## 1 Introduction  
Hypersonic vehicles have radial relative movement with ground telemetry and communication stations during high-speed flight, which brings Doppler frequency offset to the received signals. Moreover, maneuvering the flight of hypersonic vehicles can produce a Doppler change rate. When hypersonic vehicles fly at the speed of 10-25 Mach in the Ka communication frequency band, the produced Doppler frequency offset reaches 453 kHz-1.133 MHz and the Doppler change rate is as high as 100 kHz/s. Large dynamic Doppler brings a huge challenge to existing telemetry and communication systems, which makes correct demodulation of communication information extremely difficult and thereby causes failure of tasks.  
The tracking speed in the traditional tracking loop is in contradiction with accuracy. Although the second-order phase-locked loop can accomplish accurate tracking of the Doppler frequency offset, it is inapplicable to the environment of large dynamic Doppler [1; 2]. To address easy unlocking at sudden change of Doppler frequency offset in the second-order phase-locked loop, [PERSON] [3] proposed an improved partial matched filtering (PMF)-FFT algorithm and a three-order phase-locked loop algorithm. [PERSON] [4] proposed an FFT loop algorithm assisted by time-domain partial matching PLL and FLL. These algorithms can relock tracking more quickly than the traditional second-orderphase-locked loop, but they still require secondary tracking upon unlocking fault, which prolongs telemetry and communication time to some extent. [PERSON] [5] introduced an Extended Kalman filter (EKF) to realize high dynamic tracking of GPS signals. EKF was composed of the third-order phase locked loop (PLL) assisted by frequency locked loop (FLL) and delay locked loop (DLL). Although EKF increased acquisition accuracy, it increased the structural complexity. [PERSON] [6] proposed a carrier tracking loop with high accuracy tracking performance based on Centerless Kalman filtering, which involved a feasible feedback way in the tracking loop so as to realize fast convergence of the algorithm and accurate tracking. This algorithm increased accuracy and stability at the cost of time. [PERSON] [7] put forward a single-peak searching range correction (SRC) algorithm with simple closed expression and corrected the searching range of subsequent periods based on multiple combined periods. Later, the acquisition probability was further increased by overlaying the SRC algorithm and iterative SRC algorithm based on overlying SRC algorithm, but the complexity was very high. In short, acquisition and tracking method cannot meet demands for accuracy and speed in a large dynamic Doppler, due to the contradictory relation between acquisition and tracking speed and accuracy.  
In this study, a telemetry and communication method based on the combination of Doppler diversity reception and fast coarse acquisition of Doppler frequency offset was proposed. The proposed method broke the above contradictions. Replacing accurate acquisition by coarse acquisition of Doppler frequency offset lowered the requirements on acquisition accuracy, thus saving acquisition time significantly. Replacing the real-time tracking of frequency and phase locked loop (FPLL) by Doppler diversity avoids unlocking fault caused by high complexity and dynamics variation of Doppler frequency offset in an ingenious way. The proposed method has flexible dynamic adjustment and it can adapt to the changing large dynamic Doppler environment.  
The remainder of this paper is organized as follows: Section 2 introduces the fast telemetry and communication method based on the Doppler diversity reception. Section 3 introduces the simulation results and conclusions under typical large dynamic Doppler scenario. Section 4 is the summary.