RU2152050C1 - Satellite navigation system for detection of object position - Google Patents

Abstract

FIELD: navigation systems using differential correction methods. SUBSTANCE: method involves reception of navigation signal, which is emitted by each of accessed navigation satellites of main or additional orbiting sets, simultaneously by means of antenna-feeder devices of navigation equipment, reference transmitter-receiver and integral monitoring device, which belong to monitoring correction station. Monitoring correction station contains following functional parts: reference receiving-transmitting device, which detects real value of differential corrections and broadcasts information about differential corrections for user's equipment, integral monitoring device, which monitors broadcasting of navigation signals from accessed satellites and differential correction signal, measures precision of transmitted value of differential correction by means of parallel detection of position of monitoring correction station taking into account received differential correction and their subsequent comparison to known coordinates of monitoring correction station. In addition, it achieves control of operation modes of monitoring correction station and its testing using simulator of navigation satellite signals. In addition, monitoring correction station has data recorder, which detects and stores basic parameters of its operations, redundant equipment, which has complete set of monitoring correction station in hot state. EFFECT: possibility of continuous monitoring of navigation fields, generation of information about integrity of navigation data, increased fidelity of detection of object position using redundant number of navigation satellites. 1 dwg

Description

Technical field
The present invention relates to radionavigation systems for determining the location of objects using the differential correction mode.

 The differential mode of navigation definitions uses a set of additional means of control and correction of navigation information of navigation spacecraft (NSC), which, as a result of a special technique for observing a navigation spacecraft (NSC) and subsequent mathematical processing, improves the accuracy of determining the coordinates of consumers of navigation information.

State of the art
Currently known satellite radio navigation system called "Global Positioning System" (GPS) or "Navstar" [Navigation (VSA), 1978, v. 25, N2], which helps to determine the location of any consumer objects equipped with a receiver that is sensitive to the radio navigation signals of the NSC of this system.

The Navstar system contains 18 NCA with 3 NCA in each of the six circular 12-hour orbits. The orbit planes are uniformly offset relative to each other by 60 ^o . The position of each satellite at any given time is precisely known.

 The location of the consumer object (longitude, latitude and altitude) at any point on or near the Earth can be determined based on pseudorange measurements with respect to four satellites located in the radio visibility zone of this object. Sequential pseudorange measurements allow you to determine the speed of a mobile object.

There is also a Global Satellite Radio Navigation System, called GLONASS. The system consists of 24 NCA, which are evenly distributed through 45 ^o in 3 orbital planes of 8 NCA in each plane. In each plane, the spacecraft move in circular orbits with a height of ≈ 20,000 km with a rotation period of ≈ 12 hours [WO 91/11732 from 08.08.99 (G 01 S 5/14 A1)].

Each NKA in the above systems emits a navigation signal (NS), which is a multicomponent phase-shifted radio signal. The transmitted navigation signal contains the following main information components:
- a navigation message intended for consumers to make navigation determinations and plan navigation sessions, the main content of which includes the ephemeris of the spacecraft — the coordinates and motion parameters of the spacecraft at a fixed point in time, the timeline of a specific spacecraft;
- a pseudo-random sequence designed to measure the propagation delay of the navigation signal from the satellite to the consumer and, accordingly, to determine the range with high accuracy.

 For the GLONASS system, the differences in the navigation signals transmitted by a particular satellite are that each of the navigation signals is shifted in frequency with respect to each other, and a pseudorandom sequence is formed in the same way on all satellite.

 For the Navstar system, the differences in the navigation signals transmitted by a particular satellite are that each of the navigation signals is modulated by an individual pseudorandom sequence, and the carrier frequency of the transmitted messages is the same for all satellite.

In the above satellite navigation systems, it is possible to implement the following modes of location of the navigation information consumer object:
- The standard mode of navigation definitions;
- differential mode of navigation definitions.

 Under the standard mode refers to the mode of navigation definitions of coordinates of consumers of navigation information from observations of at least four spacecraft.

 Under the differential mode refers to the mode of navigation definitions, in which the consumer adjusts the results of the navigation definitions of the standard mode using the information received from the reference station. In this case, errors caused by errors in the ephemeris, departure of the time scale, and delay in the propagation of the signal in the troposphere are corrected. In this case, the final error in the location of the consumer object is significantly reduced [Shebshaevich V.S., Balov A.V., Himulin V.I. The development of the differential method of navigational definitions in the satellite radar GLONASS, Radio navigation and time, RIRV, 1992].

 The closest analogue to the invention to clarify the location of the object using differential correction is US Pat. No. 5,621,646 of April 15, 1997.

 The space of differential corrections is formed on the basis of NS from at least 4 GPS satellite systems and a network of reference stations. Each of the reference stations receives a signal from the observed satellite at frequencies L1 and L2. Any of the reference stations, taking the NS of each observed satellite, calculates the pseudorange balance (error), the ionospheric delay of the navigation signal for each satellite, and the mismatch between the satellite’s onboard clock and the reference station’s clock, which is called the differential range correction (DP) between the satellite and the object. The calculated DP, ephemeris data, time corrections, and the grid of ionospheric corrections via communication lines are transmitted to the “master” station for all observed satellite from all reference stations. "Master" station transmits the received information to a geostationary satellite. A geostationary satellite re-emits these parameters to a consumer object, the receivers of which receive information from a geostationary satellite and NS from each observed satellite at a frequency of LI. The consumer object calculates its location based on the received navigation signal and differential corrections received through the geostationary satellite.

 Each reference station includes an antenna and a receiver of a navigation signal from a satellite (GPS), a meteorological parameter sensor, a computer processor, and a data line.

 The antenna and the receiver of the navigation signal of the reference station receive a signal from the satellite and digitally generate information for the main processor that performs actions to smooth out the calculated pseudorange values, generate navigation data, tropospheric corrections for the distribution of the navigation signal, the residual distance between the satellite and the reference station, clock as well as the exact location of the reference station.

 For each observed satellite, the reference station calculates the pseudorange at frequencies L1 and L2, the remainder is formed with a frequency of 1 Hz. This allows you to determine the ionospheric delay and clarify the resulting pseudorange value, which is entered into the residual range determination unit. The receiver of the navigation signal also decrypts the navigation data transmitted by each observed satellite, which is transmitted to the navigation computer, which generates ephemeris information and the difference in the backlog of the onboard clock and the clock of the reference station, and the results are entered into the unit for determining the residual range. Corrections to the definition of pseudorange due to the influence of the troposphere are also introduced there. Information about the location of the reference station is entered into the residual range calculation unit. After the corresponding procedure for processing the received data, the residual range calculation unit generates the residual range between the base station and the satellite for the external interface of the reference station, the coordinates of the location of the reference station and the ionospheric correction for the propagation time of the navigation signal.

 As the communication lines can be used telephone lines, optical and fiber optic lines and other methods of reception and transmission. The communication line terminal is a “master” station, which polls reference stations, generates the received information and transmits it through a geostationary satellite to a consumer object.

 The equipment of the consumer object includes a receiver of corrective messages, a conventional receiver operating at a frequency of L1 NS from the GPS satellite system, a processor and a display. The processor consists of a main processor that uses decoded correction messages, corrected pseudorange, pseudorange, ionospheric and tropospheric corrections entered into the processor memory. In addition, the corrective message receiver and the navigation signal receiver can be combined as a single device for receiving both the corrective message and the navigation signal.

 When a navigation signal is received from each of the NSCs, the receiver generates pseudorange values for the location of the object, as well as the direction of the line of sight between the consumer object and the NSC. The results are entered respectively in the pseudorange calculator, in the tropospheric correction calculator and in the pseudorange correction calculator.

 The correction signals transmitted by the master station are decrypted and transmitted to the ionospheric correction computer, which generates corrections to the propagation time for each of the observed NSCs, which are taken into account by the pseudorange calculator. Given all the corrections, the pseudorange calculator passes its final value to the location calculator of the user object, which is displayed on the display screen.

 However, the system chosen as an analogue does not provide high accuracy and reliability of the location of the consumer object due to the changing geometric factor for the constellation of the observed NSCs and the lack of control of the transmitted differential corrections.

SUMMARY OF THE INVENTION
The invention is aimed at creating a navigation system for determining the location of a consumer object, which allows continuous monitoring of the GLONASS and GPS navigation fields, generating information about the integrity of the navigation data of the GLONASS and GPS satellite radio navigation system, and increasing the reliability of object location due to the use of an excess of spacecraft (simultaneously using NKA GLONASS and GPS), as well as through the introduction of integrated control of the formed differential corrections and methods for monitoring the performance of hardware and software.

 Realized technical results are achieved by the fact that the satellite radio navigation system for determining the location of the object, containing the orbital constellation of navigation spacecraft (NSC), equipment "n" consumers and at least one reference transceiver (OPP) device, which includes antenna-feeder device (AFU), a reference receiver of a navigation signal (NS), as well as a radio beacon, an additional orbital constellation of the spacecraft, an integrated control device (IR) and a recorder for data, and the device’s OPP includes a switchboard, a control and monitoring unit and series-connected weather control unit, a differential correction driver (DP) and a DP encoder, the AFU output being connected through a switch to the input of a DP reference receiver, the output of which is connected to the first input of the control and monitoring unit, the outputs of which are connected respectively to the control inputs of the AFU, the switch, the reference receiver DP and the encoder DP, the output of which is connected to the input of the beacon, and the device K is made in the form of series-connected first AFU and receiver DP, series-connected second AFU, switch and control receiver NS and series-connected unit for processing navigation parameters (NP), unit for accuracy control DP, unit for monitoring data integrity, control unit and simulator NS, the other output of the data integrity unit is connected to the corresponding input of the control unit through the control unit of the simulation parameters, as well as the external communication interface, the outputs of which are connected respectively with the corresponding inputs of the control unit and the data integrity control unit, the outputs of the receiver DP and the control receiver NS connected to the corresponding inputs of the processing unit NP, the other output of which is connected to the corresponding input of the data integrity control unit, the input of the simulator is connected to the control input of the switch and to the corresponding the input of the control and monitoring unit of the device’s OPP, the output of the NS simulator is connected to the corresponding inputs of the switch and the switch of the device’s OPP, and one of the outputs The data integrity control is connected to the corresponding input of the DP shaper, in addition, the data logger inputs are connected to the corresponding outputs of the control and monitoring unit and the DP shaper of the device and the corresponding output of the data integrity control block.

The reference receiver and the control receiver of differential corrections can be performed according to known schemes (for example, [Proc. GPS-95, Palmsprings, CA, US, Sept. 12-15, 1995, pp. 835-844; Riley S., Howard V. , Aardoom E., Daly P., Silverstrim P. A combined GPS / GLONASS High Precision Receiver for space applications.]
The claimed system operates as follows.

List of drawings
FIG. 1 is a structural diagram of a navigation system for determining the location of an object.

The system includes
1 - orbital constellation of navigation spacecraft 1 (HKA1)
2 - additional orbital constellation of navigation spacecraft 2, (NKA2)
3 - consumer equipment, which includes:
4 - navigation equipment
5 - antenna feeder device (AFU)
6 - receiver differential corrections (DP)
7 - decoder DP
8 - input device DP
9 - reference transceiver (OPP), which includes:
10 - AFU
11 - reference receiver of navigation signals (NS)
12 - shaper DP
13 - control unit of meteorological data (MD)
14 - DP encoder
15 - control and monitoring unit
16 - switch
17 - beacon
18 - integrated control device (IR), which includes:
19 - the first AFU
20 - receiver DP
21 - second AFU
22 - control receiver NS
23 - block processing navigation parameters (NP)
24 - switch
25 - block accuracy control DP
26 - block integrity control data (CD)
27 - control unit
28 - simulator signals NKA
29 - control unit simulation parameters (IP)
30 - external communications interface
31 - data logger
32 - control and correction station (KKS)
33 - redundant equipment
Information confirming the possibility of carrying out the invention.

 The possibility of carrying out the invention is confirmed below by the following description of the operation of a satellite radio navigation system for determining the location of an object. The navigation signal emitted by each of the main or additional orbital constellations observed by the spacecraft is received simultaneously by the AFU of the navigation equipment 4, as well as the AFU 10 of the OPP device 9 and the AFU 19 and 21 of the IR device 18 that are part of the KKS 32 (Fig. 1).

Control and correction station (KKS) 32 is functionally divided into components, the main purpose of which is as follows:
- reference transceiver device (OPP) 9, which determines the true value of the differential corrections and transmits through the beacon 17 information on the differential corrections for consumer equipment 3;
- an integral control device (IR) 18, which controls the passage through the air of the NS of the observed spacecraft and the differential correction signal, checks the accuracy of the transmitted DP value by solving the location problem of KKS 32 in parallel, taking into account the received DP and then comparing it with the known coordinates of KKS 32, in addition, manages the operating modes of KKS 32 and conducts its testing using a simulator of signals NKA 28. The device IK 18 performs a connecting function with external terminals for transmitting and receiving from them official and technological information;
- data logger 31 - registers and stores the basic parameters of the control-correcting station 32;
- backup equipment 33 - reserves a full set of control and correction station 32 in the "hot"state;
The above components of the control and correction station 32 interact with each other as follows.

 The navigation signal is received by the AFU 10 of the reference transceiver 9 and then, in analog form, through the switch 16 is fed to the reference receiver HC 11, where it is formed to a form convenient for analog-to-digital conversion and subsequent extraction of the navigation information embedded in the signal.

 Then, the navigation parameters about the spacecraft are digitally transmitted to the shaper DP 12, where after solving the navigation problem, the numerical value of the differential correction is calculated.

 The numerical values of the differential corrections are translated into the encoder DP 14, which converts the received information to a form convenient for transmission by a beacon 17.

 The control and monitoring unit 15, which is part of the OPP 9, performs the functions of monitoring and controlling the operating modes of its functional units, namely, AFU 10, switch 16, the reference receiver NS 11 and the encoder DP 14 in terms of checking their performance.

 The control unit MD 13 measures the parameters of the external environment (temperature, pressure, wind speed and direction, humidity) and, processing them according to a special technique, introduces an additional tropospheric correction into the shaper DP 12.

 The IR device 18 has two reception channels. One of the channels receives the navigation signal from the satellite, the construction of the receiving part of this channel repeats the construction of the supporting receiving part of the reference transceiver and the receiving part of the equipment of the consumer object and consists of series-connected AFU 21, switch 24 and the control receiver of navigation signals 22. Results measurements made on this channel, in terms of ephemeris data and range measurements are transmitted to the processing unit of the navigation parameters 23, which, based on the received The primary information determines the coordinates of KKS 32 as a result of solving the navigation equations. The processing unit of the navigation parameters 23 is performed according to known schemes and operating algorithms [for example, application WO 91/11732 from 08.08.89 (G 01 S 5/14 A1)].

 Another channel of the IR device 18 receives information transmitted by the beacon 17 OPP 9 about the numerical values of the differential corrections. In other words, the signal of the beacon 17 is received by the AFU 19, then it is transmitted to the DP receiver 20, where the analog signal is converted to digital and put into the processing unit for navigation parameters 23, which solves the navigation problem of positioning taking into account differential corrections. Further, the obtained results are transmitted to the integrity control unit of the navigation data 26. The concept of integrity when using the satellite radio navigation system as the only (main) navigation tool is the ability of the navigation system to exclude incorrect satellite information, and therefore the specific values of differential corrections from subsequent processing before how an error in the output parameters exceeds a predetermined threshold [Report of RTCA Special Committee - 159 on Minimum Aviation System Performance Standarts (MASPS) for Global Positioning]. In other words, this is the state of the radio navigation parameters determined by the signals from the satellite and the transmissions transmitted to the consumer object, which degrades the accuracy of determining the coordinates and time by the consumer object to a value that exceeds a predetermined error threshold for the location of the consumer object (for example, a signal from the satellite a distorted signal structure that does not allow KKS 32 to enter synchronism with the satellite; the presence in the navigation message of the satellite indicates a ban on the use of information from this satellite, as well as a shift in the B belts (BSW), frequency drift of the reference satellite generator; descent of the satellite from orbit; incorrect ephemeris information, etc.).

(1,а)
b) в навигационные параметры (псевдодальность):
R_о = R_выч - R_изм (1,б)
где

вектор координат ККС 32, вычисленный по транслируемым координатам НКА и измеренным псевдодальностям до не менее 4 НКА;

эталонные координаты ККС 32;
R_изм - измеренная ККС 32 псевдодальность для одного и того же НКА;
R_выч - псевдодальность, вычисленная на ККС 32 по транслируемым координатам НКА и эталонным координатам ККС 32.Thus, the data integrity control unit 26 extracts from the navigation message of the processing unit of the navigation parameters 23 information about the health of the spacecraft, or can receive similar or other kind of information through the external communication interface 30. In addition, this block ensures the continuity of tracking of all observed spacecraft orbital groups 1, 2 (GLONASS and GPS), which generates a message to the shaper DP 12 for the consumer object. Further, taking into account the accuracy assessment of the DP, the data integrity control unit 26 generates a message about the normal operation of the KKS 32 or about the operating parameters of the KKS 32 beyond the limits of permissible errors. This message is addressed to the control unit 27. The accuracy control unit of the differential corrections 25, based on the calculated location in the processing unit NP 23, the obtained value of the differential corrections and the exact location of the IR device 18, calculates the error between the true location value of the IR device 18 and the resulting navigation solution determination by NCA taking into account the adopted DP, which should not exceed the specified value. The procedure for conducting accuracy control, omitting unnecessary details, is as follows. After measuring the navigation parameters in the OPP 9, it calculates corrective corrections to the rectangular geometric coordinates of the consumer or to the navigation parameters. Relations for calculating corrections has the form (1):
a) in the coordinates of the consumer:

(1, a)
b) in navigation parameters (pseudorange):
R _о = R _subt - R _ISM (1, b)
Where

KKS 32 coordinate vector calculated from the broadcast coordinates of the satellite and measured pseudorange up to at least 4 satellite;

KKS 32 reference coordinates;
R _ISM - measured KKS 32 pseudorange for the same NKA;
R _subt is the pseudorange calculated on KKS 32 using the broadcast coordinates of the satellite and the reference coordinates of KKS 32.

(2,а)
R_ик = R_изм - R_о (2,б)
где

вектор координат устройства интегрального контроля 18 с учетом принятых ДП (устройство ИК 18 пространственно совмещено с опорным приемо-передающим устройством 9;

R_изм, R_о - см. выражение (1,а, б).The integral control device 18 solves the inverse problem, which follows from the relation (2):

(2, a)
R _IR = R _ISM - R _o (2, b)
Where

the coordinate vector of the integral control device 18, taking into account the received DP (IR device 18 is spatially aligned with the reference transceiver 9;

R _ISM , R _o - see the expression (1, a, b).

(3)
где

- ошибка в определении вектора измеренных координат устройства ИК 18 с учетом дифференциальных поправок.The accuracy control function of DP 25 is reduced to calculating the following relationships (3):

(3)
Where

- an error in determining the vector of the measured coordinates of the device IR 18, taking into account differential corrections.

 The results are transmitted to the data integrity control unit 26, where the operation of checking for exceeding the specified error threshold ε in determining the coordinates takes place.

The control unit 27 performs the control functions of the KKS 32, which include the following:
- the introduction of KKS 32 in working condition;
- monitoring the state of the equipment of individual nodes and blocks;
- switching the backup set of equipment in the event of failure of individual nodes and blocks, as well as in the case of exceeding the specified error threshold ε obtained from the data integrity control unit 26;
- management of the exchange of information through the external communications interface 30, etc.

 The external communication interface 30 performs a connecting role with external sources of messages (for example, the exchange of information with other KKS; receiving, transmitting messages about failures of the spacecraft; receiving messages about special modes of operation of the KKS).

 To check the operability of the control and corrective station 32, the navigation signal simulator 28 is included in the IK 18 device, which generates an NS from the satellite, whose signals through the switch 16 of the OPP 9 and the switch 24 of the integral control device 18 are fed into the corresponding receivers 11 and 22. The control of the switch 24 is directly carries out the control unit 27, and the switch 16 - the control and monitoring unit 15. Thus, using the signals of the simulator 28, KKS 32 conducts an "imaginary" duty cycle, that is, according to well-known NS formed DP after which the integrity of the data is monitored, from where a message is generated on the numerical value of the obtained positioning errors, which is transmitted to the control unit of the simulation parameters 29, where the initial error of the location of the KKS 32, which is incorporated in the formation of the NS NC, is compared with the received error, and a message is generated about output or within the specified range of the obtained positioning value of KKS 32. This message is transmitted to the control unit 27, which decides on the further mode of operation Ota CCR 32.

 Simulation control is carried out cyclically during regular operation of the control and correction station 32.

 In order to archive the main operating parameters in the KKS 32, a data recorder 31 is included in the reference transceiver 9, which is connected to the functional blocks 15, 12 and 26.

 Consumer equipment 3 includes navigation equipment 4 and AFU 5 functional units connected in series, DP 6 receiver, DP 7 decoder and DP 8 input device. Navigation equipment 4 in the context of this invention is a device that solves the problem of determining the location of an object in normal mode ( which was determined above) and which is a structural channel for receiving the navigation signal of the satellite navigation system of the integrated monitoring device KKS 32. The signal about differential corrections is received by the AFU 5 and then processed receiver DP 6. The signal of the receiver DP 6 transmits the received message to the decoder DP 7, where the received message is processed in a form convenient for input into the navigation equipment 4. The input device DP 8 is a matching device that can have a different design and configuration depending on execution of navigation equipment 4.

 For specialists in this field and other areas when reading this description will be clear other possible modifications of this invention. Such modifications may include other structural features known in the art. The above-described variant of the system does not exhaust all their diversity, which can be implemented in accordance with the following claims.

Claims (1)

 A satellite radio navigation system for determining the position of an object, containing an orbital constellation of navigation spacecraft (NSC), equipment of n consumers and at least one reference transceiver (OPP) device, which includes an antenna-feeder device (AFU), a reference receiver of the navigation signal (NS), as well as a radio beacon, characterized in that it introduces an additional orbital constellation of the spacecraft, an integrated control device (IR) and a data logger, and as part of the OPP device in the commutator, the control and monitoring unit and the meteorological data control unit connected in series, the differential correction driver (DP) and the DP encoder are connected, and the AFU output is connected through the switch to the input of the DP reference receiver, the output of which is connected to the first input of the control and control unit through the DP shaper, the outputs of which are connected respectively to the control inputs of the AFU, switch, DP receiver and DP encoder, the output of which is connected to the input of the beacon, and the IR device is made in the form of series-connected the first AFU and the receiver DP, serially connected to the second AFU, the switch and the control receiver of the NS and the serially connected unit for processing navigation parameters (NP), the accuracy control unit DP, the data integrity control unit, the control unit and the NS simulator, and the other output of the integrity control unit data is connected to the corresponding input of the control unit through the control unit of the simulation parameters, as well as the external communication interface, the outputs of which are connected respectively with the corresponding inputs control unit and data integrity control unit, the outputs of the receiver DP and the control receiver NS connected to the corresponding inputs of the processing unit NP, another output of which is connected to the corresponding input of the data integrity control unit, the input of the simulator is connected to the control input of the switch and the corresponding input of the control unit and device OPP control, the output of the NS simulator is connected to the corresponding inputs of the switch and the device OPP switch, and one of the outputs of the data integrity control unit is Inonii a corresponding input BRANCH shaper further inputs data logger are connected to respective outputs of a control unit and control and driver DP CPE device and the corresponding output of the block check data integrity.