In the field of land integrated navigation, a laser Doppler velocimeter (LDV) can be used as a speed sensor to compose an integrated navigation system with a strapdown inertial navigation system (SINS). To suppress the influence of the inclination variations caused by vehicle jolts on conventional LDVs, a split-reuse LDV based on Janus configuration was presented. Aiming at the error parameters of this configuration type LDV in the integrated navigation with SINS, the velocity error model of LDV was deduced first, and then a Kalman filtering method assisted by a differential global positioning system (DGPS) to calibrate the error parameters was proposed. A simulation and a vehicle integrated navigation experiment were implemented to verify the effectiveness of the method. The experimental results show that the calibration method proposed in this paper is effective. The LDV based on Janus configuration after being compensated can greatly improve the positioning accuracy of the integrated navigation system.