MXPA01011257A - Improvements in radio positioning systems - Google Patents

Abstract

The invention described relates to a radio positioning system primarily for a mobile telephone network, in which a list of offsets in time, phase, frequency, or derivatives thereof, or their equivalents expressed as offsets in distance or derivatives thereof, of a plurality of transmission source signals, received at a given location, relative to a common reference are generated. Data is acquired from one or more receivers, the positions of which may be known or determined. Such data are offsets in time, phase, frequency, or derivatives thereof, respectively of signals received from the transmission sources relative to a reference source in each receiver or to each other. The acquired data is combined for calculating the list of offsets relative to the common reference.

Description

IMPROVEMENTS IN RADIO POSITIONING PROVISIONS The present invention relates, in general, to improvements in radio positioning systems and their methods of operation and, in particular, to methods and apparatus for simplifying the acquisition of data that are required in such provisions EP-A-0 303, 371, the content of which is incorporated in the present application by way of reference, describes a radio navigation and tracking arrangement using independent radio transmitters arranged for other purposes. The signals from each transmitter, taken individually, are received by two receiving stations, one at a fixed and known location, and the other mounted on the mobile object whose position is to be determined. A representation of the signal received at a receiving station is sent by means of a link to a processor at the other receiving station, where the received signals are compared to find their phase differences or time delays. Three such measurements, made in three widely spaced independent transmitters, are sufficient to determine the position of the mobile receiver in two dimensions, ie its position on the ground. The phase or time difference between the master oscillators and the two receivers is also determined.

The "CURSOR" system as described in EP-A-0 303,371 is known, and is a radio positioning arrangement that can use the signals radiated by existing non-synchronized radio transmitters to locate the position of a portable receiver. Unlike some other arrangements that use the temporal coherence properties of purposefully constructed synchronized transmitter networks, the cursor system uses the spatial coherence of the signals transmitted by unique transmitters. In a further development (see EP-A-0 880,712 and WO-A-99/21028), corresponding to the Argentine Patent Application No. P980105626, the technology has been applied to find the position of a mobile telephone in a GSM system or another digital telephone system, and these are examples of an "Enhanced Observed Time Difference" (E-OTD) method using the downlink signals radiated by the Base Transceiver Stations network (BTS station) of the telephone set-up. In the digital mobile phone application described in EP-A-0 880,712, the content of which is incorporated herein by reference, the signals coming from each BTS station within the reach of the telephone are received both by the telephone itself as by a fixed near receiver, the Location Measurement Unit (LMU unit) whose position is precisely known.

Representations of the received signals are passed to a Mobile Location Center (MLC) where they are compared in order to find the time difference between them. Figure 1 shows the geometry of a standard two-dimensional arrangement. The origin of the Cartesian coordinates x and y is centered in the LMU unit positioned at 0. The orientation of the axes is not important, but conveniently it can be arranged so that the y axis is along the local north-south map grid . The telephone, R, is in a position vector r with respect to the 0 position of the LMU unit. A BTS station, A, is shown in the position vector a. Consider first the signals coming from the BTS station A. The difference in time,? A has, measured between the signals received in R and in 0 is given by ?? a = (| r - al - lal) /? + e, where ? is the velocity of the radio waves, e is the deviation of clock time between the clocks in the receivers in R and in O, and the vertical bars on each side of a quantity of vector indicate that it is the magnitude of the vector that is used for the formula. The value of e represents the synchronization error between the measurements made by the two receivers. Similarly, they can be written for two other BTS stations (B and C) in position vectors b and c (not shown): ?? b = (| r - b | - | b |) /? + e, ? tc = (| r - c \ - | c |) /? + e (1) The values of ?? a, ?? b, ?? c, are measured by the methods disclosed in EP-A-0 880,712 and the values of a, b, c, and? are known, therefore formulas 1 can be solved to find the position of the telephone, r together with the value of e. In WO-A-99/21028 whose "content is incorporated in the application by way of reference, it is described how these same time deviations can be measured using templates created locally in a GSM telephone system as follows: Assume that the telephone has registered a short sequence of the GSM signals coming from the BTS A station. Contained within that register is the structure of 'frame, synchronization runs and other data' given '(or predetermined values) that are a constant characteristic of those Transmissions The processor inside the telephone can create a correspondence template, based on the known structure of the network signals, then the received signals can be matched with the locally generated template. correlation at the position of best correspondence corresponds to the time deviation between the signals received days and the local clock inside the phone. For the signals radiated by the BTS station A this deviation of measured time, ?? a, is given by ??to? = (| r - a |) /? + aa + e ?, where aa is the time deviation of the transmission of the BTS station and e ± is the time deviation of the internal clock of the telephone, both relative to a universal and imaginary "absolute" clock. The signals coming from BTS stations B and C can also be measured in the same way, giving ? i i = (| r - b |) /? + ab + e ?, ?? c? = (| r - c |) /? + ac + e ?, (2) The same measures can be carried out by the LMU unit, giving ?? a2 = (| a |) /? + aa + e2, ?? b2 = (| b |) /? + ab + e2, ? C2 = (| c |) /? + ac + e2, (3) where e2 is the time deviation of the internal clock of the LMU units in relation to the same imaginary universal absolute clock. Subtracting formulas 3 from formulas 2 yields ??,? m - ??, a2 | r - al - lal) /? + a + e, ? xb = ?? b? - ?? b2 = (| r - b | - | b |) /? + a + e, Y ?? c ?? c? -? i, c2 | r - c | - | c |) /? + a + e, (4) where e = ei - e2. It will be appreciated that the formulas 4 are the same as the formulas 1, and can be solved in the same way to find the position of the telephone r and the value of e. It will be evident that the CURSOR method, in common with all other methods that use the signals from non-synchronized transmitters, requires that a network of LMU units be arranged within the coverage area of the telephone provision. These units act as reference points in which the non-synchronized signals radiated by the BTS stations are measured for comparison with the same signals received by a telephone. Each position measurement requires a correspondence between the signals received by the telephone from a number of nearby BTS stations, and signals received by an LMU unit from the same BTS station set. In practice, it is often difficult to find a match using only one LMU unit, especially if the LMU unit network is scarce, since the telephone can receive signals from the BTS station not received by the LMU unit and vice versa. Therefore, it is necessary to combine measurements from two or more LMU units. However, each new MU unit put into the calculation adds an additional unknown clock time offset (e2, e3 etc.), each of which therefore requires an additional BTS station measurement to provide the additional equation that is You need to solve all of the unknown quantities. A solution to this problem is presented in WO-A99 / 21028 where it is shown how the LMU unit network can be synchronized. With reference to figure 2Suppose that an adjacent pair of LMU, Ui and U2 units can see a common BTS station. The positions of the LMU units and the BTS station are all known, so that a single measurement of the BTS station signals for each LMU unit is sufficient to determine the deviation of clock time between the LMU units. For example, suppose that the distance from Ui to station BTS is yes, and the distance from U2 to station BTS is s2. Ui measures the time deviation? Ii and U2 measures the deviation of time ?? 2, given by ?? 2 = sx /? + a + e22 (5) where a is the time offset of the BTS stations, and e2? and e22 are the time deviations of the internal clocks of the LMU units in Ui and U2 respectively. Subtracting the second equation from the first equation gives e2? e22? ti - ?? 2 + s? /? -s2 /? (6) which is the relative time deviation of the clock in Ui from the clock in U2. This procedure can be repeated for a second pair of LMU units, for example U2 and U3, and another BTS station whose signals can be received by both members of this second pair of LMU units. In this way, a synchronization map can be calculated, which provides the clock deviations of all the internal clocks of the LMU units relative to one of them adopted as a "LMU unit network clock time". Having thus established the synchronization map of the LMU units, a position measurement of CURSOR can then include any number of LMU units without the disadvantage of adding an additional unknown time offset for each LMU unit, since deviations are known. of relative times of the LMU units. The receivers described in the preceding paragraphs make measurements of time deviations. More generally, receivers can measure time deviations, phase deviations (which can be converted to time deviations with a 360 ° ambiguity module), frequency deviations or frequency deviation change regimes. Although these measurements are of different amounts, the present invention is usefully applied to each of them, since, when combined with similar measurements made by a second receiver, they can independently provide positional information. The positioning arrangements using these measurements are described in a related patent application filed simultaneously with the present. The present invention discloses how the same advantages of a synchronized LMU network (efficiently) can be obtained by arranging one or more "virtual" LMU units in the network that act as interface nodes for the real LMU units. According to a first aspect of the invention, there is provided a method of generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as distance deviations or derivatives thereof, of a plurality of transmission source signals, received at a given location, relative to a common reference, the method comprising: (a) acquiring data from one or more receivers, the positions of which may be known or determined, the data from a receiver comprising deviations in time, phase, frequency or derivatives thereof respectively from signals received from the transmission sources relative to a reference source in each receiver or from each other, and (b) combining the acquired data and calculating the list of deviations relative to the common reference. In practice, deviations from the list can be used instead of deviations obtained directly from the receiver or receivers. The relative deviations in time, phase, frequency, or derivatives thereof, among themselves or with respect to reference sources, of the signals received by a first receiver coming from a plurality of transmission sources can be represented by corresponding deviations or differences in the distances between the sources of transmission and the first receivers or second receivers.

The invention also includes apparatuses that use the method described above, the apparatus comprising: (a) elements for acquiring data from one or more receivers, the positions of which may be known or determined, the data from a receiver comprising deviations in the time, phase, frequency or derivatives thereof respectively of signals received from the transmission sources relative to a reference source in each receiver or to each other, and (b) elements to combine the acquired data and calculate the list of deviations relative to the common reference. In a method using techniques similar to or as described in EP-A-0 880 712, instead of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as deviations in distance or deviations from the Data representative of the signals can be used, from which the deviations of signals received from the transmission sources relative to the reference source can be determined. Therefore, the invention also includes a method for generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as distance deviations or derivatives thereof, of a plurality of source signals of transmission, received at a given location, relative to a common reference, the method comprising: (a) acquiring data from one or more receivers, the positions of which may be known or determined, the data of a receiver being representative of the signals received; (b) determining from the acquired data the deviations in time, phase, frequency, or derivatives thereof respectively of signals received from the transmission sources relative to a reference source or to each other; and (c) combine the deviations determined in this way and calculate the list of deviations relative to the common reference. The invention also includes apparatuses for carrying out the method described immediately above, the apparatus comprising: (a) elements for acquiring data from one or more receivers, the positions of which may be known or determined, being the data of a receiver representative of the signals received; (b) elements for determining from the acquired data the deviations in time, phase, frequency, or derivatives thereof respectively of signals received from the transmission sources relative to a reference source or to each other; and (c) elements to combine the deviations determined in this way and calculate the list of deviations relative to the common reference. A radio positioning method and arrangement that includes the methods and apparatus defined above is also part of the present invention. The invention also includes apparatuses (a virtual LMU unit) for carrying out either or both of these methods. The apparatus may include a computer (located at any convenient location) and programmed to carry out the required procedure. Although the following description of a particular application of the invention refers to signals in a digital telephone network, it will be evident that the invention is not in any way restricted to this application, but can be applied to any network of one or more transmitters, synchronized or not synchronized, ready for any purpose. A virtual LMU unit includes a computing process that can be executed on any computing platform that can obtain data from real LMU units. Accordingly, a further aspect of the invention includes a method of calculating and maintaining a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as distance deviations or derivatives thereof, of a plurality. of signals from transmission sources, received at a given location, relative to a common reference. It is assumed that the BTS station network is non-synchronized in that the transmission time deviations of the BTS station signals have no constant or known relationship with each other, but that in any case the BTS station oscillators are quite stable, so that their instantaneous frequencies change only slowly over time. In these circumstances, it is possible to predict the deviation commonly received in time, phase, frequency or derivatives thereof from the signals coming from a BTS station given by a real LMU unit given from sufficiently recent historical data. The real LMU units in the network make measurements of all the BTS stations that they can detect in a cyclic way, repeating the cycle every few seconds. They keep these measurements in a stack, replacing the oldest measurements with the most recent ones. Therefore, a linear or polynomial low-order fit in the measurements provides a predictor for extrapolation in the near future, or for interpellation in the recent past. Assume that the BTS station oscillators are sufficiently stable that reliable predictions can be made for a period of, for example, 10 minutes. Then, every few minutes, the virtual LMU unit (V LMU) contacts each real LMU unit and receives its predictors for the deviations received from the signals coming from all the BTS stations in its measurement set. It is likely that many of the BTS stations have been measured by more than one LMU unit, so the V LMU unit analyzes the complete data set from all the real LMU units using well known methods to determine (a) the best values of real internal LMU unit clock deviations in time, phase, frequency, or derivatives thereof, and therefore (b) the deviations received in time, phase, frequency, or derivatives thereof from the signals from all BTS stations that would have been measured by an LMU unit. real located in the assumed position of the V LMU and capable of receiving signals from all BTS stations. In the above description of the function of the V LMU, it should be understood that any or all of the LMU units could have been replaced by other receivers, not necessarily fixed or in known positions, that have not been specifically arranged as LMU units. For example, data from a number of phones could be used to determine frequency deviations if the telephones were stationary. Also, it is demonstrated in a related patent application filed simultaneously with the present, as the telephone positions and speeds can be determined without the need of any LMU unit in any way. The particular advantages of using a V LMU unit in a network include the following: (a) a full correspondence between phone measurements and a single LMU (virtual) unit can be guaranteed; (b) the procedure of the unit V LMU minimizes the timing errors in measurements of individual LMU units; (c) the list of units V LMU is immediately available for the procedure of calculation of positions, increasing the speed of computation; (d) when combined with the ideas described in a related patent application that is presented simultaneously with the present, a list of reception time deviations can be created in a BTS station network where there are few LMU units, if any; (e) the V LMU unit provides, in effect, a synchronization map of the real LMU unit network, whose network can then be used to monitor the BTS station network and, in particular, to determine newly installed BTS station locations. . An example and a method and apparatus acing to the present invention will be described below with reference to the accompanying drawings, in which: Figure 1 shows the geometry of a CURSOR system as described in EP-A-0 880 712. Figure 2 shows adjacent LMU units making measurements of a common BTS station. Figure 3 shows a network of real and virtual LMU units in an arrangement of the invention. Figure 4 illustrates a similar, simplified network. Figure 5 shows the positions of sites of LMU units and sites of BTS stations in a real network. Figure 6 shows the same network with the addition of a virtual LMU unit. Figure 7 shows the same network with the real LMU units replaced by the virtual LMU unit. Figure 8 illustrates, as a flow chart, the processing that takes place within an LMU unit. Figure 9 illustrates, as a flowchart, the processing that takes place within a V LMU unit. Figure 10 shows a list of chronization deviations generated in a real arrangement such as that shown in the examples of figures 5 to 9; and Figure 11 shows a table of cronization errors associated with LMU units and a virtual LMU unit in this example. By way of example, and with reference to Figure 3, the function of a virtual LMU unit that determines chronization deviations is described below. Consider a network of N real LMU units and M BTS stations that includes a virtual LMU unit ((V LMU) The position of the LMU unit of order n, Un, is represented by the vector a and the position of the BTS station of order m, Bm, is represented by the vector bm, both vectors being in relation to the same origin The signals radiated by the BTS m station will be received by the unit LMU n after a delay of time, and the measurements of this time delay ,? inm is given by ?? p | n-b /? + en + am sp (7) where in is the deviation of clock time of the unit LMUn, p is the deviation of transmission time of the BTS station m, both with respect to an imaginary universal "absolute" clock, and snm is an estimate of the error in the measurement of ? tnm. The assumed position of the virtual LMU unit is represented by the vector v. If the LMU unit could receive the signals directly from the BTS station m without error, then it would measure a reception time offset, ßm, relative to the imaginary universal absolute clock, given by Substituting for am in equation (7) using the value deduced from equation (8) is provided ?? = U | /? + en + ßm- | v-bra | /? + sp (9) Throughout the network of N LMU units, all of the M BTS stations are visible. However, each individual LMU unit will only see a few of them, but whenever there is a significant visibility overlay, it is possible to take the set of all the values? I and solve to obtain the values of in and ßn- Therefore the V LMU unit can calculate errors for any BTS station as if the network of LMU units is synchronized, or as if only one LMU unit (the LMU V unit) is all that is needed to cover the entire network of BTS stations. To illustrate this additionally, a simplified problem using N = 2 and M = 4 is shown below and is solved., ie a network consisting of only two LMU units that monitor 4 BTS stations (see Figure 4). For reasons of simplicity it is chosen that ei = 0. This is allowed since the "absolute" clock time is completely arbitrary, and can, for example, be measured by the internal clock of the LMU unit number one. (It should be noted, however, that this choice introduces an asymmetry in the solution and that the error associated with BTS stations three and four are not the same). The first LMU unit (Ui) can receive signals from the numbers of BTS stations one, two and three, but can not receive signals from the BTS station number four. The second LMU unit (U2) can receive the signals from the BTS stations one, two and four, but can not see the BTS station number three. The equations can be written in matrix form as or equivalently as A.x = b + Z where Z is an unknown vector of the real errors in each measurement. The standard technique known as "minimum squares" postulates that the estimate for x that minimizes Z is given by X = (ATWA) _1 AtWb, (11) where the symbol At indicates that the transposition of the matrix A, and the matrix W is defined by This particular example can be solved explicitly. For reasons of simplicity, it is assumed that all the values of o ^ are the same, and equal to s. This gives the result - (3Dn + D12 + D21 - D22) / 4 ± 0.87s, ßi = (3D12 + Dn + D22 - D21) / 4 ± 0.87s, /% = D13 ± l .OOs, (13) ß = (2D24 + D + - O21 - O22) / 2 ± 1.41 s, e2 = (D21 + D22 - D ^ - D12) / 2 ± 1.00s, where u -b "- v-b. D nm = At nm (14)? It should be noted that even in this simple case, when a BTS station is viewed by both LMU units, the errors in the capped deviations are less than the errors in each of the measurements themselves. This is an important advantage of the virtual LMU unit method. The LMU units may also contain other synchronization elements. For example, each real LMU unit could be connected to a GPS or other G cronization reference receiver, which serves to provide the common timing reference. In this case, the network of LMU units can be considered as already synchronized to this common chronization reference (ie the standard GPS time), and then it is not necessary for the V LMU unit to be resolved to obtain the individual values of e, since these are already known. An advantage of using other synchronization elements is that there is no longer a requirement for visibility overlay of BTS stations between adjacent LMU units. If each BTS station site also carried an LMU unit, then that LMU unit should only be able to receive signals (very intense) from its transmitter or transmitters of BTS stations in the same site, thus simplifying the installation of the antenna of the LMU unit. The operation LMU unit mode described above may be referred to as the "firing mode", since it requires the LMU unit to instigate data transfer for it from each real LMU unit. It is also possible to make each real LMU unit continually check the difference between its own prediction of the reception time offset of each BTS station using calculated values from the set of predictors ultimately sent to the unit V LMU and the actual measured values. When any of these differences exceeds a given value, the LMU unit can send its new predictor set to unit V LMU. This mode of operation can be called "push mode". The particular mode appropriate for a real arrangement depends, among other things, on the stability of the network of BTS stations. Next, an example of a prototype arrangement constructed in accordance with the invention will be described, in which the chronization measurements made by a number of LMU units are combined to create a list of reception time deviations for all GSM BTS stations. in and around Cambridge, United Kingdom, as if they were observed by a single "Virtual" LMU unit. The positions of nine LMU units, Ui-U9 (shown as filled circles) and twenty-three BTS stations in the Cambridge area, Bi-B23 (shown as unfilled squares) are plotted in Figure 5 of the grid. ordinance protection (OS). Each LMU unit comprises (a) hardware that includes an internal clock, a GSM radio, a computer, and a telephone connection, and (b) software that includes a program to compile a list of reception time deviations. Figure 8 illustrates, by means of a flow diagram, the main software elements of the LMU unit residing in each LMU unit, Ui-Ug. Every few seconds, the "scan cycle" program is entered in stage Al.

The program continues, in stages A2, A3, A6 and A7, to tune the GSM radio to each GSM transmission channel at a time, and to scan for BCCH signaling. In the event that a BCCH signal is detected in step A3, the program calculates the time deviation of reception of the signal relative to its internal clock (in step A) and updates its list of time deviations accordingly in step A5 . The BCCH is also decoded to produce the identification of the BTS station Bn from which the signal is received. Figure 5 also shows lines between the LMU units and the BTS stations detected by them as a result of the scan cycle routine. Figure 6 shows the positions of the nine LMU units, the twenty three BTS stations monitored by those LMU units and one virtual LMU unit V (indicated as an unfilled circle). The virtual LMU unit V comprises (a) hardware that includes a telephone connection to each real LMU unit and a computer, and (b) software that includes a program for compiling a list of "virtual" reception time deviations. Figure 9 illustrates, by means of a flowchart, the main elements of the V LMU software. Every 4 minutes, the "V LMU unit update" program is entered in stage VI. The program passes, in stages V2, V3, V5 and V6, to connect each of the real units by means of telephone connections. If the connection to a given LMU unit U-Ug is successful, the program, in step V4, extracts that list of LMU units from reception time deviations. When the connection cycle is completed, the program (in step V7) combines the data to produce a list of reception time deviations for all of the BTS stations monitored by the network of LMU units. An example of this list is shown in Figure 10, where a part of a table of reception time deviations generated by the V LMU is reproduced. The first column shows the BTS station identifier and the figures in the table are in units of 1.85 microseconds. Figure 6 also shows lines between the V LMU V unit and each real LMU unit, Ux-U9 of which the V LMU software can extract a list of time deviations. Once the "V LMU update" has been completed, the combined list of generated cronizations is equivalent to what would have been observed if there had been a single LMU unit (real) at the location of the V LMU units making measurements of chronization of each BTS station in the network. Figure 7 illustrates this equivalence showing the virtual monitoring of the timing measurements of each BTS station by the virtual LMU unit (shown as lines between the V LMU V unit and the BTS B-B23 stations).

Each chronization measurement has an associated error that, in most cases, is smaller than the errors in the chronization measurements made by the individual real LMU units. This is illustrated in the table of Figure 11, which shows part of the list produced by the V LMU unit during operation. The first column shows the identifier of each BTS station. Columns 1 to 9 refer, each to a particular of the 9 real LMU units. The figures in the table are errors in the chronization measurements made by the real LMU units of the signals coming from the corresponding BTS stations. An empty cell indicates that the LMU unit is unable to receive a signal from BTS stations. The column headed by V LMU shows the result of the combination of the measurements using the method described above. The timings in the table of Figure 11 are in units of 1.85 microseconds. It should be noted that the timing errors of V LMU units are generally smaller than those estimated for real LMU unit cronisations, confirming an advantage of the V LMU method to reduce errors.

Claims (15)

1. CLAIMS 1. A method of generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as distance deviations or derivatives thereof, of a plurality of transmission source signals, received at a given location, relative to a common reference, the method comprising: (a) acquiring data from one or more receivers, the positions of which may be known or determined, the data from a receiver comprising deviations in time, phase, frequency or derivatives thereof respectively of signals received from the transmission sources relative to a reference source in each receiver or to each other; and (b) combining the acquired data and calculating the list of deviations relative to the common reference.
2. 2. A method for generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as deviations in distance or derived therefrom, from a plurality of transmission source signals, received in a given location, relative to a common reference, the method comprising: (a) acquiring data from one or more receivers, the positions of which may be known or determined, the data of a receiver being representative of the received signals; (b) determining from the acquired data the deviations in time, phase, frequency, or derivatives thereof respectively of signals received from the transmission sources relative to a reference source or to each other; and (c) combine the deviations determined in this way and calculate the list of deviations relative to the common reference.
3. 3. A radio positioning method for determining the position of one or more receivers, the positions of which are unknown, which method includes the method according to claim or claim 2.
4. A radio positioning method according to claim 3, wherein the common reference comprises an external reference.
5. 5. A radio positioning method according to claim 4, wherein the common reference comprises a GPS signal.
6. 6. A radio positioning method according to any of claims 3 to 5, wherein the step of acquiring data from said one or more receivers includes instigating the acquisition of said data from a common location.
7. A method of radio positioning according to any of claims 3 to 5, wherein the step of acquiring data from said one or more receivers includes instigating the acquisition of said data from each of said receivers at times determined by each of said receivers.
8. 8. Apparatus for generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as deviations in distance or derived therefrom, from a plurality of signals from transmission sources, received in given locations , relating to a common reference, the apparatus comprising (a) elements for acquiring data from one or more receivers, the positions of which may be known or determined, the data coming from a receiver comprising deviations in time, phase, frequency or derived therefrom respectively from signals received from the transmission sources relative to a reference source in each receiver or from each other, and (b) elements to combine the acquired data and calculate the list of deviations relative to the common reference.
9. 9. Apparatus for generating a list of deviations in time, phase, frequency, or derivatives thereof, or their equivalents expressed as deviations in distance or derived therefrom, from a plurality of signals from transmission sources, received in given locations , relating to a common reference, the apparatus comprising (a) elements for acquiring data from one or more receivers, the positions of which may be known or determined, the data of a receiver being representative of the signals received; (b) elements for determining from the acquired data the deviations in time, phase, frequency, or derivatives thereof respectively of signals received from the transmission sources relative to a reference source or to each other; and (c) elements to combine the deviations determined in this way and calculate the list of deviations relative to the common reference.
10. A radio positioning arrangement that includes an apparatus according to claim 8 or claim 9.
11. A radio positioning arrangement according to claim 10, wherein the common reference comprises an external reference to said receivers.
12. 12. A radio positioning arrangement according to claim 11, wherein the common reference comprises a GPS signal: 13.
13. A radio positioning arrangement according to any of claims 10 to 12, wherein the elements for acquiring data from said one or more receivers includes a computing arrangement arranged to instigate the transfer of said data from said one or more receivers to said computing arrangement at times determined by said computing disposition.
14. A radio positioning arrangement according to any of claims 10 to 13, wherein the elements for acquiring data from said one or more receivers includes a computing arrangement and includes elements to instigate said acquisition of data from each one of said receivers at times determined by each of said receivers.
15. 15. A digital telephone network, including a radio positioning arrangement according to any of claims 10 to 14.