Implementation of a Space-borne Dual-frequency GPS RO FPGA Receiver with High-dynamic Bit Assist Acquisition

Kuan-Ying Huang ； Jyh-Ching Juang ； Mike Tsai ； Yung-Fu Tsai ； Chen-Tsung Lin

《Journal of Aeronautics, Astronautics and Aviation》 53卷3期 Vol.53 No.3 (2021/09) Pp. 429-439

https://doi.org/10.6125/JoAAA.202109_53(3).08

摘要

Radio occultation (RO) is a powerful satellite telemetry technique for providing vertical profiles of temperature and electron density of the ionosphere, which assures higher-value meteorological applications. In RO applications, receivers must collect dual-frequency Global Navigation Satellite System (GNSS) signals which pass through the atmosphere with different signal bending angles and modulate with their spreading code. Receiving secondary L2 signal by the satellite receiver is subject to the high mobility, fast channel parameter drift, longer L2 spreading code, and weak RO signals, therefore we implemented a GPS RO receiver with an adaptive channel link on the FPGA to perform high-dynamic aid acquisition to rapidly acquire the secondary GPS RO signal, achieving high-dynamic and weak signal detection, initializing its following tracking loop with a small loop initial error. To verify the scheme, a high-performance GNSS simulator was applied to generate the high-dynamic signal. Experiments at the seaside were performed to clarify the performance of receiving low-elevation RO signals from sea level.

關鍵字

Space-borne GPS RO receiver ； High-dynamic aided acquisition ； Weak GPS RO signal ； Implementation of RO receiver

參考文獻

Liu C, et al., “Characterisation of residual ionospheric errors in bending angles using GNS RO end-to-end simulations,” Advances in Space Research, Vol. 52, No. 5, 2013, pp. 821-836.

Sokolovskiy S, et al., “Use of the L2C signal for inversions of GPS radio occultation data in the neutral atmosphere,” GPS Solut, Vol. 18, No. 3, 2014, pp. 405-416.

Liu J, Chen SP, Yeh W, Tsai H, Rajesh P, “Worst- case GPS scintillations on the ground estimated from radio occultation observations of formosat- 3/cosmic during 2007–2014,” Surveys in Geophysics, Vol. 37, No. 4, 2016, pp. 791-809.

Qaisar SU and Dempster A, “Cross-correlation performance assessment of global positioning system (GPS) L1 and L2 civil codes for signal acquisition,” IET Radar Sonar Navig, 2011, pp. 195- 203.

Mao WL, Tsao HW, Chang FR, “Intelligent GPS receiver for robust carrier phase tracking in kinematic environments,” IET Radar, Sonar Navig., Vol. 151, 2004, pp. 171-180.