Abstract: Due to the public disclosure of civil navigation signals, they are susceptible to malicious deception and interference. Once the timing system of the power industry is deceived, the national power system will find it difficult to operate normally. In response to the current situation of malicious deception faced by the BeiDou navigation system and the high complexity of existing anti deception detection technologies that are difficult to widely apply, this paper establishes a binary hypothesis test and proposes time difference and inter satellite difference deception detection methods based on carrier to noise ratio. As the carrier to noise ratio of deception signals is generally higher than that of real signals, this paper uses time difference to determine whether the carrier to noise ratio of satellite signals has abnormal changes, in order to detect high-power deception signals. In addition, since the carrier to noise ratio of deception signals transmitted by a single antenna is the same, while there are differences in the inter satellite carrier to noise ratio of real BeiDou satellite signals, this paper uses the carrier to noise ratio difference between different satellite signals as zero to detect the existence of deception signals transmitted by the same deception source. By processing and analyzing the data collected from the experimental platform, the time difference and inter satellite difference deception detection algorithms based on carrier to noise ratio were successfully validated.