Global Positioning System Sensor with Instantaneous-Impact-Point Prediction for Sounding Rockets

Abstract

The development and verification of a dedicated global positioning system (GPS) sensor for sounding rocket missions is described. It is based on the hardware design of a terrestrial low-cost, single-frequency coarse/acquisition (C/A) code receiver but operates an enhanced software that has been specifically adapted for high dynamics applications. Besides the navigation and timing function provided by traditional GPS receivers, the prediction of the instantaneous impact point (IIP) has for the first time been integrated into the receiver software. Making use of a newly developed perturbed-parabolic trajectory model, the receiver can directly perform real-time IIP predictions with an accuracy that is compatible with operational ground software and is only limited by atmospheric forces. It is expected that the availability of onboard IIP prediction will both simplify existing range safety systems and contribute to a future increase of the onboard autonomy of sounding rocket missions. The overall receiver performance is demonstrated with hardware-in-the-loop simulations and actual flight data for representative mission profiles.