Flight Test of New Integrated Navigation System (NINS) and New Integrated Landing System (NILS)

Henrik Eriksson, Systems and Flight Test, Saab Aerospace, Linköping, Sweden
Bengt Wall, Systems and Flight Test, Saab Aerospace, Linköping, Sweden

Abstract

The Swedish multirole aircraft JAS 39 Gripen will be equipped with a New Integrated Navigation System (NINS) and a New Integrated Landing System (NILS). NINS/NILS uses on-board sensors (RALT, ADC and INS) combined with terrain data stored in the systems computer. The system will make the aircraft independent of ground based navigation and landing aids.

Test and verification of earlier navigation and landingsystems have required a huge number of flights. To reduce the number of flights and costs, two simulators have been developed, NSM and NINS-SIM. Flight tests, simulators and sensor models have been used in parallel during both development and verification of the system. Without this methodology the development and verification would demand a huge number of flights and modification of the algorithms between the flights.

In flight test an extensive amount of data is recorded. Already from the beginning sensor data from flights have been used in the development of the algorithms in NINS/NILS. The quality of the data recorded and the ability to timetag them is of great importance in this project. This has made it possible to verify the algorithms and to ensure proper function of the system before first flight.

NINS-SIM is a computer in the loop environment with the systems computer in which NINS executes. NINS-SIM contains functionality to supply the systems computer with prerecorded flight data or simulated sensor data via 1553 data bus. NINS-sim also contains a timing mechanism that makes it possible to compare navigation performance with DGPS measurements from the actual flight.

NSM is a pure software simulation environment for NINS. It is possible to use either prerecorded flight data or a mission file in NSM. In a mission file waypoints and events are specified. When a mission file is used sensor data is generated from sensor models. These models ca be controlled and errors can be added to sensor data. The huge amount of data recorded during flight tests enables a thorough analysis of NINS/NILS performance. Data from flight tests are compared with DGPS measurements. During flight tests the pilots also evaluate the performance of NINS/NILS.

This paper describes the tools and methods used to develop and verify NINS and NILS.