Method for resolving time ambiguity, a related system, a related transmitter and a related receiver

A method for resolving time ambiguity in a radio navigation satellite system between a radio transmitter (TX1) of a plurality of transmitters of said radio navigation satellite system having a first time scale and a radio receiver (RX1) of a plurality of radio receivers of said radio navigation satellite system having a second time scale, said radio transmitter (TX1) being coupled to said radio receiver (RX1), said radio transmitter transmitting a radio signal to said radio receiver (RX1), characterized in that said method comprising the steps of:

• generating, by said radio transmitter (TX1), an overlay sequence comprising a set of symbols per time ambiguity interval, said set of symbols having a predetermined length L, said overlay sequence satisfying a condition of single occurrence of a subset of symbols within said set of symbols of said time ambiguity interval, each said time ambiguity interval comprising an implicit time marker;
• and
• transmitting said radio signal, by said radio transmitter (TX1), to said radio receiver (RX1), said radio signal comprising said overlay sequence modulated onto a primary code, said primary code being modulated on a carrier of said radio signal;
• and
• receiving said radio signal by said radio receiver (RX1);
• and
• capturing a snapshot of said radio signal by said radio receiver (RX1), said snapshot comprising a subset of symbols of said overlay sequence comprising N symbols wherein a ratio of L/N being large as possible;
• and
• processing said snapshot, by said radio receiver (RX1), to determine a relative position of said implicit time marker of said radio signal based on the position of said subset of symbols included in said snapshot within said set of symbols of said time ambiguity interval;
• and
• resolving said Time Ambiguity between said first time scale and said second time scale by evaluating a delay between said implicit time marker expressed in said first time scale and based on said processing of said snapshot and said implicit time marker within said overlay sequence generated based on the second time scale wherein said overlay sequence consists of a M-ary sequence which is based on M-ary De Bruijn sequence.

A radio transmitter (TX1) configured to resolve time ambiguity in a radio navigation satellite system between said radio transmitter (TX1) of said radio navigation satellite system having a first time scale and a radio receiver (RX1) of said radio navigation satellite system having a second time scale, said radio transmitter (TX1) being configured to transmit a radio signal to said radio receiver (RX1), characterized in that said radio transmitter (TX1) comprising:

• a sequence generating means, configured to generate an overlay sequence comprising a set of symbols per time ambiguity interval, said set of symbols having a predetermined length L, said overlay sequence satisfying a condition of single occurrence of a subset of symbols within said set of symbols of said time ambiguity interval, each said time ambiguity interval comprising an implicit time marker;
• and
• a transmitting means, configured to transmit a radio signal to said radio receiver (RX1), said radio signal comprising said overlay sequence modulated onto a primary code, said primary code being modulated on a carrier of said radio signal, said overlay sequence comprising a set of symbols per time ambiguity interval, said set of symbols having a predetermined length L, each said time ambiguity interval comprising an implicit time marker, wherein said overlay sequence consists of a M-ary sequence which is based on a M-ary De Bruijn sequence.

A radio receiver (RX1) configured to resolve time ambiguity in a radio navigation satellite system between a radio transmitter (TX1) of said radio navigation satellite system having a first time scale and said radio receiver of said radio navigation satellite system having a second time scale, said radio transmitter (TX1) being configured to transmit a radio signal to said radio receiver (RX1), said radio signal comprising an overlay sequence satisfying a condition of single occurrence of a subset of symbols, modulated onto a primary code, said primary code being modulated on a carrier of said radio signal, said overlay sequence comprising a set of symbols per time ambiguity interval, said set of symbols having a predetermined length (L), each said time ambiguity interval comprising an implicit time marker, said radio receiver (RX1) further comprises:

• a reception means, configured to receive said radio signal;
• and
• a snapshot capture means, configured to take a snapshot of said radio signal, said snapshot comprising a subset of symbols of said overlay sequence, characterized in that said radio receiver further comprises:
• a processing means configured to determine a relative position of said implicit time marker of said radio signal based on the position of said subset of symbols of said overlay sequence included in said snapshot comprising N symbols wherein a ratio of L/N being large as possible;
• and in that
• said processing means further is configured to resolve said Time Ambiguity between said first time scale and said second time scale by evaluating a delay between said implicit time marker expressed in the first time scale and based on said processing of said snapshot and said implicit time marker within said overlay sequence generated based on said second time scale.