A receiver, comprising a board device comprising a signal acquisition device, the signal acquisition device comprising:
- a satellite signal transmitting time estimation module, performing the operation of estimating a satellite signal transmitting time comprising:
- acquiring a receiver time, estimating an error of the receiver time to generate an estimated value of receiver time, obtaining an estimated value of the satellite signal travel time, and determining an estimated value and an error range of the satellite signal transmitting time according to the estimated value of the receiver time and the estimated value of the satellite signal travel time;
- a code phase search interval determination module, performing the operation of determining a code phase search interval comprising:
- based on an estimated value of the satellite signal transmitting time, the error range of the satellite signal transmitting time and navigation message structure, estimating a frame header start time tt_sf_x and its error range ±tt_err, thereby determining tt_sf_x−tt_err to tt_sf_x+tt_err as the code phase search interval, dividing the code phase search interval into K code phase search subintervals mk, wherein, x represents a sub-frame number and is an integer greater than 0, K is an integer greater than or equal to 1, and k represents a sequence number of the code phase search subinterval, k is an integer, 1≤k≤K, the time length of the code phase search subinterval mk is tmk milliseconds, and the sum of the time lengths of K code phase search subintervals is greater than or equal to the double of the value of the error range tt_err;
- and
- a search module, performing search operations, the search module comprising a data acquisition control module and an acquisition processing and determination module,
- wherein the data acquisition control module performs data acquisition control operations comprising:
- acquiring the intermediate frequency data starting from data acquisition time, the acquired intermediate frequency data has a final length of tmk+tn milliseconds, and acquiring PN code corresponding to the frame header start time tt_sf_x, the acquired PN code has a final length of tn milliseconds, wherein the estimated frame header start time tt_sf_x plus the corresponding time offset dk can be used as the data acquisition time, and the value of tn does not exceed the length of the first two words in each sub-frame of the navigation message;
- and the acquisition processing and determination module performing the acquisition processing and determination operations:
- for a certain Doppler frequency point, at any time during the period from the data acquisition time to the end of data acquisition, performing an acquisition processing operation on the acquired intermediate frequency data and PN code, and comparing the result of the acquisition processing with a preset threshold to perform a determination operation, wherein, the acquisition processing includes correlation operation processing, navigation message peeling processing, and fast Fourier transform processing.