FI114273B - Location of a mobile terminal - Google Patents

Description

114273

Location of a mobile terminal

Field of the Invention

The invention relates generally to determining the location of a mobile terminal in a system where part of the subscriber line is constituted by a radio link between the terminal and the access node.

Technology background

The mobile terminal can be located by a variety of methods. Positioning accuracy varies greatly depending on the application, the environment and the positioning method used. Currently, the accuracy of the positioning range when using a single receiver is from a few tens of meters to several kilometers.

The positioning methods can be divided into three different categories of implementation: network positioning, terminal positioning and hybrid positioning.

Network positioning is based on the physical structure of the radio network or a specific coverage area of the serving cell. One method used for network positioning to locate a mobile station is the triangle measurement method.

Terminal tracking is a method tied to a terminal. A prime example of this is the Global Positioning System (GPS) based on global positioning. The GPS receiver i receives signals from the orbiting satellites and calculates its position using the information contained in the signals. The terminal may be either a GPS receiver. or a mobile station that has an integrated GPS receiver.

:, 25 Hybrid positioning refers to [·. a combination.

Radio signal strength positioning method ... is usually based on a comparison of predicted and measured signal strength.

In such a method, the network design system defines signal strength estimates based on field measurements, signal propagation model and iterative analysis of the parameters used. The values thus obtained are static values which generally do not contain information about the environmental conditions. However, environmental changes may have a significant effect on the strength of the radio signal field. The following are some * «· 35 examples of various environmental changes that affect field strength: 1) slow environmental changes: seasons, construction; 2) 114273 peat changes in the environment: changes in the weather (water, sleet, snow, fog, storm), changes in the immediate vicinity of the radiating antenna (new building components, large vehicles); 3) unpredictable changes in the component forming the radio signal field: failure of the transmitter, transmitter antenna or transmitter cable, water saturation of the antenna and / or cable, corrosion in the terminals, aging of the transmitter unit and contamination or freezing of the antenna shield.

The natural propagation of a radio signal is influenced by a number of factors whose exact mathematical determination is impossible. In practice, the measured field strength 10 at a given distance from the transmitter may be one hundred times less than, for example, a meter from said location. Measured values may change when the field strength is measured again at the same locations over time. In fact, variations in field strength are usually smoothed by describing field strength as an average of 15 areas.

Field strength predictions can be improved by utilizing data from field-based measurement receivers. The problem with known implementations is that the corrections to the predictions are based on the use of static correction factors due to environmental conditions. Implementations based on static estimates do not contain real-time information and • cannot account for sudden weather changes or equipment failure.

i In order to be able to locate the terminal as accurately and reliably as possible, it would be necessary to obtain real-time information on the field strength in the terminal's mobile environment. However, there are currently no real-time implementations of environmental changes.

BRIEF SUMMARY OF THE INVENTION The object of the method and system of the invention is to improve the accuracy and reliability of positioning of a mobile terminal of a radio system. The positioning method used as such can be anything.

* * Λ

The objective is achieved as described in the independent requirements.

In the field system of the radio system, one or more measurement receivers are received at a specific station • · · * · ”receiving a support station transmission signal; The radio system used determines what is the quantity to be measured from the received signal. In GSM (Global System for Mobile Communications) 3 114273, measurement receivers measure, for example, the signal strength of a signal transmitted by nearby base stations. The measurement receivers report their measurement parameters from the signal to the control and calculation center of the measuring receivers at certain predetermined time intervals. In addition, the measurement parameters can be requested from the measurement receiver at any time.

Measurement parameters are utilized in two ways:

First, the measurement parameters are collected over a period of one year, for example, and the data collected is used to optimize the design system itself and / or the static prediction grid generated by the planning system and describing the coverage area of the radio network. In this way, the design system and the forecast values of the static forecasting lattice it produces will become more accurate in the long run.

Second, when locating a mobile terminal, e.g., in a GSM-15 network, the measurement receiver control and calculation center utilizes the aforementioned static prediction grid or part thereof for positioning, but the information contained therein is further refined based on real-time or near real-time measurement parameters received from at least one measurement receiver. The location of the mobile terminal is always known at least on a cell-by-cell basis, so that the system knows the measuring receivers in the vicinity of the terminal and uses the measurement parameters reported by at least the nearest measuring receiver to correct the prediction lattice values. If necessary, measurement parameters can be requested from the measuring receiver in connection with the positioning request.

·. 25 Periodically reported measurement results from the measuring receivers allow the effect of ambient conditions on signal strength to be taken into account in real time, resulting in more reliable and accurate position prediction. The position prediction can be further refined by making a differential correction based on the measurements of at least one measuring receiver 30 and its exact known location. Also, refinement based on long-term measurements of the static forecasting lattice of the design system improved * · Λ. ·· *. Shore forecasting, for example, as the effects of, for example, seasonal variations on signal strength are better known.

«» »• · 4 114273

In one embodiment of the invention, at least a portion of the measuring receivers are mobile measuring receivers that perform measurements at known predetermined locations.

5 List of patterns

The invention will now be described in more detail with reference to the accompanying diagrammatic figures, of which Figure 1 illustrates the system with functional blocks, Figure 2 is an example of positioning measuring receivers in the terrain, Figure 3a illustrates a general structure of the arrangement Figure 4 is a flowchart illustrating a process for compensating for environmental changes; Figure 5 is a flowchart illustrating a location correction information process; Figure 6 is a flowchart illustrating a network status monitoring process: Figure 7 illustrates a calibration of a design system, and | FIG. 8 is a flowchart illustrating a user terminal location process.

Detailed Description of the Invention

1-8, the improvement of the accuracy and reliability of the position prediction of the radio network terminal according to the invention is taken into account in the following, when calculating the location of the terminal taking into account the real-time effects of the environment on the radio signal. The method 30 and the system determine the location of the mobile terminal using: the field network area field ku- ··· in the network planning system. a heavy static prediction lattice, or part thereof, in combination with real-time or near-real-time measurement parameters (e.g., field strength parameters) obtained from measurement receivers located in the radio coverage area.

* ·:. * ·· 35 It should be noted that when referring to a lattice, prediction lattice, field strength lattice, and correction lattice, a lattice the size of a whole country, a single telescope, or a very limited small area such as a measuring receiver. The aforementioned lattices may be two-dimensional or three-dimensional and one or more layers. The application used determines the form in which the lattice and the information it contains is most efficiently and usefully utilized 5.

The static prediction values describing the coverage area of the radio network produced by the design system are not necessarily in the form of a lattice but, for example, as a database, matrix, vector field, table, algorithm or function. In this case, the system calculation unit forms a forecast-10 grid that contains the forecast values produced by the planning system.

The radio signal is also referred to herein as the signal.

By way of example, improving the position prediction of a positioning method based on radio signal strength in a Global System for Mobile Communications (GSM) network is illustrated. Note that the method 15 is not limited to implementation in a GSM network only, but can be implemented in any radio network. The positioning method used may also be any positioning method suitable for the implementation. The system used determines what is the measurable quantity of the system used in the method. The example locates a particular GSM network terminal in response to a service request sent by the terminal. In order to provide the terminal with the most accurate positioning information, the positioning information is corrected taking into account the current environmental conditions. This is possible when, in the terrain, measuring receivers are placed in suitable fixed installation locations; Timers that measure the radio signal strength of nearby base stations and report their measurement parameters and any other necessary information to control and count the measurement receivers of the system.

Figure 1 illustrates the system by means of functional blocks. Here the functionality is divided into four different blocks. In practice, depending on the application, the functions may be located on one or more devices. Annex.

»· ·; .. * A The measuring receivers 100-102 are terminals located at certain installation locations within the coverage area of the radio network. Installation location: A: One or more measuring receivers are placed. The measuring receiver 35 is a suitable GSM terminal, for example, or the measuring feature can be implemented in an existing device in the network, such as a base station.

6 114273

The measurement receiver receives the signal from at least one base station and automatically measures the signal strength at predetermined times and upon request.

When the measurement receiver is a GSM terminal, it reports its measurement parameters over the radio to the system measurement and control center 103. If the base station receiver of the GSM system acts as a measurement receiver, the measurement parameters are transmitted to the calculation center 103 via a fixed connection. Report data is sent automatically, upon request, or both.

The measurement receiver control and counting center 103 includes connection set-up means 104, a control unit 105 and a calculation unit 106, as well as databases for the measurement receiver location information 107 for the lattice lattice 108, the correction lattice 109, and the alarm parameters 110.

The measurement receiver control and calculation center, after its own operations, sends the measurement parameters of the measurement receivers to the location center unit 113, whereby the measurement parameters optimize the databases, settings, functions or behavior related to the location algorithm 116 used for mobile terminal location. In addition to the previous 20, the control and calculation center for the measurement receivers sends the corresponding information to the design system calibration unit 112 for the design system. a system 115 or a radio network coverage forecast thereof produced by it for optimization. The measurement parameters used for calibration are based on long-term measurements. Seasonal variations often cause major '25 changes in the environment: in summer, trees have leaves when the intensity of the field is: - going higher than in times when the trees are leafless. Within the same measuring range, different field strength values are typically obtained in winter, spring, summer and autumn. Using the long-term average of the measurement parameters -! * · ', The static forecasts of the design system are refined. The measurement parameters are stored in the database 111 for optimization, for example, for a period of one year.

A In addition to improving terminal positioning accuracy, the measurement results reported by the measuring receivers are also utilized to monitor network condition. The control unit 105 monitors the measurement results received from the measuring receivers 35 and, if it detects a significant change in the measurement parameters, such as below a certain predetermined field strength threshold, it alerts the alarm center 114.

Figure 2 illustrates an example of locating measuring receivers in the terrain. In the figure, there are two measuring areas, a measuring area 200 and a measuring area 201. The measuring receiver 202 in the measuring area 200 measures the signal strength transmitted by three base stations 203-205 and the measuring receiver 206 in the measuring area 201 measures the signal strength transmitted by the base stations 203, 204 and 207. In the GSM system, the radius of the measuring receiver's detection range can be up to tens of kilometers-10.

Because each measurement receiver listens to the GSM radio channels it detects in its area, at least some of the measurement receivers measure partially the transmission of the same base stations. The accuracy of the measurement parameters in such areas is thus quite reliable. On the other hand, if one of the measuring receivers fails-15, further measurement parameters are obtained from other measuring receivers in its immediate vicinity.

Generally, the automatic measurement duration of radio signals and the time between measurements are determined by the measuring receiver at its location. The time between measurements can be defined as long (several 20 months) or short (½ h, 1 h, 2 h) or even by activating the measurement, for example, following a positioning service request. It is also possible to request measurement parameters from the measuring receiver when needed, for example in the event of a rain or storm.

Depending on the application, the measurement receiver transmits a measurement par - - * 25 meters to the measurement receiver control and counting center at certain predetermined intervals. The length of the slot is individually defined in gold! also for the measuring receiver. In areas where changes in weather conditions can be sudden, the time interval is defined shorter than in regions with more stable weather conditions. The environment determines how often measuring equipment is needed

I I

, ··. 30 to install.

Figure 3a illustrates a method according to the invention:. * i A and the system through five processes. The system may be decentralized or it may be a single system. The required functions are logical functions that can be located on one or more devices.

t »8 114273

Any location method may be used to locate a mobile terminal. One positioning method is described in FI110550.

The processes are first described briefly. Their details will be discussed in more detail below. All of the processes described utilize the measurement parameters received from the measurement receivers. The fifth process relates to the actual location of the terminal. It should be noted that terminal location does not require that all processes be performed before the location of a particular terminal can be determined. The processes are self-10 and have a certain execution time. The execution times of the different processes are unique. Once the process has been completed, it is repeated after a predetermined time and / or upon request.

The first process is related to compensating for environmental changes. Database 301 of the network planning system 300 has a static prediction mode representing the field of the radio network coverage provided by the planning system 15, which is divided into smaller parts called elements. The items include field strength predictions for a specific radio coverage area geographic location. Depending on the system, the static prediction lattice contains, instead of the field strengths, prediction information of another measurable quantity, such as the phase of the radio signal. or energy / bit data. The static prediction lattice is multilayer so that the-. each transmitter has its own level.

When the user's mobile terminal is to be located, either at the user's request or by the operator or the authorities, at least 25 parts of the static prediction lattice elements 303 are updated based on real-time or near-real-time field strengths of measurement receivers 302 stationary in the radio network coverage area. In this example, the updated forecast grid is called the field strength grid. The field strength lattice is interpolated and stored 304. It should be noted: "*: 30 that the static prediction lattice prediction values of the design system do not change with the location of the terminal, but the static prediction lattice prediction values are corrected based on long term measurements in the design system calib. We will return to this below.

The measurement receivers automatically report the measurement parameters to the measurement receiver control and calculation center at certain predetermined intervals. Thus, reporting may not be done while locating a mobile 9114273 terminal. The first process, i.e., updating and interpolating the static forecast lattice, is repeated periodically using the measurement parameters reported by all the measurement receivers in turn. The reporting period of the various measuring receivers may vary.

Another process involves generating position correction information.

The positioning algorithm 305 used in the position determination of the terminal utilizes the real-time field strength data measured by the measuring receiver 302 to compute its own position prediction of that measuring receiver. The result of the calculation 306 is compared with the well-known position information 307 of the measuring receiver 10 and the result is a correction grid 308. It should be noted that the elements of the interpolated field strength grid 304 and the correction grid 308 do not need to be equal; can vary.

! The third process involves monitoring the status of the network 312. In the process, observing the field strength information reported by the measuring receivers ensures that the variation in the radio field strength of the base stations remains within the set limits. The data is sent to the network central monitoring station 314. When the set limit is exceeded, the network control unit alarms.

20 The fourth process relates to the calibration of the design system 313.

. . The planning system and / or the information contained in the prediction grid 301 provided by it

* I

the interpolated field, based on long-term measurements, is updated. by means of the information contained in the intensity lattices at certain predetermined intervals and / or as required.

The fifth process involves locating the mobile terminal 309.

For the mobile terminal, the location forecast is calculated using the location algorithms * *. The radio field strength information detected by the mobile terminal 309 is utilized in the calculation. Alternatively, the necessary information is obtained from the serving base station. The position provided by the positioning algorithm is corrected: 310 by the information contained in the correcting grid 308 described above. Final; position prediction is utilized, for example, in a positioning service or * 1 · Λ !,. * is sent directly to user 311.

FIG. 3b illustrates an embodiment of the invention. Fig. 3b V, '· otherwise corresponds to Fig. 3a but does not use a correction grid. Without the correction made by the correction grid 35, this implementation does not provide as accurate a positioning result as the implementation of Figure 3a. However, real-time or near-real-time measurement results from at least one measuring receiver are utilized in the location calculation, i.e., environmental changes are taken into account in determining the location of the mobile terminal.

The processes can be performed simultaneously or at different times. The order in which Pro-5 processes are executed depends on whether one of the processes requires information from a particular other process.

Due to the processes, the error effects on the positioning accuracy of the environmental changes in the area under consideration can be significantly reduced because the effect of the environmental changes on the radio signal strength can be individually considered in the radio propagation model of each transmitter. The propagation patterns of transmitters in close proximity and at the same frequency within a limited range can be corrected with reasonably good accuracy based on information from one measuring receiver. The more data from multiple measurement receivers, the better the accuracy.

15 The following is a detailed review of the processes used to improve the accuracy and reliability of the position prediction of a radio network terminal. A common factor in the processes is the use of a measurement receiver and utilization of its measurement parameters.

The measurement parameters of the measuring receivers are used to fine-tune the correction lattice of 20 on the other hand the position prediction of the terminal. data with real-time or near-real-time measurement parameters; and, on the other hand, long-term data contained in the static forecasting grid of the design system. Of course, the information contained in the static forecasting lattice of the design system will also be updated whenever necessary, as with changes in the network (new cell, device, antenna, etc.).

; > 'In addition, the measurement parameters of the measuring receivers are utilized: for monitoring network status.

Figure 4 illustrates a process for compensating for environmental changes: a flow chart. For example, environmental changes are those described in the prior art: *: 30.

; Assume that the design system radio network coverage; the field static forecast values are in the form of a forecast table.

Then, in the first step 400, the field strength predictions provided by the design system: Y: lock field shape as a function of the radio field as a function of location are copied from the table at the control and measurement center of the measuring receivers.

Thus, the prediction grid comprises field strength predictions without covering the geographical area. As mentioned above, the area may be a Kool-5 country-wide area or, for example, a city.

Copying is done either automatically at specific time intervals or manually. For example, copying is done every year. Copying is also performed when needed, for example, when a new cell is added, an existing cell is modified, an antenna is added, or the transmit power is changed, or the radio channel is changed. Copying is commonly done when there are changes in the network that may change the field strengths of the radio coverage areas or other quantities measured in the method and system.

At step 401, the control unit 105 of the measurement receiver control and counting center 153 selects, for example, at a predetermined time, the first measuring receiver. Selection may be by region. There are a number of ways to define the area under consideration to best suit each application. In one embodiment, the area may be defined as the whole of Finland, southern Finland, a region of a particular county, city or part of a city. A region may also be defined as a cell or multiple cells. In addition to the area division, it is possible to specify how accurately the units of measurement for that area are selected. For example, all units in the area, every second unit, every third unit, or only in critical locations can be selected.

In step 402, the measurement parameters of the area measuring receiver · are collected and the necessary correction is calculated in the calculating unit 106. The correction shall be made in accordance with the calculation rules of the Control and Calculation Center for Measurement Receivers. A field strength grid is also formed therein; the field strength data corrected for the items is exported, in step 403. If. *. 30 field strength grids are already formed, upgrading existing, ·. van field strength lattice field strength information. The field strength error shape corresponds to the shape of the prediction grid produced by the planning system or based on the prediction data produced by it. Thus, if the predictive power la is two-dimensional, then the field strength lattice is also two-dimensional.

: 35 If measurement parameters are desired from more than one measuring receiver, the above steps are repeated. If the measuring receiver was the last of 404 selectable measuring receivers, the process would restart after a predetermined time 405. Of course, the process can also be started if necessary.

Figure 5 illustrates a process associated with positioning 5 correction information. The idea is to further improve the positioning accuracy of the terminal in addition to the above remedies. Because one or more measurement receivers in the vicinity of the terminal! the exact location is known, location information is utilized in positioning.

In step 500, a measuring receiver is selected. The selection is made by the control and calculation center for the mit-10 receivers. The selection can be made as described above. The measurement parameters are received from the selected measuring receiver.

Generally, selection and data collection in any process can be done automatically or at the request of the system administrator.

The measurement receiver control and calculation center forwards the measurement parameters it has collected in step 501 to the positioning center unit 113, where the position prediction is calculated using the positioning algorithm 116. The positioning center unit returns its calculated position prediction to the control and counting center of the measuring receivers, whose calculating unit 106 compares the actual positioning of the measuring receiver with the result produced by the positioning algorithm. The actual installation location for the gauge receivers is obtained from database 307.

As a result of the comparison, a correction vector is generated in step 503, which represents the error of the actual (installation) and computed (• location). In step 504, a correction grid is formed (or an existing critical grid is updated) by interpolating the differential vectors of the various measuring receivers. The effect of a single measuring receiver on the correction grid is reduced as a function of distance.

Γ The above steps are repeated 505 until the data measured by all the desired measuring receivers 30 is processed. The process is executed. again after a predetermined period of time 506 or as required.

* With the help of the repair grid described above it is possible to do '·; · 'Differential correction modified for position forecast.

: A: Known as differential correction is mainly used in differential positioning for navigation: * ·, * 35 applications, DGPS (Differential Positioning). The implementation is based on the use of two receivers. One of the 13 114273 receivers is a mobile GPS terminal and the other is a fixed receiver such as a base station located in a known location. The corrections relating to the known location, i.e. the base station location, are transmitted, for example, via a radio link to the mobile GPS terminal, which makes the corresponding corrections to its location. In the second method, corrections are made to the pseudoranges between the base station and the satellites detected by the base station. Pseudorange is talked about because the true distance is not precisely known due to the time difference between the clock of the receiver and the transmitter.

However, the differential correction according to the invention differs from the prior art described above in two ways. First, no correction vector is transmitted to the mobile terminal. The other difference is that the distance-weighted effect of multiple gauge receivers is considered.

The flowchart of Fig. 6 illustrates the network status monitoring process.

15 Network status monitoring is performed automatically or manually from the metering receiver control and calculation center. In a first step of the process 600, a measurement receiver is selected to collect the measurement parameters 601. The collected field strength information is compared with the alarm-20 values determined by the measuring receiver control and calculation center and, if necessary, sent to the alarm center 602.

The steps described above are repeated 603 until the measurement parameters of each predetermined measuring receiver have been processed. The process is repeated after a predetermined time 604 or as required.

'25 Status monitoring allows rapid detection of transmitters failures. On the other hand, fault information can also be collected on the transmitter's own. ta condition control unit. Some defects may not appear in the condition control unit. Thus, the condition of the transmitter is not as reliable as: '· what measurement receivers are obtained.

30 An example of such a failure may be the courier. a change in the radiation pattern of the antenna due to environmental conditions, e.g., freezing of the antenna sheath.

In addition, due to the measurement receiver and the field: Y: gain grid used in the calculation, changes in the signal strength of a single radio channel can be detected. An example of such a situation could be as follows. The control and counting unit of the measuring receivers detects a field strength lattice signal of a predetermined lattice signal strength of a base station channel signal of a particular element. However, it is seen from the field gain grid that signal strengths of nearby base station channels are within the allowable limits. The effect of weather or other environmental conditions on the change in signal strength can then be ruled out. It is more likely that the transmitter itself or its component is defective. The information is reported to the system administrator, which can react to the situation.

The flowchart of Figure 7 illustrates the calibration of the design system.

In the first step 700, a prediction lattice element is selected. The field strength of the selected item is calculated with a long-term average of both minimum and maximum values. The calculation utilizes the measurement receiver measurement results stored in the database 111 associated with that item. The obtained minimum and maximum values 15 are stored at 111. When the variation of the field strength values repeats itself frequently enough, the information is sent to the planning system whose propagation model is updated, step 702.

The above steps are repeated 703 until each prediction lattice element used in the calibration is processed. The process is carried out again after a predetermined time 704 or as required.

. As a result of optimization of the design system, the need for field measurements can be reduced. In addition, adding properly dimensioned new base stations, antennas, or other networking devices; the size becomes easier as the field strength values of the design system more closely reflect reality at different times of the year and under different weather conditions.

In one embodiment of the invention, at least a portion of the design system propagation model may be updated in real-time with measurement parameters received from the measurement receivers.

Fig. 8 is a flowchart illustrating the location of a user terminal; determination.

* <· A When the measurement receiver control and calculation center receives a location request 800 from a user terminal, it collects field strength data 801 from the mobile terminal. Alternatively, the information is obtained from the serving base station. Thereafter, the calculating center 106 calculates the mobile terminal position prediction 802 using said field strength information and the above-described interpolated field strength gate. The resulting position prediction is further refined by the correction effect generated in the position correction information process, e.g. depends on the distance of the position prediction to the position prediction of the measuring receiver used. In step 804, the final position prediction is utilized by the location service or the position prediction information is sent directly to the user.

In one embodiment of the invention, the positioning may also be performed so that step 803 of the flowchart is not performed. However, changes in signal strength caused by environmental conditions are taken into account in position determination at step 802.

In one embodiment of the invention, at least some of the measurement receivers are mobile. In this case, the measurement receiver performs measurements at locations 15 whose exact geographical location is known.

Even if the measurement receiver does not transmit measurement parameters per service request but at intervals of up to one hour, the measurement parameters can be considered to be real-time and reliable, especially under stable weather conditions. Whenever necessary, as the weather conditions change, measurement parameters may be requested from the measuring receiver. It is possible to change the measurement interval of the desired measurement receiver and the reporting interval at any time.

Although the invention has been described above with reference to the accompanying examples, it will be apparent to one skilled in the art that the invention may be modified within the scope of the inventive idea set forth above and in the appended claims.

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Claims (15)

A method of correcting an electrical model describing the radio coverage area of a cellular network, characterized in that a measurement parameter is received which at least one measurement receiver (100-102) known from its location has periodically measured from signals which sent by nearby base stations, which measurement parameter describes the radio coverage area at the measurement receiver, the model 10 produced by the planning system (115) describing the radio coverage area using the received measurement parameters is corrected. Method according to Claim 1, characterized in that the method further monitors that the values measured by the measurement receivers are within the limit values specified for them, and is alerted if it is discovered that the parameter value is outside the limit value. Method according to Claim 1, characterized in that the radio coverage area descriptive model is corrected in real time. 20 Method according to claim 1, characterized in that the measurement parameters are collected for a predefined period of time, and the model describing the radio coverage area is corrected at intervals of said time period. Method according to Claim 1, characterized in that the measurement parameter is signal strength, phase or bit / energy of the signal. Method according to claim 1, characterized in that measurement parameters are measured periodically from the signals. Method according to Claim 1, characterized in that the measurement receiver is a fixed installation at a cellular network coverage area. 30 separate row. Method according to claim 1, characterized in that the measurement receiver is implemented in the base station. Method according to claim 1, characterized in that the measurement receiver is mobile. • · 20 114273 Method for determining the location of a mobile terminal in a radio network, in which, by means of the planning system (300), the radio network's coverage area describes descriptive electrical parameters, characterized in that it receives measurement parameters which at least one measurement receiver known from its location location. (302) periodically measured from a signal sent at least by a nearby base station, which measurement parameters describe the radio coverage area, electrical parameters are corrected (303, 304), which describe the coverage area of a radio network in the vicinity of a mobile terminal, with measurement values. received by at least one measurement receiver located near the mobile terminal, it is calculated the location of the mobile terminal using corrected parameters used in the calculation. 15 Method according to claim 10, characterized in that measurement parameters are measured from the signals in response to the mobile terminal's location / location determination request / reservation. 12. A method according to claim 10, characterized in that modified differential correction is used in determining the location, the method further comprising the steps: determined by a location algorithm (305) used in the calculation of a mobile terminal. location location, the location location of at least the nearest measurement receiver (302) of a mobile terminal (309), by inputting in the location algorithm at least one measurement parameter received from said measurement receiver, the operating location returned by the location algorithm, is formed as a result of the comparison at least one correction weight. tor, which corrects the position calculated for the mobile terminal. ··. 30 (311). 13. A system for determining the location of a mobile terminal in one: cellular network, in which, by means of the planning system, electronic parameters have been produced which describe the coverage area of the cellular network, characterized by: that the system hears: at least one measurement receiver (100-102) known from its location, which receives a signal sent from at least one base station sent in its vicinity and measures from this signal at least one measurement parameter, control center (103 ), which receives the measurement parameters fed by the measurement receiver and updates on the basis of them the electrical parameters describing the cellular network coverage area calculation tool (106, 113) for determining the location location of a mobile terminal using electrical parameters. System according to claim 13, characterized in that the update is made periodically. 15. A system according to claim 13, characterized in that the update is made in response to the location reservation of the mobile terminal. * · »· •>> 1 * i» · • · ·