Method for resolving sub-carrier ambiguities of a number of tracking channels of a navigation signal

A method for resolving sub-carrier ambiguities of a total number of tracking channels of a binary offset carrier (BOC) navigation signal comprising a carrier modulated by a code modulation function of a given code rate and further modulated by a sub-carrier modulation function of a given sub-carrier rate, for each channel comprising:

• generating a first estimate τ of delay based on the code modulation;
• generating a second estimate τ* of delay based on the sub-carrier modulation,
• wherein for a simultaneously considered subset of at least four tracking channels, the method further comprises
• determining a set of sub-carrier candidate ambiguities Ni,k based on the sub-carrier modulation by processing the first and the second estimate of delay by calculating
• N
• i
• ,
• k
• =
• round
• ⁢
• ⁢
• (
• τ
• i
• -
• τ
• i
• *
• T
• s
• )
• +
• k
• ·
• T
• s
• with i being a channel, k being the ambiguities, and Ts being a sub-carrier chip duration;
• calculating, for each possible combination of the sub-carrier candidate ambiguities, position error and receiver clock error;
• calculating predicted delays based on each of the calculated position error and receiver clock error;
• calculating differences between the predicted delays and delay candidates, wherein each of the delay candidates is based on a sub-carrier candidate ambiguity, of the set of sub-carrier candidate ambiguities, for a respective tracking channel;
• calculating a residual for a specific combination of sub-carrier ambiguities based on the calculated differences by squaring and summing the differences between the predicted delays and the delay candidates, providing the residual for the specific combination of sub-carrier ambiguities;
• selecting a set of sub-carrier ambiguities and corresponding position error and receiver clock error leading to the smallest residual;
• and
• determining a position of a GNSS receiver corresponding to the position error and receiver clock error.