without loss of navigation information. At the same time, a decrease in the clock frequency compared to the prototype allows reducing the power consumed by the digital units (digital correlator and navigation processor units are not shown in the drawings). This is important when running portable (handheld) battery-powered transceivers.

 The operation mode of the device corresponding to the reception of CPHC GLONASS signals of a certain range of letter frequencies (i = 0-12 or i = -7-4) is set under the influence of external control commands received at the control inputs of blocks 16, 17, synthesizing the signals of the first and second heterodyne frequencies. External control commands can be formed, for example, in the navigation processor of the receiver, which includes this receiver. At the same time, setting the operating mode of the device does not require constructive improvement, in particular, it does not require reconfiguration of its band-pass filters.

 Thus, the claimed device solves the technical problem - it is possible within the same design of the receiving device to simultaneously receive and convert CPHC GPS and GLONASS signals of the frequency range L1 under the conditions introduced in accordance with [1] the new letter frequency ranges of the CPHC GLONASS signals, and namely - ranges with numbers of letters i = 0-12 and i = -7-4. In this case, the passband of the radio frequency path of the device is narrowed to the maximum, and the generated clock frequency, consistent with the spectra of the output signals, is reduced in comparison with the prototype. Setting the operation mode of the device corresponding to the range of used letter frequencies of the CPHC GLONASS signals is carried out without any replacement of the components and units of the device, including without replacing or tuning bandpass filters that determine the frequency selectivity and noise immunity of the receiver. The problem is solved using two (and not three, as in the prototype) synthesizers used to form the heterodyne frequencies, namely the synthesizers of the first and second heterodyne frequencies, while the signal of the third heterodyne frequency is formed from the signal of the second heterodyne frequency using a simple frequency divider by eight, and the clock signal from the signal of the third local oscillator frequency also using the frequency divider by eight (that is, without using a separate clock generator), which simplifies device execution.

 From the above it can be seen that the claimed invention is feasible, industrially applicable, solves the technical problem and has prospects for the use of portable transceivers that work simultaneously on the CPHC GPS and GLONASS signals and implement the "standard accuracy" of navigation locations. At the same time, it is possible to operate the receiver under the conditions of the indicated change of the letter frequency ranges of the CPHC GLONASS signals without constructive modification and modification of the device.

Sources of information
1. Global Navigation Satellite System - GLONASS. Interface control document. KNITS VKS Russia, 1995.

 2. Global Positioning System. Standard Positioning Service. Signal Specification. USA, 1993.

 3. Global Positioning System (GPS) Receiver RF Front End. Analog-Digitl Converter. Rockwell International Proprietary Information Order Number. May 31, 1995.

 4. Network satellite radio navigation systems / V.S.Shebshaevich, P.P. Dmitriev, N.V. Ivantsevich et al. - M.: Radio and Communications, 1993.

 5. Riley S., Howard N., Aardoom E., Daly P., Silvestrin P. A Combined GPS / GLONASS High Precision Receiver for Spase Applications / Proc. jf ION GPS-95, Palm Springs, CA, US, Sept. 12-15, 1995, p. 835-844.

 6. Moses I. Navstar Global Positioning System oscillator requirements for the GPS Manpack. Proc. of the 30th Annual Freguency Control Sympos., 1976, p. 390-400.

 7. A. J. Van Dierendonck, Pat. Fenton and Tom Ford. Theory and Performance of Narrow Correlator Spacing in a GPS Reciever. Navigation: Journal of The Institute of Navigation, vol. 39, N 3, 1982.

 8. US patent US N 5390207 (A1), CL. G 01 S 5/02, H 04 B 7/85, publ. 02/14/95.

 9. US patent US N 5495499 (A1), CL. H 04 L 9/00, publ. 02/27/96.

 10. Radio receivers / Banks V.N., Barulin L.G., Zhodzishsky M.I. et al., Moscow: Radio and Communications, 1984.

 11. Professional Products. IC Handbook. June 1994. GEC Plessey Semiconductors.

Claims (3)

 1. A device for receiving signals from satellite radio navigation systems, comprising an input unit including at least one band-pass filter connected to an output of an input unit of a first signal frequency conversion, including at least one mixer connected to an output of a first frequency conversion unit the first and second channels of the second signal frequency conversion, respectively, CPHC GPS and GLONASS, each of which contains a series-connected filter, the input of which is the channel input, an amplifier and an analog-to-digital conversion unit, the output of which is the channel output, as well as clock and heterodyne frequency signal generating equipment, comprising a first heterodyne frequency signal generating unit, a second heterodyne frequency signal generating unit, a third heterodyne frequency signal generating unit and a clock signal generating unit frequency, and the signal output of the first heterodyne equipment for generating signals of clock and heterodyne frequencies, formed by the output of the signal generating unit and the first heterodyne frequency, connected to the reference input of the mixer of the first signal frequency conversion unit, the output of the second heterodyne frequency signal, formed by the output of the signal generation unit of the second heterodyne frequency, is connected to the reference input of the mixer of the first channel of the second signal frequency conversion, and the signal output of the third heterodyne frequency, formed by the output of the third heterodyne frequency signal conditioning unit, connected to the reference input of the mixer of the second channel of the second frequency conversion signals, while the outputs of the first and second channels of the second signal frequency conversion and the output of the clock signal of the equipment for generating clock and local oscillation signals, formed by the output of the clock signal generating unit, are the outputs of the device, and the input of the input unit is the signal input of the device, characterized in that in the channels of the second signal frequency conversion, each of the analog-to-digital conversion blocks is made in the form of a series-connected amplifier element and In the apparatus for generating clock and heterodyne frequency signals, the clock signal generating unit is made in the form of a frequency division by eight unit, and the input of the clock signal generating unit is connected to the output of the third heterodyne signal generating unit in the form of an eight frequency division unit , the input of the signal conditioning unit of the third heterodyne frequency is connected to the output of the signal conditioning unit of the first heterodyne frequency, while the signal generating unit of the first g the local oscillator frequency and the second heterodyne frequency signal generation unit are made in the form of tunable frequency synthesizers, the reference inputs of which are connected to the output of the reference generator, and the control inputs form the control inputs of the device for realigning the device in conditions of changing the letter frequencies of the GLONASS SRNS.  2. The device according to p. 1, characterized in that the amplifier and threshold elements of the blocks of analog-to-digital conversion channels of the second signal frequency conversion are made in the form of an amplifier with automatic gain control and a two-bit quantizer in level.  3. The device according to claim 1, characterized in that the amplifier and threshold elements of the blocks of analog-to-digital conversion channels of the second signal frequency conversion are made in the form of an amplifier with a constant gain and a binary quantizer in level.

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