A method for locating mobile units, wherein for each of the mobile units, wireless signal measurements are obtained from transmissions between the mobile unit and a plurality of terrestrial communication stations, and wherein the mobile unit is independently moveable from each of the communication stations, and each of said communications stations includes one or more of:
- a transmitter for transmitting wireless signals to the mobile units, and a receiver for receiving wireless signals from the mobile units, comprising:
- first requesting a location of a first of the mobile units;
- second requesting a location of a second of the mobile units;
- wherein for at least the first mobile unit, one of the following location techniques (A-1) through (A-5) is used for locating the first mobile unit, and for at least the second mobile unit, a different one of the following location techniques (A-1) through (A-5) is used for locating the second mobile unit;
- (A-1) a first technique for recognizing a pattern of wireless signal transmission characteristics, wherein said pattern of characteristics is indicative of a plurality of wireless signal transmission paths between the mobile unit and each of one or more of the communication stations;
- (A-2) a second technique for estimating a location of said mobile unit, wherein the following steps (A-2-1) through (A-2-3) are performed:
- (A-2-1) determining a time difference of arrival (TDOA) location estimate of said mobile unit based upon timing information of signals transmitted between the mobile unit and the communication stations;
- (A-2-2) determining a timing advance (TA) location estimate for the mobile unit and at least one of the communication stations;
- and
- (A-2-3) determining a location of the mobile unit using the TDOA location estimate, and the TA location estimate;
- (A-3) a third technique for estimating a location of said mobile unit, wherein the following steps (A-3-1) through (A-3-3) are performed:
- (A-3-1) obtaining a first measurement for a time of travel of a transmission transmitted by a wireless transmitter not supported on the earth's surface, wherein the transmission is received at the mobile unit;
- (A-3-2) obtaining a second measurement for a time of travel of a transmission communicated between the mobile unit, and one of the communication stations (CS) of a cell based communications system providing wireless two-way communication with a plurality of additional mobile units;
- and
- (A-3-3) determining a position of said mobile unit using at least the first measurement to determine a geographical extent from the transmitter, and the second measurement to determine a geographical extent from the communication station CS;
- (A-4) a fourth technique for estimating a location of said mobile unit using values of at least one location related characteristic of signals communicated between the mobile unit and the communication stations, wherein the following steps (A-4-1) through (A-4-10) are performed:
- (A-4-1) estimating a channel power profile for each of M samples received at one of the communication stations;
- (A-4-2) selecting a first set of N samples from the M samples;
- (A-4-3) performing incoherent integration for said estimated channel power profiles for said first set of N samples to form a first integrated signal;
- (A-4-4) if a quality level of the first integrated signal with respect to signal to noise is less than a predetermined threshold, selecting another sample from the M samples;
- (A-4-5) performing incoherent integration for the estimated channel power profiles for said first set of N samples and said another sample to form a second integrated signal;
- (A-4-6) if a quality level of said second integrated signal with respect to signal to noise is greater than or equal to said predetermined threshold, determining a location related signal characteristic value for a maximum level of the second integrated signal;
- (A-4-7) using the signal characteristic value to provide a corresponding entry in a frequency of occurrence data structure;
- (A-4-8) selecting a second set of N samples from the M samples;
- (A-4-9) repeating all of the steps (A-4-3) through (A-4-7) for the second set of N samples;
- and
- (A-4-10) determining a preferred value for the signal characteristic from the frequency of occurrence data structure;
- and
- (A-5) a fifth technique for estimating a location of said mobile unit, wherein the following steps (A-5-1) and (A-5-2) are performed:
- (A-5-1) determining a joint probability from location related information obtained from each of two different location providing information sources;
- and
- (A-5-2) using the joint probability to determine a location estimate of the mobile unit;
- combining the values indicative of amplitude and phase for two tone components of signals received at the communication stations to determine the position of the mobile unit;
- first obtaining a first information of a location of the first mobile unit;
- second obtaining second information of a location of the second mobile unit;
- first obtaining first additional information using:
- (a) the first information, and (b) information for a first destination determined using an input for identifying a first one or more geographic locations of interest, wherein when at least a first geographical condition related to both the location of the first mobile unit and the information for the first destination is satisfied, the first additional information includes information for a user of the first mobile unit to access the first destination;
- second obtaining second additional information using:
- (a) the second information, and (b) information for a second destination determined using an input for identifying a second one or more geographic locations of interest, wherein when at least a second geographical condition related to both the location of the second mobile unit and the information for the second destination is satisfied, the second additional information includes information for a user of the second mobile unit to access the second destination;
- first transmitting the first additional information to the first mobile unit;
- and
- second transmitting the second additional information to the second mobile unit.