JP3365319B2 - Differential correction location system and method for mobile communication networks - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention is directed to a system for locating a unit in a communications network and a method for performing such locating. . More specifically, the present invention provides
It is directed to systems and methods for performing location in mobile communication networks, such as cellular telephones or personal communication systems (PCS) networks.

[0002]

2. Description of Related Art The ever-increasing popularity of mobile communication devices, such as cellular telephones, etc., has accompanied with it the demand for increased reliability and functionality of these devices. Bring As users increasingly rely on wireless telephone networks, and as these phones are ubiquitous in everyday life, the networks are becoming more convenient for the ever-expanding range of demand. It must be achievable.

F by the US Federal Communications Commission (FCC)
One such demand, published in June 1996 as CC Docket Number 94-102, requires future wireless services to provide a site selection mechanism for its mobile units. This mechanism is primarily an emergency 9 familiar to most wireless telephone users.
11 (E-911) service for use in providing complementary emergency call service capabilities. The ability to automatically determine the location of a caller to provide emergency services to the caller is convenient for some communication systems used to make emergency calls. This is because time is of paramount importance in an emergency situation, and further, the caller may not know his or her location, and incorrect or inaccurate may give location. Alternatively, it may be invalidated during the call.

In the case of wireline networks, such localization is a relatively simple matter of correlating the caller's telephone number with a list of numbers and corresponding addresses. However, in the case of wireless E-911 services, even the mobility that makes mobile phones very useful precludes simple inspection techniques for location. Thus, "dynamic" localization methods must be used in mobile networks.

Many location systems are based on the Global Positioning System (GPS) implemented by the US Department of Defense (DoD). GPS is precisely timed and controlled so that between 5 and 8 satellites, wireless contact with any point on Earth at a given time is theoretical in line of sight. It is a group of 24 active artificial satellites that orbit the earth in a defined orbit. Each satellite broadcasts a unique encoded signal that can be captured by a suitably equipped GPS receiver or "rover". The rover's timing is synchronized with that of the satellite and equipped with short-lived data that allows it to accurately calculate the position of each of the satellites at any given time. It receives signals from three or more satellites and calculates its distance from each based on the transit times of its respective signal. Each of the distances defines a sphere centered on its respective satellite, and the intersection of all spheres is the rover's actual position.

[0006]

However, the GPS
The position selection of is not perfect. Various sources of error can cause the detected position of the rover to differ significantly from its actual position, and their coupling effect can prevent the system from encountering a minimum 125 meter accuracy requirement set by the FCC. In civilian utility, the biggest source of error is by far said to be "selective effectiveness," and in order to deny the highly accurate positioning capability of the adversary party, the civilian use of GPS artificial satellite signals. It is the result of DoD that slowly reduces the completeness of the part. Other errors are due to natural conditions such as ionospheric and tropospheric conditions, and to satellite clock and orbit errors, receiver noise and multiple propagation effects, stems from artificial sources.

[0007] Multi-propagation refers to a source (eg,
It occurs when moving from a GPS satellite) to a destination (eg, a rover). If a line-of-sight line exists between the satellite and the rover, as shown in FIG. 12, direct reception will occur via the true signal TS. However,
The signal produces a reflected wave that travels a longer distance reflected from an object in that region, and thus is delayed in relation to the original signal and appears as a separate signal from the rover. The multiple reflection signal has two sources: the signal S.
From static elements resulting from reflections from static objects such as mountains, buildings, etc., such as R, and dynamic elements resulting from reflections from moving objects such as vehicles, such as signal DR. Including the element.

13 through 15 show the effect of multiple propagation on the location selection process. FIG. 13 shows an idealized typical topography, for example a city area of several blocks. FIG. 14 shows a GPS distorted by multiple propagation.
The area | region similar to the area | region which appears in the rover of the area | region based on position information is shown. FIG. 15 shows how the position of the rover in the area is falsely detected based on such unreliable information.

Although the detrimental psychosomatic effects of multi-propagation have been shown in connection with GPS location, such problems are of course encountered in many types of communication with rover, for example from base stations. Be done. With the exception of multiple propagation, all of these errors are experienced to the same extent by the receiver in the same general area, and the "differential GPS (D
A technique referred to as "GPS)" takes advantage of this fact to increase the accuracy of location. DGPS uses a reference receiver whose actual position is precisely known in the vicinity of the mobile receiver. The reference receiver calculates its predicted position based on the signals from GPS artificial satellites and compares it to its actual known position to derive a differential correction. Used to enter and modify the position of a rover over an information channel, eg radio, the multi-propagation effect cannot be modified in this way, the multi-propagation effect being significant with small changes in position This is because a change and a particular set of modifications is generally valid only for a given rover at a given position at a given moment in time.

It is possible to incorporate a rover into a mobile telephone unit and provide GPS position information during an E-911 session. However, this method has some drawbacks. For example, GPS receivers are relatively expensive, and the inclusion of such units in cellular phones and the like substantially increases their cost, especially with DGPS capabilities. In addition, the GPS receiver
It is a complex electronic device that consumes a significant amount of power.
One inclusion in mobile phones either reduces the battery life of the phone or requires the use of larger capacity (and consequently larger size) batteries. Thus, the size of the phone must be increased to accommodate its battery and additional GPS circuitry.

Moreover, GPS satellites are relatively weak, which do not penetrate buildings and other dense structures well and require the use of specialized directional antennas.
It provides high frequency (carrier in the 1.2 to 1.6 GHz range) signal. Additionally, DGPS operation requires the use of a universally useless reference receiver. In addition, the first position fix by the GPS receiver is E-after it is turned on (referred to as "cold reading" as opposed to "hot reading" done by the unit operated for one cycle). It can take up to 15 minutes which is clearly unacceptable in a 911 environment. Ultimately, the need for a GPS receiver at each handset means that existing handsets lacking such functionality cannot be used for wireless E-911 positioning.

Some of these problems are solved by a technique called "cell radio location", in which a cellular base station transmits from a mobile unit (typically a reverse voice channel or reverse control). Channel transmission), and angle of arrival (AO
A) Alternatively, the time difference of arrival (TDOA) technique is applied to the transmission to determine the location of the unit. IEEE communication magazine pp. 33-41 (1996 10
As described in "Location Location Using Wireless Communications on Future Highways" by
AOA technology uses highly directional antennas to determine the precise angle at which each base station receives mobile unit transmissions, and the position of the mobile unit is known at the base station's known position. Determined by triangulation. GP
Like S, the complementary TDOA technique measures the relative delay in receiving a mobile transmission at each base station and determines the distance traveled by the transmission to each base station based on its respective delay, Then, the position of the moving unit is determined by cutting.

However, these methods are still susceptible to positioning errors resulting from multiple propagation and other effects. The need to consider such error sources is E-
It is of particular importance in dense urban areas where it cannot be monitored in 911 applications and where users are in close areas and where there are concentrated multiple environments. SUMMARY OF THE INVENTION In view of the above problems of the prior art, it is an object of the present invention to provide a location system for mobile communication networks that enables highly accurate location determination.

Another object of the present invention is to provide a location system for mobile communication networks that is not significantly affected by multiple propagation effects. Yet another object of the present invention is to provide a location system for a mobile communications network that provides accurate location determination independent of errors associated with satellites and the atmosphere.

Yet another object of the present invention is to provide a location system for mobile communication networks that provides accurate location determination and does not require the use of a handset with special functionality.

[0016]

The above objects are achieved by providing a large number of small, exclusively specific purpose, multi-calibration transponders in the coverage area of a base station at known locations. When the rover begins an E-911 session, the base station commands the transponder to generate a response signal. These response signals are received by the base station and the characteristics of the signals from the rover and transponder are provided to the base station controller linked to that base station. The base station controller
The original rover position information is used to derive the coarse position, and the original transponder position information and their known positions are used to derive a correction vector representing the multiple distortions of the transponder signal in the region of the rover. Since the rover will generally experience similar distortion to the transponder in that region, its correction vector can be applied to its coarse rover position to get its true position.

As an alternative, rather than deploying an array of transponders, the multi-distortion effect at multiple sites can be pre-recorded by using a single transmitter and stored by its base station controller. May be. Then, instead of the base station instructing the transponder to emit a response signal, the base station controller derives a correction vector for the position of the rover based on the recorded site data, and corrects that vector for the coarse rover position. Can be used to

Other objects and features of the present invention will become apparent according to the following description. Additional objects and advantages of the present invention will become more readily apparent from the following detailed description of the embodiments according to the accompanying drawings.

[0019]

Detailed Description of the Presently Preferred Embodiment Embodiments Coverage Area 10 of a Mobile Communication System
Is a group of multi-calibration transponders 1 that are pre-placed there in a well-known position as shown in FIG.
Have two. In addition to the transponder 12, the system also includes a number of base stations 14 within communication range of the transponder 12, which are located at precisely known locations and are separated from each other by a relatively long distance, and It includes a base station controller 18 (shown in FIG. 4) that controls transactions between base stations 14.

For example, when rover 16 makes an E-911 call, base stations 14 each receive a signal from rover 16 as indicated by the solid arrow in FIG. Normally, position determination using AOA, TOA or TDOA based on the signal from the rover 16 received by the base station 14 may be corrupted by the multiple effects described above. However, base station 14 also receives signals from transponder 12, and these signals are
Used for position correction to counter such multiple effects, as described in more detail below.

As known in the art, a rover 16 is associated with a given base station 14 that makes outgoing calls and receives incoming calls. Then, as the rover 16 moves, its associated base station 14 changes through a process called "handing off." When the user of the rover 16 makes an E-911 call, the rover 16 uses the E-911 call.
The 911 request is sent to the currently associated base station 14 as shown in step 100 of FIG. The base station 14
Receives the request and begins the process to locate the rover 16. Essentially, the transponder 12 to be used is selected and the rover 1 is selected at step 102.
6 position and send a "wake up call" to these transponders 12 in step 104.

Preferably, the transponder selected is the transponder which is generally in close proximity to the rover 16. The determination of the approximate proximity can be made, for example, by the AOA, TO described above without the benefit of the signal from transponder 12.
Performing a coarse position fix using one or more of A or TDOA, using different relatively low resolution selection techniques, or a rough proximity predetermined around base station 14. It requires a preliminary positioning made by simply defining it as a region. As an alternative, base station 14 may send an awakening call to all transponders within its coverage area. Moreover, the base station 14 need not send a wake up call to all targeted transponders 12 themselves, and
Alternatively, the request may be sent to another nearby base station 14 to make some awakening calls.

Each transponder 12 includes an antenna connection network 20 connected to a receiver 22 for receiving an awakening signal from the base station 14, a transmitter 24 for transmitting a response signal to the base station 14 as described below, and A controller 26 is included which controls the operation of the receiver 22 and transmitter 24 and controls the application of power thereto from a power supply 28 as shown in FIG. Preferably, the power supply is a rechargeable battery trickle-charged by AC utility mains or solar cells for self-sufficient operation, wind power, etc., eg nickel-hydrogen methyl (Ni-MeH).
Alternatively, it is driven by a lithium-ion unit.

Normally, transponder 12 is in an energy-saving sleep mode in which only those circuits required to recognize an awake call and activate the rest of transponder 12 are active. The sleep mode is active only by the receiver 22 and the controller 26 (antenna connection network 20 is generally a passive network). So that the receiver 22 can receive the wake-up signal and its controller 26 responsive to receiving the wake-up signal directs the power supply 28 to increase the energy consumption of the transmitter 24 and to send the response signal. The transmitter 24 may be driven. Alternatively, the sleep mode may be a slotted sleep mode in which the receiver 22 is normally off and only the controller 26 (or alternatively only the power up timer 30) is active. In this case, the controller 2
6 commands power supply 28 to periodically power up receiver 22 and transmitter 24 to check for wake-up signals, or power-up timer 30 also controls other transponder components.

In any case, when the transponder 12 receives the awakening call, the transponder 12 reaches sufficient power in step 106 of FIG.
A response signal is sent to all base stations 14 in the area at 08, and then returns to its sleep mode at step 110. Each transponder 12 incorporates a unique identification code in its response signal in order to identify the transponder response signals from each other and to correlate them with their respective units.

The response signal may be at a predetermined frequency and power level, or it may be at a frequency and power level encoded in the wakeup signal. The power level may be the power level used by a mobile unit such as the rover 16 in normal communication. As an alternative, in order to ensure that the transponder signal is received by some base stations 14 so that reliable position determination can be made, its power is generally below the range allowed. May also be at a higher level, that is, a level used only for such emergency communications.

Along these lines, the base station 14 associated with the rover 16 also directs the rover to transmit at a higher than normal power level, as shown in step 116 of FIG. 16 sends the command. The resulting high power transfer from the rover 16 in step 118 ensures that the signal is also received by some base stations 14. This is a special concern in low power CDMA cellular and PCS communication systems that are designed to provide a single base station channel to a particular rover and thus cannot guarantee connectivity with multiple base stations. .

The reception of the high power transfer command from the base station 14 to the rover 16 in step 116 and the rover's response in step 118 receives the rover's E-911 request in step 110 and the calculation of the rover's home position in step 112. It may be performed at some point between (and described in more detail below). In addition, base station 14 is controlled by base station controller 18 to rover E-9 to minimize disruption to other communication sessions.
11 Base station 14 may request a high power response from rover 16 only when it is informed that the number of other base stations 14 receiving 11 requests was too few for accurate position determination. unknown. This function is such that each base station 14 responds to the base station controller 18 with an E-911 call request directed to that base station or some other base station 14 as shown in step 120 of FIG. May be performed if sending a -911 call report. Therefore, if the base station controller 18
If the base station controller determines that the number of base stations 14 within the range of the rover's normal power level transmission is too small, the base station controller causes the base station 14 to make a high power response at step 124. Base station 1 associated with rover 16 in step 122 to command the rover
4 can be notified.

As an alternative to the above technique, the rover 16 may be designed to always send E-911 requests at high power levels. This simplifies system operation. However, it does so at the expense of disrupting the communication of other rover 16 in the area.
In any case, high power transmission on the end of the rover, of course, requires the use of a modified rover.

Similarly, the base station 14 uses the step 1 of FIG.
The responses are first received at step 126 of FIG. 8 so that they normally request a normal power level response from the transponders 12 at 04, and these transponders 12 provide a response that can be received at step 128. The second high power response request is issued only to the transponder 12 that was not present. If the base station 14 still does not receive a response from a particular transponder 12, the base station 14 indicates that the transponder 12 is not working well.
Message may be sent (the operation of the transponder 12 may also be checked by periodic status polling by the base station 14). Alternatively, the high power transfer may be authorized by the emergency operator or other authority. In any case, the transponder 12
It may remain awake for a predetermined period or until those transponders receive a sleep command from the base station 14. As a result, they are step 126.
Receive high power transmission command at and step 128
Can make an appropriate response in.

Each base station 14 receives not only the original E-911 request from the rover 16 in step 100 of FIG. 3 or the subsequent high power response in step 118 of FIG. 6, but also step 108 of FIG. 3 or step of FIG. 128
The response signals from the transponder 12 are received within the communication range in FIG.
Transponder 12 and rover 1 in step 112 of
It is used to derive coarse position information for each of the six. For example, each of the base stations 14 may receive an angle of reception of each response signal (for an AOA system), an absolute time of reception of each response signal (for a TOA system), or (TDO).
Determining the relative time of receipt of each response signal (for the A system) using techniques known in the art,
The information may then be provided to the base station controller 18 in step 114.

Since each of the base stations 14 can obtain precisely synchronized timing information via the GPS system, the TDOA technique was used in the preferred embodiment and added to the AOA for added accuracy. It However, other technologies or combinations of technologies may be used instead. Moreover, cellular system information such as the sector in which the rover 16 is currently located, handoff information, etc. can be used in the position determination process. Further, in areas where a user's roundabout route is compelled, a geographic database may be used to provide inferred AOA information for use in the process.

Ultimately, any geolocation technique used can be increased with the GPS receiver at the rover 16. The receiver will position GP in the normal way.
The S information may be derived and relayed to that base station 14. However, in order to minimize the size of the rover and reduce its power consumption and cost, the receiver is
The GPS data it receives may be simply short-lived and relayed to the base station 14 or another centralized facility for processing. Of course, this method
It has the drawback of requiring the use of a modified rover 16.

The base station controller 18 uses the signal information corresponding to the rover 16 to calculate the coarse position for the rover 16. Then, the base station controller 18
Calculates the coarse position for each transponder using the signal information corresponding to each of the response transponders 12. These coarse positions are compared to the known actual position of transponder 12 to obtain the multiple distortion vectors. The coarse position calculated for the rover 16 is therefore modified according to the multiple distortion vector,
To determine the actual position of, apart from the multiple effects. And
This actual location is passed to the wireline network for transmission to the appropriate authorities during the E-911 session.

In other words, the base station controller 18
Assume that in-situ data has been received from several base stations 14 as shown in step 130 of FIG. It then calculates the coarse rover position P _RC = (x _RC , y _RC ) in steps 132 and 134, and based on the data from the base station 14, the n coarse transponder positions P _T1c = (x _T1c , y _T1c). ), P _T2c = (x
_T2c , y _T2c ), ..., P _Tnc = (x _Tnc , y _Tnc )
To calculate. Therefore, the actual known position of the transponder is _T1a = ( _xT1a , _yT1a ), P _T2a = ( _xT2a ,
y _T2a ), ..., P _Tna = (x _Tna , y _Tna ), the vector bar δ _n representing the transposition of each transponder i due to multiple distortions is calculated in step 136 according to the following equation (1). Is determined in.

[0036]

[Equation 1]

If there are more base stations 14 than need to respond to the coarse position fix for the rover 16 and transponder 12, proper averaging, weighting or other modification techniques may be used to obtain the coarse position. , Or additional base station data is used to correct the geometric dilution of precision, thereby increasing the accuracy of the process.

The absolute value │δ _n │ of each distortion vector bar δ _n , which represents the distance by which the coarse transponder position P _Tic of transponder i is displaced from the actual transponder position P _Tia, is transferred to step 138 using the equation (2). Calculated.

[0039]

[Equation 2]

Since the transponder 12 whose predicted position is closest to the coarse position of the rover 16 is likely to represent the distortion experienced by the rover 16, the relative weight w _Ti depending on the proximity of the corresponding transponder 12 to the rover 16 is
The multi-distortion vector bar δ _n for that rover is obtained from the equation (3) at step 140 and is calculated by the equation (4) as the sum of the weighted transponder distortion vectors at step 142.

[0041]

[Equation 3]

[0042]

[Equation 4]

The actual position P _Ra is then calculated in step 144 from the equation in equation (5).

[0044]

[Equation 5]

Here, the bar δ _R is given by the following equation (6).

[0046]

[Equation 6]

Then, the actual position P _Ra is E-911.
It may be given to the emergency authorities at the beginning of the calling session. Alternatively, the processing may be done while the E-911 call is being initiated and its location will be transmitted later. The above process has been discussed in the context of regularly spaced arrays of transponders 12. However, it is clear that the relative position of the transponders 12 is not critical as long as their actual position is known precisely and they can communicate with the base station 14. Thus, the present invention is equally applicable to the irregular distribution of transponders, ie the fact that it is particularly useful in dense urban areas where regular positioning of the device is not possible.

Furthermore, it is not even necessary to use multiple transponders, and the transponder is E-
It need not be available at the time the 911 call is made. This possibility is explained in the context of the second preferred embodiment of the invention shown in FIG. This embodiment obviates the multiple transponders used in the first embodiment and instead relies on a pre-collected database of position correction information. Prior to use of the system to perform any position determination, a transmitter similar to transmitter 24 of transponder 12 used in the previous embodiments, for example, by physically transferring it into the vehicle. It is placed in a number of positions. At each position, the position of the transmitter is accurately determined. This may be done in a number of ways to successfully avoid the effects of multiple distortions. For example, the position fix may extend over a longer period for increased accuracy, or the position of the transmitter may be known using known techniques such as dead reckoning or surveying techniques, e.g. May be extrapolated from one of

Once the position of the transmitter is known, a signal is transmitted from the transmitter to the base station 14 and original position data corresponding to the received signal is transmitted from each base station 14 to the base station controller 18. To be done. This process is repeated at many different positions n. Then, the coarse position P _Tic
Are derived from the aggregate data for a given position i, and, as described above, the corresponding known actual position P _Tia to derive the transmitter distortion vector bar δ _n for the given position i. Can be compared with. The transmitter distortion vectors δ _{T1 to} δ _Tn are then stored in the memory of the base station controller 18.

When the system is required to provide positioning points for E-911 calls, base station 14
As in the first embodiment, step 100 of FIG.
At, the E-911 request is received from the rover 16. Then, instead of selecting a transponder for awakening, it generates in-situ data in step 146 of FIG. 10 and sends an E-911 request to the base station controller 18
And provide the base station controller 18 with in-situ information for the rover 16 in step 148. The base station controller 18 receives the original position information from the initial base station 14 as well as the other base stations 14 in step 150 of FIG. 11, and in step 152 the rover 16 (as indicated by the coarse position P _Rc ). Transmitter distortion vector for pre-recorded position, approximately near
The bar δ _n is regenerated, the relative absolute value w _Ti of the transponder strain vector δ _n is calculated in step 138, and the multiple strain vector δ _R is obtained in step 140 as described above. The rover coarse position P _Rc is then modified at step 142 to obtain the actual rover position P _ra passed to the wireline network.

This embodiment has the benefit of avoiding the deployment of a potentially expensive array of multiple calibration transponders. However, it can only cancel the effects of static multi-distortion and cannot handle dynamic strain elements. While the present invention has been fully described in connection with its more preferred embodiments with reference to the accompanying drawings, it should be understood that various changes and modifications will be apparent to those skilled in the art. Such variations and modifications should be understood to be within the scope of the invention as defined by the appended claims.

[Brief description of drawings]

FIG. 1 is a diagram showing a first more preferred embodiment of the present invention in the following topography.

FIG. 2 shows a transponder according to a first embodiment providing a response signal to a base station for the differential correction of the position of the rover.

FIG. 3 shows a transaction between a rover, a base station and a transponder in the first embodiment when determining the position of the rover during an E-911 call.

FIG. 4 is a diagram showing operations of a base station, a transponder, and a base station controller for determining a position of a rover under a multi-distortion state in the first embodiment.

FIG. 5 is a block diagram of a multi-calibration transponder according to the first embodiment.

FIG. 6 is a diagram illustrating a modification of the first embodiment in which a rover selectively provides high power transmission.

FIG. 7 shows a variation of the first embodiment when the rover's initial E-911 request is not received by enough base stations and the transponder retransmits at a high power level.

FIG. 8 shows a variation of the first embodiment when the transponder's response is not received by the base station and the transponder retransmits at a high power level.

FIG. 9 is a diagram showing processing of the base station controller in the first embodiment when correcting the position of the rover with respect to multiple distortion.

FIG. 10 shows a transaction when determining the position of a rover according to the second more preferred embodiment of the present invention.

FIG. 11 is a diagram showing a base station controller correction process in the second embodiment.

FIG. 12 shows a typical path of multiple propagation between a GPS satellite and a rover.

FIG. 13 is a diagram showing rover position distortion due to multiple effects in urban topography.

FIG. 14 is a diagram showing rover position distortion due to multiple effects in urban topography.

FIG. 15 is a diagram showing rover position distortion due to multiple effects in urban topography.

[Explanation of symbols]

12 ... Transponder, 14 ... Base station, 16 ... Rover,
18 ... Base station controller, 22 ... Transmitter, 24 ... Receiver, 26 ... Controller, 28 ... Power supply.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 102 H04Q ^7/ 00-7/38

Claims (5)

(57) [Claims] 1. A mobile communication device emitting a communication signal, a plurality of transmitters each emitting a calibration signal, characteristics of the communication signal and the calibration signal received by the communication signal and the calibration signal, respectively. A plurality of first stations that respectively generate reception information based on the received information, and the corrected position of the mobile communication device by receiving the reception information from the first station and using the reception information corresponding to the transmitter. And a second station for determining the corrected position and providing the corrected position to the communication network.
And at least one of the first stations further comprises:
Send a wake-up command to at least one of the transmitters
And at least one of the transmitters transmits the wake-up signal.
Periodic from sleep mode to active mode to check
, And when the awakening signal is present,
A transponder adapted to emit a calibration signal
Therefore, the power consumption rate of the sleep mode is the same as that of the active mode.
Positioning system lower than power consumption rate . 2. A mobile communication device emitting a communication signal, a plurality of transmitters each emitting a calibration signal, respectively receiving said communication signal and said calibration signal, and
Characteristics of the communication signal and the calibration signal received there
A plurality of first stations that respectively generate reception information based on
And receives the received information from the first station, and sends the received information to the transmitter.
By using the corresponding received information, the mobile communication
The correction position of the communication device and communicate the correction position
Positioning system comprising a second station providing to a network
And at least one of the transmitters has a calibration signal
Higher than the standard communication power level of the mobile communication device
Positioning system adapted to emit at power level
Mu . 3. At least one of said first stations
To the at least one of the transmitters
Command to send its calibration signal to the higher power level.
And at least one of the transmitters transmits the calibration signal.
A transformer that emits at the level specified by the above command
The position determination system according to claim 2 , wherein the position determination system is a ponder . 4. A system for transmitting a communication signal from a mobile communication device.
And emitting a calibration signal from each of the plurality of transmitters, the communication signal and the calibration signal at each of the plurality of first stations.
Signal as it is received and received there
And generating a received information based on the characteristics of the calibration signal.
The mobile communication using the step and the reception information corresponding to the transmitter.
Determining the modified position of the device, and providing the modified position to the communication network.
A method for determining the position of a mobile communication device according to claim 1 , wherein at least one of the first stations
Steps to send a wakeup command to at least one of them
And at least one of the transmitters from sleep mode.
Check the awakening signal by periodically switching to sex mode
And the number of transmitters of the transmitter when the wake-up signal is present.
The step of issuing a calibration signal from at least one
The sleep mode power consumption rate is the active mode power consumption rate.
Determine the position of mobile communication device lower than power consumption rate
How to do. 5. A system for transmitting a communication signal from a mobile communication device.
And emitting a calibration signal from each of the plurality of transmitters, the communication signal and the calibration signal at each of the plurality of first stations.
Signal as it is received and received there
And generating a received information based on the characteristics of the calibration signal.
The mobile communication using the step and the reception information corresponding to the transmitter.
Determining the modified position of the device, and providing the modified position to the communication network.
A method of determining the position of a mobile communication device, the step of issuing the calibration signal comprising:
At higher power levels than standard communication power levels,
Generate a calibration signal from at least one of the transmitters
For determining the position of a mobile communication device, the method comprising:
Law.