Beidou satellite-based initial train positioning calculation method and positioning system

A satellite positioning system, comprising:

• a vehicle-mounted subsystem comprising:
• a first navigation receiver being capable of receiving the satellite signal and obtain the track electronic map file;
• at least one processor;
• and
• a memory coupled to the at least one processor to store instructions, which when executed by the at least one processor, cause the satellite positioning system to perform operations, the operations comprising:
• based on the navigation data and the track electronic map file, selecting one or more track sections of a current position of a train as candidate track sections, and putting each of the candidate track sections into a set TrackList;
• determining whether a number of the candidate track sections in the set TrackList is 1;
• according to the determination result, selecting a single track position comparison algorithm or a non-single track position comparison algorithm to execute to determine an initial train position of the train;
• and
• controlling the train to operate according to the initial train position,
• wherein the non-single track position comparison algorithm comprises:
• performing initialization, and taking out all the track sections of the TrackList and respectively denoting the track sections as T1, T2, . . . , Tn, a variable x=1;
• obtaining current navigation data, performing a map matching algorithm on the current navigation data and each of the track sections T1, T2, . . . Tn, and according to the map matching result, generating a track-based one-dimensional train position MTLx comprising a station number, a track number and a parallel track offset;
• determining whether the MTLx is valid or not;
• determining whether {MTL1, . . . MTLn} has only a unique valid value:
• in response to {MTL1, . . . MTLn} does not have only a unique valid value, exiting;
• and
• initializing the unique valid one-dimensional train position as the initial train position, such that the initial train position is determined successfully.

A non-transitory machine-readable medium having instructions stored therein, which when executed by at least one processor, cause the at least one processor to perform operations, the operations including:

• receiving satellite signals to obtain navigation data;
• obtaining a track electronic map file;
• based on the navigation data and the track electronic map file, selecting one or more track sections of a current position of the train as candidate track sections, and putting each of the candidate track sections into a set TrackList;
• determining whether a number of the candidate track sections in the set TrackList is 1;
• according to the determination result, selecting a single track position comparison algorithm or a non-single track position comparison algorithm to execute to determine an initial train position of the train;
• and
• controlling the train to operate according to the initial train position,
• wherein the non-single track position comparison algorithm comprises:
• performing initialization, and taking out all the track sections of the TrackList and respectively denoting the track sections as T1, T2, . . . , Tn, a variable x=1;
• obtaining current navigation data, performing a map matching algorithm on the current navigation data and each of the track sections T1, T2, . . . Tn, and according to the map matching result, generating a track-based one-dimensional train position MTLx comprising a station number, a track number and a parallel track offset;
• determining whether the MTLx is valid or not;
• determining whether {MTL1, . . . , MTLn} has only a unique valid value:
• in response to {MTL1, . . . , MTLn} does not have only a unique valid value, exiting;
• and
• initializing the unique valid one-dimensional train position as the initial train position, such that the initial train position is determined successfully.