RU105098U1 - DATA-TRANSFER EQUIPMENT FOR SATELLITE DATA COLLECTION AND TRANSMISSION SYSTEMS - Google Patents

Abstract

 1. Data transmission equipment of a satellite data acquisition and transmission system consists of a directional antenna, a low-directional antenna, a transmitter whose output is connected to the directional antenna input or a low-directional antenna input, respectively, a GPS navigation receiver, or GLONASS, or GLONASS / GPS, which constructively can be made in a single housing together with a receiving antenna or separately from the receiving antenna, a PC, which includes software that controls the operation of the navigation GPS, or GLONASS, or GLONASS / GPS and transmitter, the first PC I / O is connected to the inputs / outputs of the GPS navigation receiver, or GLONASS, or GLONASS / GPS, the second PC I / O is connected to the transmitter inputs / outputs, uninterruptible power supply connected to the transmitter, PC and the GPS navigation receiver, or GLONASS, or GLONASS / GPS, the monitor, keyboard and mouse are also connected to the PC. ! 2. The data transmission equipment according to claim 1, characterized in that the transmitter consists of a reference oscillator, a phase modulator, the first input of which is connected to the output of the reference generator, a synthesizer, consisting of a first frequency divider, a second frequency divider and a phase comparator of the synthesizer, the first the input of the first frequency divider is connected to the output of the phase modulator, the output of the first frequency divider is connected to the first input of the phase synthesizer, the second input of which is connected to the output of the second frequency divider, low-pass filter the signal whose input is connected to the output of the phase comparator of the synthesizer, a voltage-controlled generator, the first input of which is connected

Description

The utility model relates to the field of space communications technology and can be used to transmit information (digital message) for meteorological, environmental, and natural resources, the object’s ownership code, as well as exact coordinates from stationary and moving ground objects through low-orbit or geostationary spacecraft acquisition and transmission systems data (hereinafter referred to as JCSS)

The proposed data transmission equipment (hereinafter APD) will provide time-synchronized, continuous and long-term (up to 10-15 years) transmission of digital messages (telegrams) from 1 to 669 bytes in volume from land-based stationary objects to the center of the data acquisition system. The ADF will provide the formation with high accuracy of the moment of transmission and the repetition period of the message by synchronizing the time of the PC control included in the ADF, by the signal of the GPS or GLONAS or GPS / GLONASS navigation receiver, thereby ensuring high performance (the number of simultaneously serviced ADFs) of the acquisition and transmission system data both low-orbit and geostationary. The ADF provides a choice of letters of the carrier frequency and message transfer speed, which significantly increases the reliability of information transmission under the influence of ground interference in the APD-KA radio link (hereinafter the spacecraft).

From the patent RU 68139 of November 10, 2007 the emergency radio beacon of the space search and rescue system COSPAS-SARSAT is known, which includes a navigation receiver and is intended to transmit in the message the exact coordinates from the navigation receiver. An emergency radio beacon of known design includes a switching device, a transmitting antenna, a radio module, which includes a switching device, a program-time device, a digital signal transmitter, an autonomous power supply unit and a global navigation satellite system receiver with a receiving navigation antenna. Either the navigation receiver of the global GPS navigation system, or the navigation receiver of the global navigation system GLONASS, or the combined receiver of the global navigation system GLO-HACC / GPS is used as a receiver of the global navigation satellite system.

The beacon known from the patent RU 68139 has an autonomous single-acting battery pack, which greatly increases the cost of operation, since it requires periodic replacement of batteries due to aging. The disadvantage of the beacon is that the message of the beacon does not have an exact reference to the moment of radiation according to the signal of the GPS or GLONASS / GPS navigation receiver, and the message format can be partially changed no more than once every 15 minutes. As a rule, the operating time of a beacon for radiation does not exceed 24 hours, which is sufficient to rescue those in distress, but not enough for long-term collection of meteorological information or to determine the path of movement of a moving object, for example, a sea vessel.

Closest to the invention is a beacon of a space search and rescue system known from patent RU 61436 dated 10.25.2006, intended for continuous and long-term generation of a pulsed radio signal (packages) necessary for autonomous determination of the orbit parameters of low-orbit satellites at stations for receiving and processing information of the COSPAS system -SARSAT, as well as for monitoring the operability of onboard radio complexes of the satellite of the COSPAS-SARSAT system. A beacon (orbitographic beacon) includes a transmitting antenna with linear or right circular polarization, a monoblock, an external power source, and a rubidium frequency standard. The monoblock includes an internal reference generator, a control and switching unit, a transmitting device, a secondary power source, and a program-time device. The control and switching unit and the program-time device are connected to the transmitting device. The control and switching unit switches the signals to the transmitting device either from the internal reference generator or from the external reference generator, which is the rubidium standard, of the frequency. The power supply of the monoblock is carried out either from the ~ 220 V / 50 Hz network and the internal secondary power source, or from an external power supply, the power supply is switched by the control and switching unit automatically when the ~ 220 V / 50 Hz network fails from the external power supply. The software temporary device generates a digital message beacon and the repetition period of the parcels. The beacon has increased carrier frequency stability, a fixed repetition period of parcels of 30 s and operates continuously 24 hours an hour, 365 days a year and is installed in a precisely known place.

A disadvantage of the beacon known from patent RU 61436 is that the contents of the packages (digital message), which are unchanged in time, cannot be changed. The presence of a rubidium frequency standard in the beacon greatly increases the cost of a beacon, and modern thermostatically controlled reference generators with a cost of 5-10 less than the rubidium frequency standard have long-term stability of at least 5 × 10 ^-7 for 10 years, short-term frequency stability (Allan variation) is not more than 3 × 10 ^-11 in 1 s, linear frequency drift of not more than ± 2 × 10 ^-9 in 1 min and the standard deviation from linear drift of less than 3 × 10 ^-10 .

The technical result of the proposed device is the development of a universal ADF, providing continuous round-the-clock transmission of telegrams in the data transmission system via low-orbit spacecraft Meteor-M, Sterkh and geostationary spacecraft Electro-L, Luch-5A and Meteosat. The ADF will provide the formation of a signal with the required stability of the carrier frequency, signal level, phase modulation value over a long period of operation to transmit collected information to Earth through a satellite communication channel and determine the ADF coordinates. The operation of the ADF in the low-orbit and geostationary data acquisition and transmission system is provided by the transmitter unit, which, under the control of a PC, forms a carrier frequency letter, information transfer speed, the duration of the pure carrier radiation section and a digital message. The use of two types of antennas as part of the ADF — unidirectional for operation in the low-orbit SSPD system (hereinafter referred to as the SSPD) and directed to work in the geostationary SSPD system (hereinafter the SSPD GS) provides the universality of the use of the ADP with different spacecraft.

The claimed utility model will eliminate the shortcomings of the known technical solution and will allow transmitting information from stationary ADFs to the ND and GS DSS, and by selecting the carrier frequency letter and changing the transmission speed of the message, it will significantly increase the reliability of information transmission under the influence of interference from ground sources in the APD-KA radio link in the range of 401-403 MHz. The control from the PC will provide flexibility in the formation of the structure of the transmitted message regarding the application of various types of noise-proof coding to increase the reliability of information transfer. Using a GPS or GLONASS or GLONASS / GPS navigation receiver, the PC system time will be synchronized with Moscow winter time and thereby will allow to form the start of the radiation of a digital message from each ADF installed anywhere on the Earth with high accuracy during the entire operating time. Synchronization of the time of the radiation moment of each ADF will provide the number of simultaneously serviced ADFs in the BOTTOM from 1500 to 8000 pcs. depending on the duration of the transmitted digital message (“short” or “long”) with a uniform distribution of the ADF around the globe. In the GS SPD, synchronization of the time of the radiation moment will ensure the number of simultaneously serviced ADFs up to 160 thousand pieces, provided that the digital message is transmitted at the allocated synoptic dates (every three hours, for example, at 0, 3, 6, 9, 12, 15, 18, 21 h), the uniform distribution of the ADF on the surface of the Earth and the use of all 1333 frequency letters in the range 401-403 MHz.

The technical result expected from the use of the proposed technical solution is achieved by the fact that the proposed ADF containing a transmitter and two transmitting antennas are unidirectional and directional. Additionally, the ADF contains a PC, an uninterruptible power supply and a navigation receiver with a receiving antenna. In this case, the navigation receiver is a receiver of GPS or GLONASS or GLONASS / GPS navigation systems or any other receiver that combines well-known navigation systems. The navigation receiver can be structurally made in the housing together with the receiving antenna or separately from the receiving antenna and connected to the external receiving antenna with a cable from 3 to 50 meters. The navigation receiver is connected to the COM port of the PC or to the USB input. Moreover, the power supply to the navigation receiver can be carried out either from an external additional power source operating from an uninterruptible power supply or from a PC via the USB bus. The power supply of all ADF elements is provided from an alternating current network of -220 V / 50 Hz through an uninterruptible power supply.

The APM transmitting unidirectional and directional antenna are external antennas with respect to the transmitter, the output of which is connected to the antenna input of the directional or the input of the antenna unidirectional, respectively, through a high-frequency cable with low losses (0.1-0.05 W per 1 m in the 400 MHz band) length 10-15 m.

The software (hereinafter referred to as the software) included in the PC provides the transmitter control, namely, it generates digital messages that contain: a section of clean carrier, clock and frame synchronization, such as ADF, APD numbers and information about the data encoded in the KOI-7 code. The PC software provides the encoding of the ADF number and data field with an anti-interference code, the calculation of the visibility of the spacecraft according to the initial conditions of the spacecraft received from the Internet in the form of NORAD to transmit a digital message to the spacecraft only when the spacecraft are in the sight of the radio frequency detectors. The software works in the operating system Windows XP, Windows Vista or Windows 7.

The interface for entering information by the operator has a multi-window structure with the ability to save the typed messages for at least six months on the PC hard drive. The operator can arbitrarily form the following parameters for transmitting digital messages, namely: message length, APD-402 number, digital message repetition period, carrier frequency letter (a total of 35 letters in the range from 401.00 MHz to 403.00 MHz) message transmission , message transfer rates (100, 400, and 1200 bauds), encoding the number (address) fields, and information with the KOI code 7.

PC software provides PC time synchronization using the navigation receiver when starting the software or once a day at any time set by the user. The time of data transmission to the ADF transmitter is synchronized with Moscow winter time (or UTC, Greenwich time) with an accuracy of better than ± 0.1 s, and the moment of transmission of a digital message to the ADF transmitter is synchronized with the PC system time with an accuracy of better than ± 10 ms .

The essence of the proposed solution is that the ADF, under the control of the operator, emits digital messages that are highly accurately linked to Moscow winter time (or UTC, Greenwich time), which, when received and processed on the SC NO SPD or relayed through the GS SDPDs will then be processed at regional data reception and processing centers and transmitted via land lines or other communication lines to the center of the system, where, together with images of the Earth's surface, they will provide more accurate d Forecast. The ability to generate a digital message on any carrier letter allows you to guaranteely transmit information via the APD-KA-RCSPOD radio channel in the presence of a large number of terrestrial interference signals in the frequency range 401-403 MHz.

The claimed technical solution is illustrated by drawings.

Figure 1 - Block diagram explaining the principle of transmission of information from the ADF in the BUT and the GS SPD;

Figure 2 - Block diagram of the ADF;

Figure 3 - Block diagram of the transmitter APD.

Figure 4 - Phase formation with biphasic modulation of the carrier frequency.

Figure 5 - Message Structure in BUT DSPD.

6 (a, b) - the structure of the message in the HS DSS.

Satellite data acquisition and transmission systems (see Fig. 1) include low-orbit spacecraft spacecraft (Meteor-3M, Sterkh and others, where m is an integer ≥1), geostationary spacecraft (Electro-L , “MSG” and others, where p is an integer ≥1), data transmission equipment (ADF, where n is an integer ≥1), regional data reception and processing centers (RKCPOD, where k is an integer ≥3) currently time posted in years Dolgoprudny, Novosibirsk and Khabarovsk and the center of the SSPD system located in Moscow in the State Institution "Research Center" Planet ".

The data transmission equipment includes the following elements: a directional antenna 1, for transmitting a signal to a GS SPD satellite, which can be made in a collapsible version, a small directional antenna 2, for transmitting a signal to a NO SSPD spacecraft, a GPS or GLONASS or GLONASS / GPS navigation receiver (NAP 3) which constructively can be performed in a single housing together with the receiving antenna or separately from the receiving antenna and connected to the external receiving antenna with a coaxial cable, PC 4, transmitter 5, monitor 6, keyboard 7, mouse 8 and uninterruptible power supply th power 9. The composition of PC includes software that controls operation of the NAP 3 and the transmitter 5 to the COM port or USB, in this case between the PC 4 and NAP 3 and PC 4 and 5 transmitter using a cable converter USB - RS232.

An uninterruptible power supply 9 provides filtering of the input voltage of the network 220 V / 50 Hz and power supply of the elements of the data transmission equipment. In the event of short-term power failure (up to 1 h), uninterruptible power supply 9 supplies power to the ADF elements with an alternating voltage of 220 V / 50 Hz from the batteries included in it using a converter with a sinusoidal output. In the event of a long-term (more than 1 hour) power failure using commonly used software included with the Windows XP or Vista 7 operating system, the uninterruptible power supply automatically turns off the PC 4, transmitter 5, and NAP 3.

The transmitter 5 includes the following elements: a reference oscillator 10, a phase modulator 11, a synthesizer 12, which includes two frequency dividers DCH1 13 and DCH2 15 and a phase comparator 14, a low-pass filter 16, a voltage-controlled oscillator 17, a preliminary power amplifier 18, an amplifier power 19, microcontroller 20.

The transmitter 5 provides the formation of operating frequencies (fc) in the range of 401-403 MHz (a total of 35 letters) from a highly stable signal of the reference oscillator 10 with the required output power level (5 ± 1 W), radiation duration (from 1 to 60 s) and a repetition period from 1 to 180 s. As the reference generator 10 can be used a thermostated high-precision reference generator GK-80TS 1 (manufactured by OJSC "Morion") with a nominal frequency value f _o = 10.1507 MHz. The frequency of the reference oscillator f _o can be adjusted within not less than ± 7.5 × 10 ^-7 (± 7.6 Hz). The reference generator 10 has a short time to establish the frequency from the moment of power supply, namely, for 30 s the nominal value is set within ± 1 × 10 ^-7 (± 1 Hz).

The transmitter 5 generates biphasic modulation of the carrier frequency. The phase of the carrier frequency is formed by a phase modulator 11. The principle of formation is illustrated in FIG. On figa) and 5b) shows a view of the modulating signals + P and -P coming from the microcontroller 20 to the phase modulator 11. The phase modulator 11 scales and summarizes these signals. The resulting signal ± Pms comes from the phase modulator 11 (shown in Fig. 5c) and, under the influence of the ± Pms signal, changes the phase of the frequency fo of the reference oscillator 10 according to the same law. In the same way, the phase of the carrier frequency fc of the transmitter changes.

The ratio of the phase spans of the frequencies fc and fo is calculated by the formula:

Where:

fs - the amplitude of the phase of the carrier frequency fc PRD;

ph - the amplitude of the frequency phase fo of the reference oscillator.

For example, if fc = 401.969 MHz, f _o = 10.1507 MHz, then fs / pho = 39.6001261.

The amplitude of the phase fs of the frequency fc within the specified range from fc ⁺ = + (1.1 ± 0.1) to fs ^- = - (1.1 ± 0.1) radians in peak with respect to the phase of the unmodulated carrier is provided by the corresponding setting of the phase modulator .

Synthesizer 12 of the transmitter 5, works on the principle of digital control of the phase synchronization loop. It includes two frequency dividers DCH1 13 and DCH2 15 and a phase comparator 14. Dividing ratios R of the frequency divider DCH1 13 and N of the frequency divider DCH2 15 are set by the microcontroller 21 according to the signals received from the PC 4. The input of the divider DCH1 13 comes from the output of the reference generator 10 through a phase modulator 11 signal with a frequency fo. This signal, divided by the coefficient R, comes from the output of the divider DC1 13 to one of the inputs of the phase comparator 14. The second input of the phase comparator 14 receives a signal from the output of the divider DC2 15. The input of this divider is connected to the output of the voltage-controlled generator 17. Phase-connected in series a comparator 14, a low-pass filter 16, a voltage-controlled oscillator 17, and DC2 15 form a feedback loop of the phase-locked loop. The frequency of operation of the phase comparator 14 is determined by the frequency of the reference generator 10, divided by the division coefficient R of the divider DCH1 13, and is:

For example, if f _o = 10.1507 MHz, and R = 10, then Fpc = 1.1507 MHz.

In order to carry out phase synchronization of the frequency fc of the generator controlled by voltage 17, the division ratio of the divider DC2 15 should be equal to:

For example, if it is necessary to form a letter of a carrier frequency of 401.968 MHz, and Fpc = 1.1507 MHz, then N = 396.

In this case, the frequency of operation of the voltage-controlled generator 20 will be:

For example, if f _o = 10.1507 MHz, N = 396, R = 10, then fc = 401.967720 MHz.

Thus, the accuracy of forming the letter of the carrier frequency 401.968 MHz will be Δf = 280 Hz (Δf = fc-401.968 MHz)

Since the frequency fo of the reference signal generator 10 is constant, at constant values of the coefficients R and N, the frequency Fpc of the phase comparator 14 is also constant. Accordingly, the voltage at the output of the low-pass filter 16 and, as a consequence, the frequency fc of the generator controlled by voltage 17 are constant. When the value of the division coefficient R of the divider DC1 13 changes, the frequency Fpc of the phase comparator 14 also changes, which causes a change in the output of the low-pass filter 16 voltage, which controls the operation of the generator controlled by voltage 17, and, accordingly, the frequency fc (regardless of the value of the coefficients within the operating frequency range of the generator controlled by voltage 17). The division coefficients R and N are integers, their ratios are fractional numbers. By setting certain values of the coefficients R and N, it is possible to set a number of frequencies of the generator controlled by voltage 17 and, accordingly, the transmitter letter in the range 401-403 MHz (35 in total).

The microcontroller 20 is configured to store data on how many pairs of division coefficients R and N, how many characters of carrier frequencies the transmitter can provide, while maintaining operability and high quality of the output signal. In this case, the qualitative characteristics of the carrier frequencies of the transmitter, determined mainly by its reference oscillator 10 and the phase-locked loop, will have the following meanings:

- no worse than ± 500 Hz accuracy of the initial installation of carrier frequencies;

- no worse than ± 200 Hz for 10 years of operation, long-term frequency instability;

- no more than ± 1 · 10 ^-9 per minute frequency drift for a 15-minute interval of the transmitter operating time at a constant temperature;

- no more than 3 · 10 ^-9 residual frequency deviation;

- no more than 1 · 10 ^-9 for 100 ms of signal transmission, short-term frequency instability;

- no more than ± 1 · 10 ^-7 frequency setting accuracy 30 s after switching on;

- levels of spurious emissions relative to the level of radiation of an unmodulated carrier (frequencies when measured by a device with a resolution of a bandwidth of 300 Hz) - do not exceed minus 75 dB when tuned to a carrier frequency of ± 40 kHz or more at any value of the message transmission rate (100, 400 and 1200 bps).

To generate the output signal with the required output power, the signal fc is supplied from the generator by a controlled voltage 17 to the preliminary power amplifier 18, amplified and then fed to the power amplifier 19. The output power of the signal at the output of the power amplifier 19 is 5 ± 1 W at a load of 50 Ohms at VSWR no more than 1.3: 1.

ADF works as follows.

At the time of placing the ADF at the facility, two antennas are installed: a unidirectional antenna for transmitting the signal to the SC SCD and the directional antenna for transmitting the signal to the SC SC. A high-frequency cable is connected to the transmitter and to the antenna, which will be used in the future.

A personal computer, a transmitter and a navigation receiver are installed indoors and are connected to an AC network through an uninterruptible power supply. The antenna of the navigation receiver is installed next to the window (at a distance of up to 50 cm from the window). PC is connected to the INTERNET network (if there is such an opportunity). An uninterruptible power supply is turned on, then a personal computer and a navigation receiver. Further, when power is supplied from the uninterruptible power supply and the toggle switch is turned “ON” on the transmitter, the “Standby” mode is set to the on position. In this mode, the entire transmitter circuit is live, the microcontroller is ready to receive and execute commands from an external PC.

When you turn on the PC, its software synchronizes the system time of the PC by the signal of the navigation receiver, and also determines the coordinates of the ADF installation site. When connected to the INTERNET network, the PC receives the ephemeris of low-orbit spacecraft and calculates the visibility zones for the ADF operation point for 3-5 days to send a message when the spacecraft is above the ADF.

The PC operator, when launching the program for generating digital messages, selects the message format for BUT or GS DSSP, sets the period for transmitting the message, dials the transmitted message and issues a command to broadcast it. The message is emitted in the mode set by the operator in the PC program. The structure of the message (telegram) in the BUT DSPD is shown in Fig.5, in the GS DSPD in Fig.6 (a, b). The amount of useful information in one APD telegram in the NSDP is 28 bytes (letters) / 229 bytes (letters) in a “short” / “long” message, respectively. In GS DSSD, the amount of useful information in one ADF telegram is from 1 to 649 bytes (letters) in a message synchronized by transmission time or from 1 to 28 bytes ("letters") in a "storm" message that the operator can transmit at any time time.

To send a new message, the operator stops the transmission of the message, then dials a new message, sets the message transmission mode and issues a command to broadcast the message. All transmitted messages are stored in the PC memory for six months or more.

Thus, the data transmission equipment for satellite data acquisition and transmission systems will provide continuous and long-term transmission of digital messages (telegrams) in volume from 1 to 669 bytes from land-based stationary objects to the center of the data collection system globally around the globe. The ADF provides the formation of messages with high reliability of information transmission, high accuracy of binding of the moment of message transmission and on many letters of the carrier frequency in the band 401-403 MHz, thereby providing a large number of simultaneously serviced ADFs in the data collection and transmission system, both low-orbit and geostationary effects of interference in the APD-KA radio link.

Claims (2)

1. The data transmission equipment of a satellite data acquisition and transmission system consists of a directional antenna, a low-directional antenna, a transmitter whose output is connected to the directional antenna input or a low-directional antenna input, respectively, a GPS navigation receiver, or GLONASS, or GLONASS / GPS, which constructively can be made in a single housing together with a receiving antenna or separately from the receiving antenna, a PC, which includes software that controls the operation of the navigation GPS, or GLONASS, or GLONASS / GPS and transmitter, the first PC I / O is connected to the inputs / outputs of the GPS navigation receiver, or GLONASS, or GLONASS / GPS, the second PC I / O is connected to the transmitter inputs / outputs, uninterruptible power supply connected to the transmitter, PC and the GPS navigation receiver, or GLONASS, or GLONASS / GPS, a monitor, keyboard and mouse are also connected to the PC. 2. The data transmission equipment according to claim 1, characterized in that the transmitter consists of a reference generator, a phase modulator, the first input of which is connected to the output of the reference generator, a synthesizer, consisting of a first frequency divider, a second frequency divider and a phase comparator of the synthesizer, the first the input of the first frequency divider is connected to the output of the phase modulator, the output of the first frequency divider is connected to the first input of the phase synthesizer, the second input of which is connected to the output of the second frequency divider, low-pass filter A frequency signal whose input is connected to the output of the phase comparator of the synthesizer, a voltage-controlled generator, the first input of which is connected to the output of the frequency filter, the second input is connected to the first input of the second frequency divider, a preliminary power amplifier, the input of which is connected to the output of the voltage-controlled generator, amplifier power, the first input of which is connected to the output of the preliminary power amplifier, the output of the power amplifier, which is the output of the transmitter, is connected to the antenna unidirectional or ant not directed microcontroller, a first output connected to the second input of the first frequency divider, the second output coupled to a second input of the second frequency divider, a third output connected to a second input of the power amplifier, the fourth output coupled to a second input of the phase modulator.