Hybrid Test Bench SINERGHYS "Statistical INERtial Gnss Hybrid in Simulation"

S. Gallot, P. Dutot, C. Sajous

Abstract:	The comprehensive assessment of military GPS receivers is becoming more and more complex as they are integrated into systems. To limit testing on systems in real conditions, laboratory evaluations with real elements are essential. This new assessment hardware in the loop tool is designed to automatic testing and to replay missions with an operational implementation and with a better control of initialization conditions especially direct P(Y) acquisition. This test bench drives many simulation tools: Spirent GPS/Galileo simulator, jamming means (Agilent generators, embedded jammer i.e. a digital miniaturized jammer), and different softwares like STK (Satellite Tool Kit - a software enabling the computation of visibility depending on the terrain modelling) or Ergospace (a software dedicated to the generation of multipaths on surfaces of realistic 3D scenes). The bench manages military GPS receivers input and output data as described in the respective receivers’ ICDs (Interface Control Document) or ISs (Interface Specification): this enables for example the initialization of GPS receivers by sending precise time (to facilitate direct P(Y) acquisition). This new bench is compatible with many GPS receivers with different form factors and applications. Several receivers can be tested at the same time with the same software so that the behavior of the GPS receivers can be compared in real time. Data from the different receivers can be observed on the same window of the GUI (Graphic User Interface). Specific data from ICDs can be displayed on the GUI. The user can visualize 3 different windows: the first is related to integrity, the second to alarms and the third to cryptography. All the data output by the receivers can be recorded and replayed. To facilitate and enhance trials on GPS receivers, the bench can use a Monte Carlo method, which enables sequentially and automatically chaining scenarios (up to 10 000 test sequences). It is primarily used for the characterization of TTFF (Time To First Fix). The methodology is described as follows: powering the receiver, randomizing errors of position, speed and time, then sending data to the GPS receiver and finally stopping the test sequence on chosen criteria. The user can select one or more criteria to stop the sequence (FOM, TFOM, state 5, protected status…). At the end, a synthetic file is provided with a statistical computing of the acquisition times (average, standard deviation, 2 sigma error…). The user can replay any particular observed case. Moreover, INS (Inertial Navigation System)/GPS (Global Positioning System) hybridization in real time can be simulated thanks to a processing based on a Kalman filter of the information delivered by simulated INS and GPS. Loose and tight coupling can be selected through the GUI as well as the parameters of the filter. The Kalman filter design is independent from the receiver and from the type of trajectory simulated. The user can decide whether the GPS receiver does receive aiding either from the simulated INS, or from the optimal navigation (output of Kalman filter).
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1975 - 1981
Cite this article:	Gallot, S., Dutot, P., Sajous, C., "Hybrid Test Bench SINERGHYS "Statistical INERtial Gnss Hybrid in Simulation"," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1975-1981.
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