Method for collecting GPS almanac

The invention discloses a GPS almanac collection method, which comprises the following steps: judging whether obtained data is fourth or fifth subframe data, and controlling the operation of a collection program according to a result; judging the validity of word data in the obtained sub-frame data and whether toa data of almanac is contained in the word data or not; if the currently obtained word data is effective and contains the toa data, extracting the toa data sent by each satellite, comparing the toa data with the toa data, and determining whether almanac data updating needs to be carried out or not; according to the stored toa data, finding out satellite data channels for sending the same toa data, and marking the satellite data channels; integrating the marked satellite data channels, and receiving the data of the marked satellite data channels until the whole subframe data is obtained; and repeating the steps to collect data of all satellites, and obtaining complete almanac data. According to the sch