Cellular location system, a compensating delay of signals received in the radio positioning

 

The invention relates to electrical engineering and can be used in communication systems to compensate for the delays of the received signals at the receivers location. The technical result consists in increasing the accuracy of the positioning. The system determines the time of detection of the received radio signal at the radio location and takes into account the previously stored signal delay associated with one or more receiving cascades relevant radio location, and the time of detection, with the aim of determining the times of arrival of the received radio signals. 4 C. and 24 C.p. f-crystals, 4 Il.

The invention generally relates to communication systems and, more specifically, to compensate for delays of signals received in the radio positioning.

The development of commercial radio and, in particular, the rapid development of cellular radiotelephone systems changed the nature of communication between people. According to one study, about 80% of people who buy blocks of mobile communication and anonymousi service, do it to improve personal safety. Apparently, many of the Phnom car breakdown or emergency, when you want to immediately call a doctor or the police. In such circumstances, it is desirable that the communication system can determine the location of a mobile unit, especially when the subscriber himself doesn't know exactly where. In addition, it is expected that the FCC (Federal communications Commission) 'll stipulate that network operators to send the data about the location of the caller at risk in an emergency.

There are many methods of generating location information of the mobile unit. One of the systems of the positioning provides that the mobile unit has the ability to self-assess your location and send a message with your coordinates when calling the emergency number. This feature can be implemented, for example, providing a mobile unit receiver Global satellite system positioning (GPS, GSPC), which receives the location information from the satellite network of the GSPC. Then the mobile unit will be able to transfer this information to the system, which, in turn, will forward it in an emergency. However, this would require significantly modify existing mobile units with the purpose and base stations.

On the other hand, to determine the location of the mobile unit can be used base stations that transmit signals to the mobile units and receive signals from them. For transmitting location information of the mobile unit can be used various techniques, including those based on measuring the signal attenuation of the mobile unit, angle of arrival and the difference between the times of arrival (ETA) of the signal of the mobile unit at different base stations. Cm. for example , article Luis A. Stilp (Louis A. Stilp), entitled "Time difference of Arrival Technology for Locating both narrowband Cellular Signals", SPIE, volume 2602, pp. 134-144. For locating mobile units in wireless systems, you can use another system, which is an optional system, which is valid regardless of the radio system. The system includes its own base station for identifying the mobile unit. Although the system can use various circuit elements (e.g., antenna) together with the communication system, however, the processing of the signals it produces separately. This approach has no advantage, for example, as a rational solution to the problem of issuing the location information mobilarena mobile unit, should be detected, some algorithms determine the location based on the time of arrival of the received signal reported at least three radios positioning in three or more places. By processing times of arrival, the location of a mobile unit that should be detected, is determined by well-known algorithm positioning with circles of constant radius. This algorithm is based on the intersection of at least three circles, the radii of which correspond to the arrival times reported by the receivers location.

However, actually, the radio positioning determines the time of detection, corresponding to the time when the received signal of the mobile unit that should be detected, is detected, and not the time when the received signal does come on the radio location. The time of detection is the time when the received signal out of the detector of the receiver, after passing through various foster cascades RF and if applications that add delay to the detection of the received signal. In ideal conditions, according to the system location would contribute to the delay of the same magnitude, it could easily be deleted by the system algorithm of the positioning. However, due to tolerances on the circuit elements, it would be wrong to assume that different receivers location have equal delay.

For example, some types of filters FC are very different from each other according to the group delay is the time required for propagation of energy through the filter even when nominally identical circuit elements. From experimental data it follows that the ceramic filters, which are widely used in receivers because of their reasonable cost and performance, show deviation of a group delay of approximately100 NS from the mean. As a result, various uncertainties and tolerances affect the positioning, which leads to inaccuracy and ambiguity of the location. Even if all other conditions of the system operation, location perfect, 100-nanosecond uncertainty of the time of arrival of the received signal makes positioning uncertainty, which is about 30 m (about 100 feet). In Fig.1 the uncertainty of the location, due to resposibility, the respective times of arrival at the first receiver location and at a second receiver location, which are used to determine the location of the mobile unit. Each radio location is represented by two concentric circles, the radii of which represent the uncertainty in100 NS. Thus, the radio positioning, which include circuit elements such as filters FC having the maximum distribution of tolerance condition error and ambiguity in the definition of the system the location of the mobile unit in the order of several hundred feet. It is therefore necessary to provide a system location, which would compensate for the uncertainty in the location due to tolerances on the circuit elements of the radio positioning.

The present invention solves this problem, implemented in the system location, which improves the accuracy of positioning by measuring and pre-save delay signal associated with the radio definition mestopolojenie the present invention, includes a detector that detects the signal of the mobile unit received by the corresponding receiver location, and a timer that determines the time of detection associated with the received signal. The processor determines the time of arrival of the received radio signal based on the time of detection and the measured or calculated signal delay previously stored in the storage element. The detector cell block handles the arrival times obtained from the set of radio location, to detect a mobile unit.

According to disclosed in more detail the characteristics of the present invention, the delay signal includes a measured or calculated group delay associated with the filter, which is part of one of the foster cascades, and measured or calculated delay of the transmission line associated with the transmission line, part of the radio. Preferably, the arrival time was determined based on the difference between the delay signal and the time of detection. However, as shown in an example implementation variant, the arrival time can be determined on the basis of time deposits.

Other characteristics and advantages of the present invention are evident from the following description of a preferred variant implementation, presented in conjunction with the attached drawings, in which: Fig.1 is a graph showing the inaccuracy of the location associated with the location of the mobile unit using the conventional radio location; Fig. 2 is a diagram of the global positioning system, which implements the present invention; Fig.3 - scheme of the radio positioning used in the system shown in Fig.2; Fig. 4 is a chart of the message delay, which is used to send the signal delay associated with the receiver shown in Fig.3.

In Fig. 2 shows the system 1 location, which implements the present invention. According to a variant example of implementation, the system 1 location is an optional location system similar to that disclosed in U.S. patent 5327144 issued by Stipu and others , entitled "System for detecting the location of cell phones" ("Cellular Telephone Location System"), the contents of which included in this is lituano not only in the advanced systems determine the location, but in nedoponimaniya systems positioning. System 1 location includes three radios 2, 3, 4 location, which are not necessarily in the same place where are the base stations of cellular radio system, in which the served mobile subscriber units. In addition, the figure presents the base station 5 cellular system that supports communication in cell 6, in particular, to a mobile unit 7, the location of which must be determined in accordance with the present invention. Radios 2, 3 and 4 location track mobile treatment unit 7 to the system. When the mobile unit 7 carries out emergency treatment system 1 of the positioning handles the arrival times of signals received from the mobile unit 7 receivers 2, 3 and 4 determine the location to determine the location of the mobile unit 7 using, for example, the well-known algorithm positioning with circles of constant radius. As shown in an example variant implementation, the processing times of arrival of received from radios 2, 3, 4 definitions it is currently owned by the 7 in the center of 9 emergency care.

According to the present invention, the measured or calculated signal delay associated with one or more receiving cascades radios 2, 3, 4 location, pre-stored or at each radio location, or at the Central station 8. When determining the location of the mobile unit 7, the detector 15 the location of the mobile unit, which is part of the Central station 8, processes the arrival times obtained on the basis of the delay signal on the corresponding radio positioning. Therefore, unlike conventional methods, in determining the location in accordance with the present invention take into account the previously saved deviation of the delay signal associated with the radio location. Measuring and pre-storing the signal delay, the location system, which implements the invention can accurately detect the location of the mobile unit 7 without any uncertainty associated with the tolerances on circuit elements radios 2, 3, 4 positioning.

In Fig.3 presents a diagram of the radio receiver 10 opredelit in itself the totality of foster cascades, each of which can make a measurable signal delay in detection of the received signal. According to the figure, a receiving antenna 11 receives a signal transmitted from the mobile unit 7 (Fig.2), and submits it to the cascade 14 RF through the transmission line 12. It is well known that the transmission line 12 connecting the antenna 11 with a cascade of 14 HF, delays the received signal by feeding it with the delay of the transmission line. Cascade 14 HF, which provides pre-amplification and selectivity of the receiver delivers the received signal to the cascade 16 inverter to convert with decreasing frequency, carried out by a commonly known method. Cascade 16 inverter generates an if signal in line 18, which is transmitted to the information contained in the received signal. To issue the if signal cascade 16 FC uses the filter 20 of the inverter, for example, a ceramic filter, which introduces additional group delay. Therefore, the delay of the received signal includes a delay line transmission and group delay. The if signal is fed to a detector 22 that detects the received signal at the time of detection. Radios positioning time is measured detection using a well-known logical is, corresponding to the time when the received radio signal is detected on one of the reception cascades.

According to the present invention, the delay line transmission and group delay are measured or calculated according to well known methods, which determine the delay of the received signal associated with the cascades HF. For example, the signal delay for each of the receivers 2, 3, 4 location can be measured during manufacture or during installation of the technical staff, which uses dual-channel oscilloscope or automated means. The delay of the transmission line can be measured or calculated based on the line length and velocity factor. The delay value signal, which is typically in the nanosecond range, the pre-stored in the element 28 storage delay signal, preferably in the form of binary-coded decimal numbers. Item 28 storage may represent a previously saved binary-coded decimal number through the DIP switch or via binary bytes or words stored in non-volatile storage element.

As shown in the example of variants 30, preset the signal delay from the time of detection to determine the actual time of arrival of the received signal. With this arrangement, the radio receiver 10 of the positioning indicates the time of arrival at the Central station 8 for joint processing with the times of arrival coming from other similar radios positioning. The radio positioning reports the arrival time by means of the transmitter 32, which communicates with the Central controller through either a wired or wireless transmission medium.

According to one embodiments of the invention, the radio receiver 10 location sends the delayed signal to the Central station 8 in conjunction with the time of detection. For example, according to one of embodiments a radio receiver 10 location transmits to the Central station 8 encoded digital message delay, which has two fields. As is shown in Fig.4, in the first field 34 transmit the signal delay on the receiver. According to another variant implementation, the second field 36 may include a Delta value corresponding to the difference AET for subtracting the delayed signal from the time of detection to determine the time of arrival. Radio 10 location can transmit the message delay to the Central station 8 from time to time or periodically to provide updated location information. With this arrangement, the Central station 8, which can save a sent message delay, subtracts the preset delay signal from the periodically updated times of detection for continuous determination of the arrival times.

Let us return to Fig. 2. According to another aspect of the present invention, the Central station 8 includes a Central element 38 storage for storing the signal delay associated with each of the radio positioning. According to this aspect of the invention, the signal delay is determined during installation of the system using the reference signal, in a known location, for example, runatload from all of the receivers location. Determining the arrival times from the source of the reference signal, it is possible to measure the signal delay associated with each of the radio positioning. Signal delay on radios 2, 3 and 4 determine the location s of the detector 15 the location of the mobile unit, which also takes the time of detection of the transmitted radio 2, 3, 4 location, during the processing times of the parish, with the aim of finding the mobile unit 7.

From the above description it is obvious that the present invention provides increased accuracy in location determination algorithms that use the arrival times for the mobile detection units, by removing variance associated with the tolerances of circuit elements used in the radio location. Thus, the present invention can be used in any communication systems, additional or nedoponimaniya to accurately find the location of the mobile unit.

Although in the description of the invention provide links only to the preferred implementation, for specialists in the art it is obvious that allow various modifications not beyond the scope of the invention.

Claims

1. System for determining the location of a mobile unit that uses multiple radios location remote from the Central station containing a detector in which Amy on the appropriate radio positioning, the timer at each receiver location, which determines the time of detection associated with the received signal, characterized in that it contains a storage device in each of the receivers location, in the above-mentioned storage device stores the delay value signal associated with the one or more receiving cascades corresponding receiver location, the processor in each of the receivers determine location, which determines the time of arrival of the received radio signal based on the time of detection and the delay values in the corresponding receiver location, and the detector of the mobile unit in the Central station, which handles times of parishes on many radio positioning, to determine the location of the mobile unit.

2. The system under item 1, characterized in that the delay of the signal corresponds to a group delay associated with the filter, which is part of one of the foster cascades.

3. The system under item 1, characterized in that the signal delay corresponds to the delay of the transmission line.

4. The system under item 1, characterized in that the arrival time ecaudata fact, what time are determined based on the time of detection and Delta values obtained from the difference between the signal delay relative to the nominal values.

6. The system under item 1, characterized in that the signal delay is determined by using a reference signal, in a known location, runatload from all receivers positioning.

7. The system under item 1, characterized in that the signal delay corresponds to the delay line transmission and group delay associated with the filter that is part of one of the receiving stages of each radio location.

8. Radio location that contains one or more receiving circuits, which process the received radio signal, a detector that measures the time of detection, corresponding to the time when the received radio signal is detected by one of the receiving circuits, characterized in that it contains a storage device in which are pre-save signal delay associated with one or more receiving cascades, and a transmitter for transmitting information about the time of arrival, received on osnovana cascades contains filter moreover, the delay of the signal corresponds to a group delay associated with the filter.

10. Radio on p. 8, characterized in that the receiver includes a transmission line, and the signal delay corresponds to the delay of the transmission line associated with the transmission line.

11. Radio on p. 8, characterized in that it further comprises myCitadel intended for calculating the difference between the delay signal and the time of detection, and information about time of arrival and the transmitter transmits the thus obtained information about the time of arrival.

12. Radio under item 8, wherein the transmitter transmits the time information of the parish, which includes the delay of the signal and the time of detection.

13. Radio on p. 8, characterized in that the information about the time of arrival based on the Delta value obtained from the difference between the signal delay relative to the nominal values.

14. Radio under item 8, wherein the transmitter transmits the time information coming periodically.

15. Radio on p. 8, characterized in that the signal delay corresponds to the delay line transmission and group delay associated with the filter that is part of one ol the I mobile unit, namely, that carry out the detection of the received signal of the mobile unit multiple radios location, and determine the time of detection associated with the received signal in each of the multiple radios positioning, characterized in that the implement retrieving pre-stored values of the signal delay associated with one or more receiving cascades one of the radio positioning, and pre-stored delay value of the signal stored in the receiver location, determine the receiver's location, the time of arrival of the received radio signal based on the time of detection at the receiver location and the pre-stored delay value signal and perform processing in arrival times to determine the location of the mobile unit.

17. The method according to p. 16, characterized in that it further perform processing times of arrival, coming from a variety of radios location to determine the location of the mobile unit.

18. The method according to p. 16, characterized in that sideridou.

19. The method according to p. 16, characterized in that the signal delay corresponds to the delay of the transmission line associated with the transmission line, which is part of the receiver.

20. The method according to p. 16, wherein the arrival time based on the difference between the delay signal and the time of detection.

21. The method according to p. 16, characterized in that the time of arrival based on time of detection and the Delta value obtained from the difference between the signal delay relative to the nominal values.

22. Cellular location system to search for a mobile unit comprising a plurality of radio location, each of which includes one or more receiving circuits, which process the received radio signal, and a detector, which measures the time of detection, corresponding to the time when the received radio signal is detected on one of the receiving circuits, characterized in that it contains the Central station, which includes a storage device which stores the signal delay associated with each of the radio positioning and block determine the location of the mobile unit, which processes the information about arrival times,rich block, moreover, the arrival times receive based on the values of time of detection received from the radio positioning and values of the delay signal.

23. Cellular location system according to p. 22, characterized in that the signal delay previously retain the Central station.

24. Cellular location system according to p. 22, wherein the delay value of the signal passed from the radio positioning.

25. Cellular location system according to p. 22, characterized in that each of the receivers includes a filter, and delay of the signal correspond to the group delays associated with filters radios.

26. Cellular location system according to p. 22, characterized in that each of the receivers includes a transmission line, and the delay corresponds to the delay of the transmission line associated with the radios.

27. Cellular location system according to p. 22, characterized in that the arrival times receive on the basis of the difference between the delay signal and the time of detection on the radio.

28. Cellular location system according to p. 22, featuring the nom location equidistant from all radios positioning.

 

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