| The navigation receiver with spread spectrum (SS) technique is a crucial equipment of the radio navigation system. Carrier synchronization, observed quantity extraction and navigation computation, the key techniques of the receiver, determine the receiver to work normally or not, and affect the receiver performance deeply. This paper focuses on these techniques in the navigation receiver by use of medium short wave.Carrier was tracked steadily is the premise of range measurement and positioning. Carrier synchronization is implemented by a kind of closed loop with degenerative feedback. Frequency tracking and phase tracking are two different classes of carrier tracking loop. On the basis of researching the relation of tracking performance and phase discrimination characteristic, we can conclude that frequency tracking loop and phase tracking loop should adopt Signed Cross-Product Automatic Frequency Control loop and Costas loop with arc tangent discriminator. And combining two loops may fill the purpose to adapt the dynamic of receiver and improve the precise of tracking. After the relation of the tracking threshold and the tracking error is analyzed, the method to figure out the bandwidth of tracking loop is presented and the loop filter is designed.Observed quantity extraction technique and navigation computation algorithm affect the receiver's positioning precise in a large degree. Observed quantity can be conversed by the output of loop filter, and the expressions are derived. Integer ambiguity is a key problem of carrier phase range measurement, and any error will lead to large worsening of positioning precise. After referring to many literatures, this paper designed a new algorithm which uses two receivers, observed quantity minus each other twice, combine pseudo random noise code and carrier phase information and adopt LAMBDA algorithm to search ambiguity. This algorithm is verified by a series of followed simulations.
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