Method and system for localizing mobile communication terminals

A system for determining a geographic position of a mobile communications terminal operable in a wireless communications network and comprising a receiver of signals of a global navigation satellite system comprising:

• first calculation modules operable to calculate a first estimated position of the mobile communications terminal based on pseudo-range measurements related to a plurality of signals received from transmitters of the global navigation satellite system;
• second calculation modules operable to calculate a second estimated position of the mobile communications terminal based on information provided by the wireless communications network;
• estimated position analysis modules operable to derive an indication of whether at least one of the pseudo-range measurements is affected by errors by comparing the first estimated position to the second estimated position to determine whether an estimated accuracy of the first estimated position is higher than an estimated accuracy of the second estimated position and, in case an indication is derived that at least one of the pseudo-range measurements is affected by errors as a result of said determining, further operable to:
• cause the first calculation modules to recursively calculate at least one third estimated positions based on pseudo-range measurements related to a respective sub-set of said plurality of signals received from transmitters of the global navigation satellite system, wherein each recursive calculation excludes a different pseudo-range measurement, and calculate at least two third estimated positions, each third estimated position corresponding to a different sub-set of said plurality of signals received from transmitters of the global navigation satellite system;
• evaluate whether each of the at least two third estimated positions is more accurate than the first estimated position;
• and
• in the affirmative case, take as estimated position of the mobile communications terminal the third estimated position that is closer to the second estimated position.

A mobile communications terminal operable in a wireless communications network and comprising a receiver of signals of a global navigation satellite system, comprising:

• a calculation module operable to calculate a first estimated position of the mobile communications terminal based on pseudo-range measurements related to a plurality of signals received from transmitters of the global navigation satellite system;
• an estimated position analysis module operable to receive a second estimated position from the wireless communication network and to derive an indication of whether at least one of the pseudo-range measurements is affected by errors by comparing the first estimated position to the second estimated position to determine whether an estimated accuracy of the first estimated position is higher than an estimated accuracy of the second estimated position and, in case an indication is derived that at least one of the pseudo-range measurements is affected by errors as a result of said analyzing, further operable to:
• cause the calculation module to recursively calculate at least one third estimated position based on pseudo-range measurements related to a respective sub-set of said plurality of signals received from transmitters of the global navigation satellite system, wherein each recursive calculation excludes a different pseudo-range measurement, and calculate at least two third estimated positions, each third estimated position corresponding to a different sub-set of said plurality of signals received from transmitters of the global navigation satellite system;
• evaluate whether each of the at least two third estimated positions is more accurate than the first estimated position;
• and
• in the affirmative case, take as estimated position of the mobile communications terminal the third estimated position that is closer to the second estimated position.