RU2184381C1 - Radio navigation system - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: system has terrestrial measuring stations receiving navigation signals from navigation satellites and transmitting navigation parameters via corresponding communication channels to a processing center, N, where N≥1, peripheral processing stations connected to the processing center via a common access communication channel, M sets of user navigation devices connected to each of the peripheral processing stations through narrow bandwidth communication channels. EFFECT: higher flexibility in fitting source radio navigation parameters to requirements of end users. 2 dwg

Description

 The invention relates to radio engineering, in particular to radio navigation systems for determining the location of objects using the differential correction mode.

 Currently known satellite radio navigation system (SRNS) under the name "Global Positioning System (GPS) or" Navstar "(Navigation (USA), 1978, v. 25, N 2), which helps to determine the location of any consumer objects. There is also a Global The satellite RNS, called GLONASS (WO 91/11732), they have high basic operational characteristics and satisfy the navigation requirements of a wide range of users. However, when using SRNS there are at least two problems.

 The first problem is that for a whole series of navigation tasks the standard accuracy of the ARNS is not enough and to improve it you have to use special modes of positioning (for the accepted classification, see, for example, “Global satellite radio navigation system GLONASS”, edited by V. Kharisov V. N., Moscow, IPPR, 1997, and “Russian Radio Navigation Plan. The main directions of development of radio navigation systems and tools, Moscow, 1993, Interdepartmental Commission“ Internal Navigation ”). Methods for organizing such modes are known. They suggest the installation of either a control and correction station (CCS) in the center of the local working area, or a base station (BS) at the coordination point, followed by the determination of the differential corrections or coordinates of the BS, respectively, and their transmission via communication channels to end users.

 However, in practice it is difficult to combine separate local navigation systems into one wide-area navigation system: the appearance of several simultaneously operating KKS (or BS) requires their selection in communication channels. The difference in the algorithms of operation of sets of consumer equipment (CAP) leads to the need to include ionospheric corrections in the general differential corrections for some consumers and exclude them for others. When choosing a communication channel, you have to choose the maximum traffic from the calculation of servicing the most critical consumer, although most users would have arranged a significantly lower load on the communication channel. In addition, for a mobile consumer, as he moves, it is necessary to organize a switch between separate local zones, which according to the existing concept is assigned to the consumer’s equipment. This significantly complicates the CAP and increases its cost, requiring the addition of a single standard for the communication channel. All this does not allow the use of the existing KAP fleet, since it requires both its refinement and installation of complex and expensive communication channels at users' facilities. Because of the above difficulties, only separate departmental subsystems of high-precision navigation are created, as a rule, for solving specific problems within the same local zone and for a limited range of users, and the number of users of single existing wide-area systems is still insignificant.

 In general, it can be argued that one of the problems with the use of existing SRNSs is the impossibility of creating a unified, accessible high-precision navigation system due to the technical difficulties of combining local zones of high-precision navigation within one system at reasonable costs for its creation.

 Another problem is the fundamental difference between real-time location methods and post-processing, where the navigation parameters collected in real time are archived and can then be used at any time at the user's discretion. The latter requires the creation of a bank of navigation parameters, as a rule, to solve one specific problem. Therefore, the use of post-processing in unified systems today is not provided.

 In the general case, methods for solving navigation problems can vary significantly. Nevertheless, they can be combined and at a limited cost create a unified navigation and information system to solve various navigation problems. As a result of the achievements of the used information technologies, an additional advantage of the proposed system will be its simple scalability, accessibility and ease of adaptation to changing individual requirements of end users.

 The invention is aimed at creating such a complex of equipment that would improve the accuracy of positioning and the reliability of navigation parameters transmitted to the consumer, as well as expand the service area. This is achieved due to the fact that the satellite radio navigation system for determining the location of objects contains ground-based measuring points that receive signals from navigation satellites and transmit navigation parameters via the corresponding communication channel to the processing center. The processing center receives navigation parameters, calculates and accumulates an array of basic navigation parameters, archives them and issues navigation parameters at the request of the consumer. The system also contains N, where N≥1, peripheral processing points connected via a shared communication channel to the processing center. Each peripheral processing point serves to convert information from the base array into the navigation parameters required by a particular consumer in a given format and to form an information-logical protocol for their transmission at the request of the consumer. To each peripheral processing point, through the corresponding narrow-band communication channels, M, where M≥1, sets of consumer equipment is connected.

In FIG. 1 is a functional diagram of a satellite radio navigation system for determining the location of objects, which shows:
1 - ground measuring points;
2 - communication channels;
3 - processing center;
4 - communication channel of general access;
5 - N, where N≥1, peripheral processing points;
6 - narrowband communication channels;
7 - M, where M≥1, sets of consumer equipment.

 In FIG. 2 is a navigation service algorithm explaining the operation of a system in accordance with the invention.

 The possibility of carrying out the invention is confirmed by the following description of the operation of the satellite radio navigation system for determining the location of the object. The navigation signals emitted by the respective navigation satellites (not shown) are received by the corresponding ground measuring points (NPCs) 1. All available navigation information is contained in the primary radio navigation parameters, namely, measurements of the quasidality, pseudophase and carrier frequency of satellite signals, as well as in navigation parameters obtained based on their processing. This information is enough to solve any navigation problem. Under ground measuring points 1 are also meant control and correction stations (KKS) in the center of the local working area and base stations (BS) at the points of coordination.

 To create a field of primary radio navigation parameters (RPN), all available NPCs 1 are connected by communication channels 2 to processing center 3. In processing center 3, navigation parameters are received, the array of basic navigation parameters is calculated and accumulated, and archived, i.e. according to well-known algorithms, preliminary processing of primary RNP is performed (calculation of differential corrections for each satellite, determining the location of coordination points, monitoring the operation of the SRNS, etc.) In order to increase the reliability of preliminary processing, its results can be compared with similar information obtained directly from one or several NPCs 1. In the processing center 3, ionospheric and tropospheric components of the SRNS error are also distinguished to ensure the maximum accuracy of error correction in the corresponding M kit (s) 7 consumer equipment.

Thus, in processing center 3, based on primary RNP, at least the following basic set of parameters is determined:
- differential corrections with propagation errors included, coordinates of objects coordination points;
- ionospheric and tropospheric delays in the propagation of satellite signals according to available NPCs, SCS and BS;
- data of current monitoring.

 Together with the primary RNP and the binding of all data to time (for example, UTC), the listed parameters form a basic array of corrective information, which is archived in processing center 3 until it is used.

 The main objective of the proposed system is to adapt the basic source navigation parameters to the requirements of each end user and to deliver these navigation parameters to him. The key issues here are as follows.

 The navigation support procedure for the consumer in the most general formulation provides for the solution of an arbitrarily selected navigation task on the type of CAP 7 available to the consumer. For this, it is necessary to provide CAP 7 with the initial navigation parameters in the required format and in the required time sequence. Under CAP 7 in this invention is understood both the navigation equipment of the consumer and the equipment for the post-processing of navigation information, as well as equipment for other navigation definitions of the consumer, for example, equipment for collecting statistical data on ionospheric errors, etc. When working in a single system of an unlimited number of heterogeneous consumers, there is a problem with the transmission of navigation parameters: the bandwidth requirements of the communication channel turn out to be excessively high, which makes its implementation economically unjustified, and building a unified navigation system is impossible.

 On the other hand, any known method of navigational definitions requires initial information of a limited volume. Calculations show that for navigation definitions with a frequency of 1 Hz, on average, it is enough for a consumer to transmit 1.0 ... 1.4 Kbps of information. Such traffic is provided by almost any service narrow-band communication channel, including the communication channel with a mobile object (for example, the dispatch service of the ground transportation control or air traffic control, etc.). However, to use such a channel in the system, it is necessary to convert information from the base array (obtained above in processing center 3) into the navigation parameters needed by a specific user, in a strictly defined format, and, in addition, additionally form an information-logical protocol for their transmission. In the proposed system, these functions perform the corresponding of N peripheral processing points (PPO) 5. The logic of the software 5 is as follows.

 Each PPO 5 serves a strictly defined circle of end users, united by functional, territorial or any other principle. For example, it can be geodetic users having a common coordination point (i.e., a common BS), aircraft located in the coverage area of one local space station, users working in post-processing mode, etc. Upon request from KAP 7 (for example, one or more of M) based on a priori information (type of navigation definitions held by the user, type of KAP 7 used by him, his rough location, etc.) PPO 5 sets up the entire transmission and reception path with the center processing 3 for the issuance to the consumer of ready-made information from the list available in the processing center 3 and (or) raw navigation parameters. In the latter case, the processing of these navigation parameters is carried out directly at the software 5. The processing algorithm can be selected from among those known for solving typical problems or a priori set by the user by personal request. The block diagram of the software 5 itself is determined by the characteristics of the serviced group of end users and the required computing power: in the general case, it may contain several intermediate processing levels. After establishing a connection with the processing center 3, each software 5 in real time receives from the processing center 3 the ordered basic information and then adapts it to the form specified in the request of the served consumer. After that, from the software 5 information on the narrowband communication channel 6 is transmitted to the corresponding KAP 7 of the end user. If necessary, for example, when the user (mobile object) leaves the coverage area of one narrow-band communication channel 6, its navigation service can be transferred to another software 5 and another narrow-band communication channel 6.

 The implementation of the functions of the processing center 3 and peripheral processing points 5 can be carried out, for example, on the basis of standard computers integrated into a local network (see, for example, K. Aiden et al. "PC Hardware", edition 2, BHV - St. Petersburg, 1998, Ch. 16.).

In the proposed system, the following requirements are imposed on communication channels. The transmission channel of 2 measurements from each NPC 1 to the processing center 3 can be one-way with a throughput of about 6 Kbaud. The block of transmitted information with 20 visible GPS and GLONASS satellites will contain as much as possible:
- pseudorange [20cdx2sl.h32r = 1280 (bit / s)],
- pseudophases [20cdx2sl.h32r = 1280 (bit / s)],
- differential corrections [20kAh2sl.kh32r = 1280 (bit / s)] or coordinates of the base station [4h2sl.kh32r. = 256 (bps)],
- distribution corrections [20cdx2sl.x32r = 1280 (bit / s)],
- time reference to the GPS and GLONASS time scale [4sl.kh32r. = 128 (bit / s)],
i.e., with a total amount of information of not more than 5248 (bit / s). Such a data stream can provide, for example, telephone communication channels, radio channels, etc.

 The most serious requirements are made to the communication channel of the general access 4 of the processing center 3 with the software 5. The channel should provide two-way communication, accessibility at an arbitrary point in a large region (including in its remote areas, for example, in the Far North), ease of connection, not have restrictions on the number of simultaneously served subscribers, the ability to select (program) the received information and bandwidth Ability is not worse than 6 Kbaud for each subscriber. The listed requirements are fully satisfied by the existing global information network "Internet". Connecting to it via satellite channels with ~ 1 traffic (Mbps) allows you to remove the bandwidth limit altogether and use a single peripheral processing point in the system.

 For narrow-band communication channels 6 PPO 5 with KAPs 7 there is only one requirement: to ensure the transfer of additional 1.0 ... 1.5 (Kbaud) information. Almost any communication channel, for example, a telephone communication channel, a wire communication channel, a radio communication channel, etc., meets this requirement. As a rule, mobile objects are equipped with multichannel communication systems with independent subchannels. Therefore, it is advisable to allocate one of the free subchannels for the transfer of additional navigation parameters.

 The above-described operation of the proposed system is also illustrated by the navigation service algorithm of the consumer in the system, a possible version of which is presented in figure 2, which also reflects some service commands that allow more clearly present the operation of the system in question.

 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 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, which is made without a restrictive part, because in this form it more clearly reflects the essence of the invention.

Claims (1)

 A satellite radio navigation system for determining the location of objects containing ground-based measuring stations receiving radio navigation signals from navigation satellites, determining primary radio navigation parameters from them, namely quasidality, pseudophase and carrier frequencies of satellite signals, as well as navigation parameters obtained from their processing, and transmitting these navigation parameters via the corresponding communication channel to the processing center, where the navigation parameters are received, their comparison, determination on their basis of an array of basic navigation parameters in the form of differential corrections with included errors in signal propagation, coordinates of coordinate points of objects, ionospheric and tropospheric errors in signal propagation, current monitoring data and primary radio navigation parameters, their accumulation, archiving and output at the request of the consumer, characterized in that N peripheral processing points are introduced, where N≥1 connected through a two-way communication channel of general access, equipped with the ability to select the information to be received for a particular consumer, with a processing center and each one for converting information from the base array of navigation parameters based on a priori information from the consumer to the navigation parameters required by a specific consumer in a given format and for generating an information-logical protocol for their transmission upon request consumer, and to each peripheral processing point through the corresponding narrow-band communication channels connected M, where M≥1, to mplektov consumer equipment.

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