Tracking radio signal sources
A method and system of determining the position of a radio signal transmitter are described. The method includes determining the type of radio signal being transmitted from the radio signal transmitter by analysing radio signal characteristics and correlating different sets of information to determine the position of the radio signal transmitter. Each set of information corresponds to a different relative position of at least one receiver to the transmitter and includes radio signal data derived from radio signals received by the at least one receiver from the transmitter at each respective relative position and positioning data containing information about the position of the at least one receiver at each respective relative position.
1. A method of determining a position of a radio signal transmitter comprising;
determining a type of radio signal being transmitted from the radio signal transmitter by analyzing the radio signal for radio signal characteristics; and
correlating different sets of information in a way dependent on the determined radio signal type in order to determine the position of the radio signal transmitter;
wherein each set of information corresponds to a different relative position of at least one receiver to the transmitter, each set of information comprising:
radio signal data derived from radio signals received by the at least one receiver from the transmitter at each respective relative position; and
positioning data containing information about a position of the at least one receiver at each respective relative position,
wherein the method further comprises:
assessing dynamics of a platform on which the radio signal transmitter is supported, and correlating the different sets of information in a way dependent on the determined dynamics of the platform, and
wherein determining the type of radio signal being transmitted from the radio signal transmitter comprises determining whether the type of radio signal originates from a movable radio signal source or a stationary, immovable radio signal source, and when the type of radio signal originates from a movable radio signal source, repeating the correlating of different sets of information to track the mobile radio signal source.
2. A method according to claim 1 wherein determining whether the type of radio signal originates from a mobile radio signal source or a stationary radio signal source includes:
analyzing the radio signal characteristics of the radio signal,
consulting a database, and
inferring the type of radio signal source.
3. A method according to claim 1 , wherein a plurality of receivers are arranged to be in communication with one another so that they can share the different sets of information.
4. A method according to claim 1 , wherein at least one of the sets of information comprises:
radio signal time of flight values/ranges.
5. A method according to claim 1 , wherein at least one of the sets of information comprises:
radio signal strength values/ranges.
6. A method according to claim 1 , wherein at least one of the sets of information comprises:
radio signal arrival angle values/ranges.
7. A method according to claim 1 , comprising:
querying a database to determine how to correlate the different sets of information, the database having a set of rules mapping different sets of radio signal characteristics to different ways of correlating the sets of information.
8. A method according to claim 7 , comprising:
updating the database by at least one of downloading additional rules and receiving user input.
9. A method according to claim 1 , further comprising:
presenting a user interface to receive information about at least one of mobility of the radio signal transmitter, a bearing value/range of the radio signal transmitter relative to a given receiver, an estimated position value/range of the radio signal transmitter, and an estimated type of the radio signal transmitter.
10. A method according to claim 1 , comprising:
presenting a user interface to display information about the radio signal transmitter, the displayed information including a map on which a representation of the radio signal transmitter is imposed, the representation including an error ellipse, a size and shape of which are representative of an error associated with estimated position of the radio transmitter.
11. A method according to claim 1 , wherein the correlating of data comprises:
applying a Bayesian estimation filter.
12. A method according to claim 11 , wherein application of the Bayesian estimation filter comprises:
loading the filter with a model associated with the determined type of radio signal transmitter.
13. A method according to claim 1 , comprising:
estimating the position of a radio signal receiver by:
estimating a position of a first stationary radio signal transmitter using a primary set of positioning resources available to the receiver;
adding the position of the first transmitter to a secondary set of positioning resources available to the receiver; and
using the secondary set of positioning resources to estimate the position of the receiver.
14. An apparatus for determining a position of a radio signal transmitter, comprising:
means for determining a type of radio signal being transmitted from the radio signal transmitter by analyzing the radio signal for radio signal characteristics, and for correlating different sets of information in a way dependent on the determined radio signal type in order to determine a position of the radio signal transmitter, wherein each set of information corresponds to a different relative position of at least one receiver to the transmitter, each set of information including radio signal data derived from radio signals received by the at least one receiver from the transmitter at each respective relative position, and positioning data containing information about a position of the at least one receiver at each respective relative position; and
means for assessing dynamics of a platform on which the radio signal transmitter is supported, and for correlating the different sets of information in a way dependent on the dynamics of the platform, wherein said means for assessing includes means for determining according to the type of radio signal whether the platform is a movable platform or a stationary, immovable platform.
15. An apparatus comprising non-transient media on which is stored computer readable code that, when loaded onto a computer, causes it to perform a method of determining a position of a radio signal transmitter, the method including:
determining a type of radio signal being transmitted from the radio signal transmitter by analyzing the radio signal for radio signal characteristics; and
correlating different sets of information in a way dependent on the determined radio signal type in order to determine the position of the radio signal transmitter;
wherein each set of information corresponds to a different relative position of at least one receiver to the transmitter, each set of information comprising:
radio signal data derived from radio signals received by the at least one receiver from the transmitter at each respective relative position: and
positioning data containing information about a position of the at least one receiver at each respective relative position, wherein the method further comprises:
assessing dynamics of a platform on which the radio signal transmitter is supported, and correlating the different sets of information in a way dependent on the dynamics of the platform, wherein said assessing includes determining according to the type of radio signal whether the platform is a movable platform or a stationary, immovable platform.
16. The method of claim 11 , wherein the Bayesian estimation filter includes at least one of a Kalman filter and a particle filter.