Abstract: As the mine production process becomes increasingly unmanned / less humanization, the pose recognition technology of mining equipment is of great significance to the safe production of coal mine and machine cooperation. In order to solve the problems of dense multipath and large phase errors caused by the frequency reflection and scattering of electromagnetic waves in a complex driving environment with limited space,an anti-interference model based on nonlinear second-harmonic backscattering is established using the passive broadband harmonic tag which is used to generate an available harmonic signal,realizing the frequency diversity of uplink and downlink to suppress dense mul- tipath interference of the mine. Using the geometric positioning method based on distance,a Coherent Sending broad- band Multifrequency Continuous-wave (CSMCW) phase difference ranging algorithm is proposed to solve the problems of accuracy in ranging,positioning and recognition under the condition of large phase error. Taking the roadheader as an example,the passive pose recognition method of a roadheader based on CSMCW phase difference ranging is stud- ied. In order to verify the feasibility of the above theory and algorithm,a simulation experimental scene of a roadheader with a length,width,and height of 105 m×4 m×3 m was established,and the anti-interference performance of the har- monic tags,CSMCW phase difference ranging,and the pose recognition effect of the roadheader were simulated. Simu- lation results show that compared with traditional passive tags,using passive broadband harmonic tags can obtain a lar- ger signal-to-interference ratio,which has stronger robustness and can effectively suppress nanosecond dense multipath interference. Compared with the quadratic phase difference ranging algorithm and the staggered frequency difference ranging algorithm,the CSMCW ranging algorithm based on the harmonic backscattering anti-interference model is more robust,and the positioning range can reach the centimeter resolution under the condition of low signal-to-noise ratio, which ensures the attitude angle recognition of a roadheader. When the SNR = -5 dB and the measurement distance is 100 m,the maximum error of the heading angle,pitch angle and roll angle of the roadheader is about 2. 3° based on the proposed multifrequency continuous-wave phase-difference ranging method for the pose recognition of a roadhead- er,which can meet future applications.