RU2145422C1 - Device for reception of signals of satellite positioning systems - Google Patents

Abstract

FIELD: radio engineering, in particular, receivers of global positioning systems. SUBSTANCE: device receives GPS numbered frequency signals within range of -7 to 4 or from 0 to 12 using single frequency synthesizer for production local oscillator frequencies. EFFECT: simultaneous reception of signals from several GPS systems. 11 dwg

Description

The invention relates to the field of radio navigation and can be used in the navigation equipment of consumers of satellite radio navigation systems (SRNS), and in particular, in radio receivers that simultaneously receive GPS and GLONASS signals in the frequency range L ₁ with code modulation, respectively, “open” "code in the GPS" SRNS "and the code" standard accuracy "in the GLONASS SRNS, while also converting the received SRNS signals to a form that allows for subsequent radio navigation measurements rhenium.

As you know, see for example [1, S. 13-15], [2, p. 35], the signals emitted by GPS artificial navigation satellites (NISS) of the GPS and using the "open" code for radio navigation measurements are radio signals transmitted in the frequency range L ₁ (carrier frequency 1575.42 MHz) and modulated by "C / A "phase code (0, π" C / A "code is generated according to the law of pseudorandom sequence (SRP) with a period of 1 ms and a clock frequency of 1,023 MHz. Code transmitted in the frequency range L ₁ " C / A ", also called a code" standard accuracy, "open to all consumers of navigation information and is used in radio navigation equipment of "standard accuracy", the class of which the claimed device belongs to. The frequency band of GPS signals "GPS", modulated by "C / A" code in the range L ₁ , is (1574.397 - 1576, 443) MHz [1 , p. 16], [2, p. 64, Fig. 4.3]. The location of the frequency band of GPS signals of the GPS range L _{1 is} shown in Fig. 1a (solid line), where the signal spectrum width is determined by the first zeros of the spectrum under modulation "C / A" code. To identify the signals emitted by various NEAs, the GPS GPS code division uses signals separation.

 In contrast to the GPS GPS, the GLONASS GPS, for example, see [2, p. 28-30], the frequency separation of the signals emitted by various NEAs is adopted.

The signals of the NISS SRNS "Glonass" are identified by the value of the nominal of their carrier ("letter") frequency lying in the allotted frequency range. Denominations of letter frequencies are formed according to the rule:
f _i = f ₀ + iΔf,
where f _i are the nominal values of the letter frequencies;
f ₀ - zero lettering frequency;
i - numbers of letter frequencies;
Δf is the interval between letter frequencies.

For frequencies of the range L ₁ (near 1600 MHz) - f ₀ = 1602 MHz, Δf = 0.5625 MHz.

 The distribution of letter frequencies among the functioning GLNASS SRNS SRNS is set by the almanac transmitted in the frame of service information.

 Letter frequencies are entered in accordance with the “Interface Control Document [3]”. Currently, letter frequencies from i = 0 to i = 12 have been introduced; further, in accordance with [3], the introduction and use of letter frequencies from i = -7 to i = 4 is provided.

For the purposes of standard navigational definitions, GLONASS SRNS signals in the L ₁ band are modulated with standard accuracy SRP code (with a clock frequency of 0.511 MHz) - similar to the C / A modulation code in GPS GPS.

The frequency band of the GLONASS SRNS signals, modulated with a standard accuracy code in the L ₁ range, for letter frequencies from i = 0 to i = 12 occupies the band (1601, 489 - 1609, 261) MHz (Fig. 1b, solid line), and for letter frequencies from i = -7 to i = 4, it occupies the range (1597, 5515 - 1604.76) MHz (Fig. 1c, solid line). The width of the frequency bands occupied by the GLONASS signals provided in FIG. 1a, b, is determined by the first zeros of the spectrum when modulated by a standard accuracy code, i.e. the boundaries of the frequency range L ₁ for the case of letter frequencies from i = 0 to i = 12 (lower f _n1 and upper f _b1 ) are determined based on the relations:
f _n1 = f ₀ -0.511 MHz = (1602-0.511) MHz = 1601, 489 MHz;
f _in1 = f ₁₂ + 0.511 MHz = (1608.75 + 0.511) MHz = 1609, 261 MHz,
and the boundaries of the frequency range L ₁ for the case of letter frequencies from i = -7 to i = 4 (lower f _n2 and upper f _b2 ) are determined based on the relations:
f _H2 = f _-7 -0.511 MHz = (1598.0625 -0.511) MHz = 1597, 5515 MHz;
f _H2 = f ₄ + 0.511 MHz = (1604.25 + 0.511) MHz = 1604, 761 MHz.

In order to reduce the noise error of tracking the code and to reduce errors associated with the multipath propagation of the signal, the subsequent digital processing of the received SRNS signals in the consumer equipment uses, as a rule, the “narrow” correlator method [4]. To implement this method of digital processing of SRNS signals, the radio receiving path must have a wider bandwidth, i.e. must pass the frequency band of the signals taking into account at least 2-4 petals on both sides of the carrier, respectively determined by 2-4 zeros in the signal spectrum for any letter frequency of the Glonass signal and all GPS system signals. The frequency band of the GLONASS SRNS signals determined in this way (using four zeros of the spectrum when modulated with a standard accuracy code in the range L ₁ ) for the case of letter frequencies from i = 0 to i = 12 occupies the range (1599.956 - 1610, 794) MHz ( Fig. 1b is a dashed line), and for the case of letter frequencies from i = -7 to i = 4, it occupies the range (1596.0185 - 1606, 294) MHz (Fig. 1c is a dashed line). The frequency band of GPS GPS signals in the L ₁ band, defined similarly using four zeros of the spectrum when modulated with a “C / A” code, occupies the band (1571.328 - 1579, 512) MHz (Fig. 1a is a dotted line).

 The differences that exist between the GPS and GLONASS SRNS signals due to code separation at one carrier in the GPS GPS and frequency division at several carriers determined by the letter frequencies in the GLONASS SRNS cause differences in technical means, using which receive signals from these SRNSs and convert them to a form that allows for subsequent radio navigation measurements.

 It is known, for example, from [5, FIG. 1], a device for receiving GPS signals "GPS", comprising a low-noise amplifier, a filter, a first mixer, an amplifier of the first intermediate frequency, a quadrature mixer, two quantizers for in-phase and quadrature channels, a signal conditioner of the first heterodyne frequency (1401.51 MHz), and also a division unit generating a second heterodyne frequency signal from a signal of the first heterodyne frequency. The device solves the technical problem of receiving and converting GPS 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 signals from the GLONASS SRNS.

 It is known, for example, from [2, p. 147-148, fig. 9.2], a device for receiving signals from the GLONASS SRNS, implemented as part of the ASN-37 single-channel consumer equipment. The device comprises 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, a letter frequency synthesizer, and heterodyne frequency drivers. The letter frequency synthesizer generates its output signals in accordance with the letter frequencies of the received GLONASS signals. The pitch of the letter frequencies generated by the synthesizer is 0.125 MHz. The signal of the first heterodyne frequency is formed by multiplying the frequency of the output signal of the synthesizer by four, and the signal of the second heterodyne frequency is formed by dividing the frequency of the output signal of the synthesizer by two. The device solves the technical problem of receiving and converting GLONASS signals to a form that allows the consumer to carry out appropriate radio navigation measurements. The device does not allow to solve the problem of receiving GPS-GPS signals.

Despite the above differences, existing between the GPS and Glonass SRNSs, their proximity to the ballistic construction of the orbital constellation of the NISS and the used frequency range, allows us to set and solve problems associated with the creation of integrated navigation equipment for consumers using the signals from these two SRNSs . The result achieved in this case is to increase the reliability, reliability and accuracy of determining the location of the object, in particular, due to the possibility of choosing the working constellations of the NISS with the best values of geometric factors [2, p. 160]. To the greatest extent, this result is important for equipment that determines the location by the signals of the frequency range L ₁ modulated by codes of standard accuracy.

It is known, see, for example, [2, p. 158-161, fig. 9.8], a device that solves the problem of receiving GPS and Glonass SRNS signals of the frequency range L ₁ 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 GPS and GLONASS signals, bandpass filters and low-noise amplifiers of GPS and GLONASS channels, a mixer, a microwave switch that connects SRNS signals to the signal input of the mixer “GPS” or “Glonass”, a microwave switch that connects to the reference input of the mixer the signal of the first local oscillator for the “GPS” channel or the “Glonass” channel. Due to the corresponding formation of the frequency of the heterodyne signal, the first intermediate frequency is constant for the GPS and GLONASS signals and the entire further path of the device is implemented as common to these signals.

 A feature of the device is that the reception and conversion of signals from each of the SRNS is carried out sequentially in time using the same radio channel, which increases the time spent in subsequent processing to obtain navigation information. In addition, the implementation of the device requires a complex in its implementation high-frequency switchable frequency synthesizer, which provides the formation of two different heterodyne signals used to convert the SRNS signals "GPS" and "Glonass", respectively.

A device for receiving signals SRNS "GPS" and "Glonass", described in [6, p. 835-844, FIG. 2], in which the problem of simultaneously receiving GPS and Glonass SRNS signals (letter frequencies from i = 1 to i = 24) was solved with their conversion to a form that allows subsequent radio navigation measurements using a digital processor. The functionally complete part of this device, which solves the problem of simultaneously receiving GPS and GLONASS signals of the L ₁ frequency band, is adopted as a prototype.

 A block diagram of a device adopted as a prototype is shown in FIG. 2.

 The device adopted as a prototype contains (Fig. 2) an input unit 1, the input of which is the signal input of the device, a unit 2 of the first signal frequency conversion, comprising in series connected an input amplifier 3, a mixer 4 and an intermediate frequency amplifier 5, the first 6 and second 7 channels of the second signal frequency conversion — respectively, GPS and Glonass SRNS signals, the outputs of which are device outputs, as well as a shaper (synthesizer) of 8 signals of the first heterodyne frequency and a clock signal shaper 9 new frequency.

 Channel 6 of the second signal frequency conversion comprises a first filter 10 connected in series, the input of which is the input of channel 6, a mixer 11, a second filter 12, and an analog-to-digital converter (ADC) 13, the output of which is the output of channel 6.

 Channel 7 of the second signal frequency conversion comprises a first filter 14 connected in series, the input of which is the input of channel 7, a mixer 15, a second filter 16 and an analog-to-digital converter (ADC) 17, the output of which is the output of channel 7.

 The inputs of the filters 10 and 14, respectively, of the first 6 and second 7 channels of the second signal frequency conversion are connected to the output of amplifier 5, that is, to the output of block 2 of the first signal frequency conversion. The input of amplifier 3, that is, the input of block 2, is connected to the output of block 1. The reference input of the mixer 4 of block 2 of the first signal frequency conversion is connected to the output of the signal former (synthesizer) 8 of the first heterodyne frequency. The clock inputs of the ADC 13 and 17, respectively, of the first 6 and second 7 channels of the second signal frequency conversion are connected to the output of the clock signal shaper 9. The reference inputs of the mixers 11 and 15, respectively, of the first 6 and second 7 channels of the second signal frequency conversion are connected to the outputs of two separate signal conditioners (synthesizers) of the second and third heterodyne frequencies (not shown in Fig. 2).

 The device, adopted as a prototype, works as follows.

The GPS and Glonass SRNS signals of the frequency range L ₁ from the input antenna (not shown in FIG. 2) through the input unit 1, which carries out frequency filtering of the signals of this frequency range, are fed to the input of block 2 of the first signal frequency conversion.

In block 2 of the first signal frequency conversion, the GPS and GLONASS signals of the frequency range L _{1 are} amplified in the input amplifier 3, converted in frequency in the mixer 4, and amplified in the intermediate frequency amplifier 5.

For the first frequency conversion, carried out in block 2, the prototype device uses the signal of the first heterodyne frequency f _g1 = 1416 MHz, synthesized by the shaper 8 of the signal of the first heterodyne frequency.

The converted signals are in unit 2 the SRNS "GPS" and "Glonass" frequency band L ₁ to the inputs of the first 6 and second 7 channels of the second signal frequency converter, i.e. to the inputs of filters 10 and 14. Each of these filters performs filtering of signals of one SRNS namely, filter 10 is a filtering of GPS “SRNS” signals, and filter 14 is a filtering of GLONASS SRNS signals.

 Filtered using filters 10 and 14 from out-of-band interference and separated by systems ("GPS" and "Glonass"), the frequency-converted signals in each of the channels 6 and 7 are fed to the signal inputs of the mixers 11 and 15, respectively.

For the second frequency conversion carried out in the channels 6 and 7 in the prior art device uses signals of the second and third heterodyne frequencies f _r2 = 173.9 MHz and f _r3 = 178.8 MHz synthesized corresponding formers (synthesizers) heterodyne frequencies (in Figure 2 not shown). When this signal of the second heterodyne frequency f _r2 = 173.9 MHz is used for conversion of SRNS "GPS" in the mixer 11 of the first channel 6 and the signal of the third heterodyne frequency f _r3 = 178.8 MHz is used for conversion of SRNS signals "Glonass" mixer 15 of the second channel 7.

 The GPS and GLONASS signals converted by means of mixers 11 and 15 in each of channels 6 and 7 are filtered using filters 12 and 16, and then converted to digital form using ADCs 13 and 17.

 The clock frequency that determines the frequency of analog-to-digital conversion (i.e., the sampling frequency in time) is 57.0 MHz in the prototype device - from the condition for eliminating the loss of navigation information contained in the received signals when converting signals from an analog form to digital .

The values of heterodyne frequencies f _r2 = 173.9 MHz and f _r3 = 178.8 MHz for the second conversion of frequency of signals in prototype ustroystve- selected so that the average frequency signals SRNS "GPS" and "Glonass" on the second intermediate frequency would be close to 14.25 MHz. This circumstance is due to the peculiarities of the digital signal processing used in the prototype, where the clock frequency of the 4-bit ADC is chosen equal to f _t = 57.0 MHz (4 • 14.25 MHz) and specialized digital filters are used that select two-bit in-phase and quadrature samples with a frequency 28.5 MHz (2 • 14.25 MHz) [6, p. 837].

With the output of the ADCs 13 and 17, the frequency-converted and digitally presented GPS-and GLONASS signals of the frequency range L ₁ are transmitted to the first and second outputs of the device. The output signals of the device are further processed in a digital navigation processor (not shown in FIG. 2) to obtain navigation information.

The solutions implemented in the prototype device for the frequency conversion of the received signals are based on the absence of restrictions imposed on the number of synthesizers used to generate the heterodyne frequency signals. Indeed, in the prototype device, three heterodyne signals are used: the first with a frequency of 1416 MHz, the second with a frequency of 173.9 MHz, and the third with a frequency of 178.8 MHz. None of these heterodyne frequencies can be obtained from another heterodyne frequency used in the prototype device by simple multiplication or division. Therefore, heterodyne frequencies are synthesized using three separate generators (synthesizers) of heterodyne frequencies, each of which is an independent radio engineering device that is difficult to implement. The complexity of the heterodyne frequency synthesizers used in devices for receiving SRNS signals is due to the high requirements for the stability of the synthesized frequencies (relative frequency instability 10 ^-11 - 10 ^-12 for 1 s [7]), since the output characteristics depend on this to a large extent receiving device as a whole.

 In this regard, the urgency of the task of simplifying heterodyne equipment, for example, reducing the number of frequency synthesizers, is obvious. The possibility of simplifying the receiving device as a whole depends on the solution of this problem, which is important, for example, for constructing a receiving device that receives and converts GPS and GLONASS SRNS signals as a part of on-board radio navigation equipment, and especially as part of portable (pocket-sized) receiver-indicators intended for mass use by a wide range of users.

 Another urgent task, which was not posed and not solved in the prototype device, is the task of ensuring the possibility of receiving GLONASS signals with additional (from -7 to 0) letter frequencies entered in accordance with the “Interface control document” [3], with minimal technical costs and without significant complexity of the equipment. Indeed, the solution to this problem, which follows from the need to ensure the life cycle of the device in conditions of changing the numbers of the letter frequencies of the GLONASS SRNS signals introduced in accordance with [3], is impossible within the framework of the solutions implemented in the prototype device without increasing the sampling clock frequency and changes in the nominal values of heterodyne frequencies, which is associated with the complication of synthesizers of heterodyne frequencies, for example, making them tunable.

The objective of the invention is the creation of a device that simultaneously receives and converts SRNS signals "GPS" and "Glonass" modulated with standard accuracy codes in the L ₁ range, using one synthesizer to generate heterodyne frequencies, with the possibility of receiving and processing SRNS signals "Glonass "under the conditions of a change in accordance with [3] the numbers of the letter frequencies of the GLONASS SRNS signals (i = 0 - 12 or i = -7 - 4), moreover, the restructuring of the device under the conditions of changing the letter frequencies should be to operate under the influence of an external logic control signal.

 In addition, the inventive device should make it possible to maintain the signal processing mode in the "narrow" correlator, receiving and processing an expanded, taking into account several side lobes, spectrum of GPS and Glonass SRNS signals, modulated by "C / A" code and code " standard accuracy, respectively.

 The essence of the invention lies in the fact that the device for receiving signals from satellite radio navigation systems (SRNS), containing an input unit, the input of which is the signal input of the device, the unit for the first signal frequency conversion, the first and second channels of the second signal frequency conversion, the outputs of which are the first and the second outputs of the device, respectively, the GPS and GLONASS signals, as well as the driver of the first heterodyne frequency signal and the driver of the clock signal, while the block of the first The signal frequency conversion comprises an input amplifier connected in series, the input of which is connected to the output of the input unit, a mixer, the reference input of which is connected to the output of the signal generator of the first heterodyne frequency, and an intermediate frequency amplifier, the output of which is connected to the inputs of the first and second channels of the second signal frequency conversion, each of which contains a first filter connected in series, the input of which is a channel input, a mixer, a second filter and an analog-to-digital converter The driver, the output of which is the channel output, and the clock input is connected to the output of the clock frequency driver, an additional frequency division unit with a constant frequency division factor of eight and a frequency division unit with a switchable frequency division coefficient of seven or eight, the signal inputs of which are connected to the output of the driver of the signal of the first heterodyne frequency, while the reference input of the mixer of the first channel of the second signal frequency conversion is connected to the output of the frequency division unit with oyannym coefficient of frequency division by eight, and the reference input of the mixer of the second channel of the second conversion of frequency of signals is connected to the output of the frequency divider with switchable frequency division factor of seven or eight, which control input is a control input device.

The essence of the claimed device, the possibility of its implementation and industrial use are illustrated by drawings and frequency diagrams presented in FIG. 1 - 5, where:
in FIG. Figure 1 presents frequency diagrams explaining the distribution of the frequency bands of the GPS (GPS) signals (Fig. 1a) and Glonass with letter frequencies from i = 0 to i = 12 (Fig. 1b) and with letter frequencies from i = -7 to i = 4 (Fig. 1 c);
in FIG. 2 shows a block diagram of a device adopted as a prototype;
in FIG. 3 shows a structural diagram of the inventive device;
in FIG. 4 are frequency diagrams explaining the distribution of the frequency bands of the GPS (GPS) signals (Fig.4a) and Glonass with the letter frequencies from i = 0 to i = 12 (Fig.4b) and with the letter frequencies from i = -7 to i = 4 (pigv) after the first frequency conversion in the inventive device;
in FIG. 5 are frequency diagrams explaining the distribution of the frequency bands of the GPS (GPS) signals (Fig.5a) and Glonass with letter frequencies from i = 0 to i = 12 (Fig.5b) and with letter frequencies from i = -7 to i = 4 (Fig. 5B) after the second frequency conversion in the inventive device.

 The inventive device comprises, see FIG. 3, the input unit 1, the input of which is the signal input of the device, the first signal frequency conversion unit 2, which contains the input amplifier 3, the mixer 4 and the intermediate frequency amplifier 5, the first 6 and second 7 channels of the second signal frequency conversion, the outputs of which are the first and the second outputs of the device, respectively, the SRNS signals "GPS" and "Glonass", the driver 8 of the signal of the first local oscillator frequency and the driver 9 of the clock signal.

 Channel 6 of the second signal frequency conversion comprises a first filter 10, a mixer 11, a second filter 12, and an analog-to-digital converter (ADC) 13 connected in series, the output of which is the output of channel 6.

 Channel 7 of the second signal frequency conversion comprises in series a first filter 14, a mixer 15, a second filter 16, and an analog-to-digital converter (ADC) 17, the output of which is the output of channel 7.

 The inputs of the filters 10 and 14, which are inputs of the first 6 and second 7 channels of the second signal frequency conversion, respectively, are connected to the output of amplifier 5, that is, to the output of block 2 of the first signal frequency conversion.

 The input of amplifier 3, that is, the input of block 2 of the first signal frequency conversion, is connected to the output of block 1.

 The reference input of the mixer 4 of the block 2 of the first signal frequency conversion is connected to the output of the signal former 8 of the first heterodyne frequency.

 The clock inputs of the ADC 13 and 17 of the first 6 and second 7 channels of the second signal frequency conversion are connected to the output of the clock driver 9.

 The inventive device also includes a frequency division unit 18 with a constant frequency division coefficient by eight and a frequency division unit 19 with a switchable frequency division coefficient by seven or eight, the control input of which is the control input of the device.

 The signal inputs of the frequency division units 18 and 19 are connected to the output of the driver 8 of the signal of the first heterodyne frequency.

 The reference input of the mixer 11 of the first channel 6 of the second signal frequency conversion is connected to the output of the frequency division unit 18 with a constant frequency division coefficient by eight, and the reference input of the mixer 15 of the second channel 7 of the second signal frequency conversion is connected to the output of the frequency division unit 19 with a switched frequency division coefficient by seven or eight.

 The input unit 1 of the claimed device is a well-known filtering device widely used in the SRNS signal reception technique, implemented, for example, in the form of a filter on disk dielectric resonators [8, p. 58, fig. 2.20].

 The input amplifier 3 of block 2 of the first signal frequency conversion can be implemented according to the well-known low-noise amplifier transistor with a common emitter, described, for example, in [9, p. 241, fig. 8.12].

 The mixer 4 of the block 2 of the first signal frequency conversion is a device known in the art of receiving and processing SRNS signals, made according to the balanced diode mixer scheme, described in particular in [9, p. 258 - 260, fig. 8.25].

 The amplifier 5 of the intermediate frequency of unit 2 of the first signal frequency conversion can be implemented, for example, according to the well-known circuit of the amplifier on a differential stage with a “common emitter - common base” described in [9, p. 137-141, fig. 5.5].

 Filters 10 and 14 of the first 6 and second 7 channels of the second signal frequency conversion, which are single band-pass filters, can be implemented, for example, according to the well-known scheme described in [9, p. 217-220], in the form of filters on surface acoustic waves.

 Mixers 11 and 15 of the first 6 and second 7 channels of the second signal frequency conversion can be performed, for example, according to the analog multiplier scheme described in [9, p. 156-158, fig. 5.13].

 Filters 12 and 16 of the first 6 and second 7 channels of the second signal frequency conversion can be made in the form of band-pass filters on LC elements according to the scheme described, for example, in [10, p. 85, fig. 4.04.1], with a design compatible with microelectronic components [9, p. 183-188].

 Analog-to-digital converters (ADCs) 13 and 17 of the first 6 and second 7 channels of the second signal frequency conversion can be implemented according to the well-known parallel ADC circuit described in particular in [11, pp. 41–45, Fig. 2.5].

The driver 8 of the first heterodyne frequency signal can be implemented, for example, according to the well-known frequency synthesizer circuit "1.3 / 1.5 GHz low power single-chip frequency synthesiser SP8853" described in [12, p. 2-3 ^o C 2-14, FIG. 6].

 The clock signal generator 9 can be implemented, for example, according to the well-known scheme "A Serial Programmable VHF Frequency Synthesiser" described in [12, p. 4-46, FIG. 1].

 The frequency division unit 18 with a constant frequency division factor of eight can be performed, for example, according to the well-known high-frequency divider circuit described in [12, pp.3-158, figure 2], and implemented on a standard chip type "SP8808" (" 3.3 GHz - 8 Fixed Modulus Divider ").

 The frequency division unit 19 with a switchable frequency division coefficient by seven or eight can be performed, for example, as a high-frequency frequency divider with feedback controlled by an external potential signal, similarly to the circuit described in [12, p. 3-48, FIG. 2] and implemented on a standard microcircuit type SP8743B.

The operation of the claimed device will be considered on the example of reception and conversion of SRNS signals "GPS" and "Glonass", modulated with standard accuracy codes in the range L ₁ , for the case when the signals of SRNS "Glonass" are signals with letter frequencies from i = 0 to i = 12 or from i = -7 to i = 4.

 The inventive device operates as follows.

Received by the input antenna (not shown in FIG. 3), the GPS and GLONASS signals of the frequency range L ₁ are received at the input of input block 1.

GPS signals of the L ₁ band occupy frequency bands with a width of ΔF = 8.184 MHz (four lobes in the signal spectrum on both sides of the carrier), and GLONASS signals of a L ₁ band occupy frequency bands of ΔF = 10.838 MHz (the case of letter frequencies from i = 0 to i = 12) and ΔF = 10.2755 MHz (the case of letter frequencies from i = - 7 to i = 4). The position of the frequency bands occupied on the frequency axis by the GPS and GLONASS signals in the case under consideration is shown by a dotted line in FIG. 1, where FIG. 1a is the frequency band of the GPS GPS signals of the range L ₁ - (1571.328-1579.512) MHz, FIG. 1b is the frequency band of the GLONASS SRNS signals of the L ₁ range for the case of letter frequencies from i = 0 and i = 12 - (1599.956 - 1610, 794) MHz, FIG. 1c - frequency band of the GLONASS SRNS signals of the L ₁ range for the case of letter frequencies from i = -7 to i = 4 - (1596.0185 - 1606, 294) MHz.

The input unit 1 transmits to its output the GPS and GLONASS signals of the L ₁ band _{of the} indicated frequency bands (that is, from 1571, 328 MHz to 1610, 794 MHz).

 The signals from the output of unit 1 are amplified in a low-noise input amplifier 3 of block 2 of the first signal frequency conversion, converted into a mixer 4 and amplified in an intermediate frequency amplifier 5.

For the first frequency conversion, carried out in block 2 of the claimed device, the signal of the first heterodyne frequency f _g1 = 1414 MHz, synthesized by the former 8 is used.

As a result of the first frequency conversion, the position of the frequency bands occupied by the GPS and GLONASS GPS signals changes on the frequency axis as shown in FIG. 4, where FIG. 4a is the location of the frequency bands of the GPS GPS signals of the range L ₁ - (157.328 - 165.512) MHz; 4b is the location of the frequency bands of the GLONASS SRNS signals of the L ₁ range for the case of letter frequencies from i = 0 to i = 12 - (185.956 - 196.794) MHz, FIG. 4c is the location of the frequency bands of the GLONASS SRNS signals of the L ₁ range for the case of letter frequencies from i = -7 to i = 4 - (182.0185 - 192.294) MHz.

From the output of the intermediate frequency amplifier 5, the converted GPS and GLONASS signals of the L ₁ range are fed to the inputs of the filters 10, 14 of the first 6 and second 7 channels of the second signal frequency conversion. Filters 10, 14 carry out band-pass filtering of signals from out-of-band interference.

 Filter 10 of the first channel 6 (that is, the GPS GPS signal channel) implements the characteristic of a band-pass filter with a band of 8.184 MHz and a center frequency of 161.42 MHz.

 The filter 14 of the second channel 7 (that is, the GLONASS SRNS signal channel) implements the characteristic of a band-pass filter with a band defined as 196.794 - 182.0185 = 14.7755 MHz and a center frequency of 189.4 MHz. The filter 14 passes the signals of the SRNS "Glonass" with letter frequencies from i = -7 to i = 12.

The frequency-converted GPS signals of the L ₁ band of frequency-converted from out-of-band interference (Fig. 4a) from the output of the filter 10 are fed to the signal input of the mixer 11, where the second frequency conversion of the GPS GPS signals is performed.

Filtered from out-of-band interference frequency-converted GLONASS SRNS signals of the L ₁ range (Fig. 4b, c) from the output of the filter 14 are fed to the signal input of the mixer 15, where the second frequency conversion of the GLONASS SRNS signals is performed.

As an LO signal to perform the second transformation "GPS" used frequency signals SRNS signal of the second heterodyne frequency f _r2 = 1/8 • f _r1 = 176,75MGts (FIG. 4a) formed in the claimed device, the signal of the first heterodyne frequency by block dividing the frequency 18 with a constant dividing factor of eight.

As the heterodyne signal for the second frequency conversion of the GLONASS SRNS signals, the third heterodyne frequency signal is used, namely the frequency signal f _g3 = 1/8 • f _g1 = 176.75 MHz (Fig. 4b) for the case of letter frequencies from i = 0 to i = 12 or a frequency signal f _g3 = _1/7 • f _g1 = 202 MHz (Fig. 4c) for the case of letter frequencies from i = - 7 to i = 4.

 The signal of the third heterodyne frequency is generated in the inventive device from the signal of the first heterodyne frequency using the frequency division unit 19 with a variable frequency division coefficient by seven or eight, while the desired division coefficient in block 19 is established as a result of applying to its control input (i.e., to the control input of the device) control signal - a potential logical signal "0" or "1".

As a result of the second frequency conversion, the position of the frequency bands occupied by the GPS and GLONASS GPS signals changes on the frequency axis as shown in FIG. 5, where FIG. 5a - frequency bands of the GPS GPS signals of the L ₁ - (11.238 - (19.422) MHz band, Fig. 5b - frequency bands of the GLONASS SRNS signals of the L ₁ band with letter frequencies from i = 0 to i = 12- (9,206 - 20,044) MHz, Fig. 5c - frequency bands of the GLONASS SRNS signals of the L ₁ range with letter frequencies from i = -7 to i = 4 - (19.9815 - 9.706) MHz.

The GPS and Glonass SRNS signals converted by means of mixers 11 and 15 of the L ₁ range in each of the channels 6 and 7 of the second signal frequency conversion are filtered by the corresponding bandpass filters 12 and 16, the transmission frequencies of which lie in the frequency range 10 - 20 MHz ΔF = 10 MHz).

 The GPS and GLONASS signals filtered by filters 12 and 16 are then converted to digital form using the ADCs 13 and 17.

 The clock frequency that determines the frequency of the analog-to-digital conversion (i.e., the sampling frequency in time) in the inventive device is selected in the range of 20 MHz, which is set based on the recommendations [11, p. 15-17], taking into account the fact that the bands of signals converted to digital form do not exceed 10 MHz at the output of filters 12 and 16 (Fig. 5a, b, c).

From the outputs of the ADCs 13 and 17, the frequency-converted and digitally presented signals of the GPS and Glonass SRNSs of the L ₁ range are received respectively at the first and second outputs of the device.

 The output signals of the device are processed in "narrow" correlators, and then in a digital navigation processor to obtain navigation information (not shown in Fig. 3).

 A previous review of the operation of the device was carried out under the assumption that its path provides the possibility of passing GPS and GLONASS signals taking into account the width of the spectrum, determined by the fourth zeros (four spectrum lobes on both sides of the carrier).

 It is obvious, however, that for the GLONASS signals of the lettered frequency i = 0 and partially for i = 1 (Fig. 5b), the boundary of the spectrum thus determined — 9.206 MHz — goes beyond the band limited by the frequency point 10 MHz (the beginning of the filter passband 16 ), by about 0.8 MHz, and for i = 4, the spectrum boundary of 9.706 MHz goes beyond the band limited by the 10 MHz frequency point by about 0.3 MHz. However, with a certain modification of the "narrow" correlators, information loss during subsequent correlation processing is excluded. Indeed, a frequency band located from 10 to 20 MHz can be processed without loss of information as a result of time sampling in an ADC with a clock frequency of 20 MHz. At the same time, restricting ourselves to two (instead of four) lobes in the spectrum of the GLONASS SRNS signals at the letter frequency i = 0 for correlation processing, it can be shown that the boundary of the spectrum moves to the right along the frequency axis by 2 • 0.511 MHz and amounts to 9.206 + 2 • 0.511 = 10.228 MHz. In this case, the entire processed signal spectrum lies in the frequency window (10 - 20) MHz. Similarly, for the GLONASS signals of the lettered frequency i = 4, if we restrict ourselves to three spectrum lobes during correlation processing, the lower boundary of the processed frequency range will be 9.706 + 0.511 = 10.217 MHz, which also lies in the frequency window (10 - 20) MHz. Similarly, for the GLONASS signals of the lettered frequency i = 1 during correlation processing should be limited to three spectrum lobes.

 Thus, for the GLONASS signals of the indicated letter frequencies, “narrow” correlators with a reduced number of lobes in the spectrum of the processed signal should be used. The GLONASS SRNS signals of all other letter frequencies, as well as all GPS GPS signals, can be processed without restriction in a “narrow” correlator with four lobes in the signal spectrum on both sides of the carrier. Such a solution, based on the use of these modifications of "narrow" correlators for processing GLONASS signals of the indicated letter frequencies, significantly simplifies the claimed device and does not lead to information loss during subsequent processing.

 Thus, the claimed device solves the technical problem — simultaneous reception and conversion of the GPS and Glonass SRNS signals with letter frequencies from i = -7 to i = 4 or from i = 0 to i = 12 is carried out using one frequency synthesizer (and not three as in the prototype) for generating heterodyne frequencies. This simplification of the heterodyne equipment can reduce the size and simplify the implementation of the inventive receiving device as a whole. The indicated positive feature of the claimed device along with another feature is the ability to receive signals with an extended range of letter frequencies, namely from i = -7 to i = 4 or from i = 0 to i = 12 (carried out by switching the division factor of the frequency divider 19 generating a heterodyne signal for the second frequency conversion of the GLONASS SRNS signals) determine the prospects of the claimed device for use as a part of modern on-board radio navigation equipment and small-sized portable equipment, such as portable (handheld) transceivers.

 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 navigation devices as part of the navigation equipment, operating simultaneously on the signals of two GPS and Glonass SRNS.

Sources of information
1. Kudryavtsev I.V. Mishchenko I.N., Volynkin A.I., et al. On-board devices of satellite radio navigation -M.: Transport, 1988.

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

 3. Global navigation satellite system. Interface control document (third edition). -M.: Coordination Scientific Information Center of the Aerospace Defense Ministry of the Russian Federation, 1995.

 4. A.J. Van Dierendonck, Pat Fenton, Tom Ford "Theory and Performance of Narrow Correlator Spacing in a GPS Receiver". / Navigation: Journal of The Institute of Navigation. Vol. 39, No. 3, Fall 1992.

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

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

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

 8. Gassanov L.G., Lipatov A.A., Markov V.V., Mogilchenko N.A. Solid-state microwave devices in communication technology. -M .: Radio and communications, 1988.

 9. Banks V.N., Barulin L.G., Zhodzishsky M.I. and other radio receivers. -M .: Radio and communications, 1984.

 10. Matthew D.L., Young L., Depons E.M.T. Microwave filters, matching circuits and communication circuits. -M.: Communication, 1971.

 11. Zhodzinsky M.I., Mazepa RB, Ovsyannikov EP et al. Digital radio receiving systems. Directory. -M .: Radio and communications, 1990.

 12. Professional Products IC Handbook May 1991. GEC Plessey Semiconductors.

Claims (1)

 A device for receiving signals from satellite radio navigation systems, comprising an input unit, the input of which is a signal input of the device, a unit for first converting signal frequencies, first and second channels of a second signal frequency conversion, the outputs of which are the first and second outputs of the device for receiving signals from satellite radio navigation systems "GPS "and" Glonass ", respectively, as well as a driver of a signal of the first local oscillation frequency and a driver of a signal of clock frequency, while the block of the first converter The frequency of the signal contains a series-connected input amplifier, the input of which is connected to the output of the input unit, a mixer, the reference input of which is connected to the output of the signal conditioner of the first heterodyne frequency, and an intermediate frequency amplifier, the output of which is connected to the inputs of the first and second channels of the second signal frequency conversion, each of which contains a series-connected first filter, the input of which is the channel input, a mixer, a second filter and an analog-to-digital converter the output of which is the output of the channel, and the clock input is connected to the output of the driver of the clock signal, characterized in that the device is additionally introduced a frequency division unit with a constant frequency division coefficient by eight and a frequency division unit with a switched frequency division coefficient by seven or eight, the signal inputs of which are connected to the output of the driver of the signal of the first heterodyne frequency, while the reference input of the mixer of the first channel of the second signal frequency conversion is connected to the output a frequency division unit with a constant coefficient of frequency division by eight, and the reference input of the mixer of the second channel of the second signal frequency conversion is connected to the output of the frequency division unit with a switchable frequency division coefficient of seven or eight, the control input of which performs the device rebuilding under changing letter frequencies, is the control input of the device.

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