The strategic position of the polar area and its rich natural resources are becoming increasingly important, while the northeast and northwest passages through the Arctic are receiving much attention as glaciers continue to melt. The global navigation satellite system (GNSS) can provide real-time observation data for the polar areas, but may suffer low elevation problems of satellites, signals with poor carrier-power-to-noise-density ratio (C/N 0 ), ionospheric scintillations, and dynamic requirements. In order to improve the navigation performance in polar areas, a deep-coupled navigation system with dual-frequency GNSS and a grid strapdown inertial navigation system (SINS) is proposed in the paper. The coverage and visibility of the GNSS constellation in polar areas are briefly reviewed firstly. Then, the joint dual-frequency vector tracking architecture of GNSS is designed with the aid of grid SINS information, which can optimize the tracking band, sharing tracking information to aid weak signal channels with strong signal channels and meet the dynamic requirement to improve the accuracy and robustness of the system. Besides this, the ionosphere-free combination of global positioning system (GPS) L1 C/A and L2 signals is used in the proposed system to further reduce ionospheric influence. Finally, the performance of the system is tested using a hardware simulator and semiphysical experiments. Experimental results indicate that the proposed system can obtain a better navigation accuracy and robust performance in polar areas. of meridian convergence by setting an available reference line. However, the single SINS navigation output still contains periodic oscillation errors and accumulated errors.The global navigation satellite system (GNSS) can provide real-time observation data globally and in all weather [8,9]. Besides this, more and more GNSS frequency bands are available for users, which will benefit from the development of dual-frequency or multifrequency receivers [10][11][12]. However, in polar areas, GNSS signals often suffer low elevation problems of satellites, signals with poor carrier-power-to-noise-density ratio (C/N 0 ), ionospheric scintillations, and even dynamic requirements, which may cause the navigation performance to decline and even fail [13,14].The above discussion indicates that it is hard for a single navigation system to provide precise and reliable navigation information in polar areas. On the contrary, the integrated navigation system is a popular solution for many applications which need a precise and reliable navigation output. Some grid-SINS-based integrated systems with the star tracker [6] and Doppler velocity logger (DVL) [7,15] have been designed, but they have limits of application such as weather conditions or underwater/shipping applications only. Although a loose-coupled GNSS/grid SINS is proposed in [16], neither the coverage and usability of satellites, the quality of GNSS signals, nor the dynamic requirements have been considered, which may greatly affect the navigation ...