Abstract: The invention relates to a method for determining the phase of information modulated in a code-modulated signal transmitted by a satellite in a receiver (MS). In the method, at least partly the same information is transmitted from at least a first and a second satellite (SV1-SV4) substantially simultaneously, the code-modulated signal transmitted from at least the first and the second satellite (SV1-SV4) is received, and at least the received signal of the first satellite is demodulated to determine the transmitted information.

Abstract: A positioning system based on an extended Kalman filter (EKF), or other filter, responsive to measurements provided on the basis of information received from, in some applications, cellular base stations, as well as, optionally, satellites, where, in the case of measurements by satellites, and also in other aspects of the invention as used with cellular positioning data, the EKF is modified for greater responsiveness based on use of calculated association probabilities for each measurement in a set of measurements of position at a particular instant of time, the association probabilities used in the calculation of a combined measurement innovation (residual) used in calculating the next estimate of position (and other state information, including velocity). By using a combined measurement innovation, the positioning system is able to accept simultaneous measurements based on information received from different sources of information, including both satellites and cellular base stations.

Abstract: A code modulated signal transmitted by satellites (SV1-SV4) and formed by an individual code for each satellite (SV1-SV4) is received. At least one reference point (B) is selected, whose position is substantially known. Information is transmitted to the positioning means (S, MS) about the position of the at least one reference point, and about Ephemeris data on the satellites (SV1-SV4). Thus, at least the Ephemeris data on each of the satellites (SV1-SV4) to be used in the positioning and the location of the at least one reference point are used in the positioning of the receiver.

Abstract: A system, apparatus, and corresponding method for measuring a pseudorange from a ranging receiver to a beacon (such as a GPS satellite). It determines the time of transmission of a target ranging signal fragment (for which the difference in time between transmission and reception is essentially the pseudorange) even in poor signal conditions when the navigation data of the ranging signal cannot be accurately decoded by the ranging receiver. It is based on making either an estimate of the start time for the particular information element of the ranging signal (usually a navigation data bit) beginning just before the target ranging signal fragment (if the quality of the ranging signal allows such an estimate to be made), or (in any case) based on making an estimate of the time corresponding to the start of the code epoch of the ranging signal that just precedes the target ranging signal fragment.

Abstract: A method and apparatus for measuring time related to satellite navigation data messages used with a satellite-based global positioning systems (GPS). A first record of at least a portion of a satellite data message is received at an entity, which is typically a base station of a wireless communication system. The first record is compared with a second record of the same satellite data message (navigation message) received by a GPS receiver. From the comparison, a time is determined indicating when the satellite date message was transmitted (broadcast). The comparison is made in a way that accounts for the only approximate removal of all modulation of the satellite data message by the acquisition and tracking stages of the GPS receiver.

Abstract: The invention relates to a method for determining an error in the reference time (15) of a receiver (MS) in positioning means (S,MS). In the method, a code modulated signal transmitted by satellites (SV1-SV4) is received the signal being formed with an individual code for each satellite (SV1-SV4). In the method, the time ({circumflex over (T)}ToTk) of transmission of the signal received from every satellite used in the positioning is determined to be used in determining the position of the satellite. To determine a difference between the time ({circumflex over (T)}ToTk) of transmission of the signal and the reference time, positioning is performed, and on the basis of the determined position, an error value (ERR) is calculated.