Abstract
The process of developing and certifying aircraft and aeronautical systems requires the execution of experimental flight test campaigns to determine the actual characteristics of the system being developed and/or validated. In this process, there are many campaigns that are inherently dangerous, such as the store separation. In this particular case, the greatest risk is the collision of the store with the fuselage of the aircraft. To mitigate the risks of this campaign, it is necessary to compare the actual trajectory of a separation with its simulated estimates. With such information, it is possible to decide whether the next store release can be done with the required safety and/or whether the model used to estimate the separation trajectory is valid or not. Consequently, exact determination of the trajectory of the separation is necessary. Store separation is a strategic, relevant, and complex process for all nations. The two main techniques for determining the quantitative store trajectory data with 6DoF (six degrees of freedom) are photogrammetry and instrumented telemetry packages (data obtained from inertial sensors that are installed in the store). Each presents advantages and disadvantages. In regard to photogrammetry, several market solutions can be used to perform these tests. However, the result of the separation trajectory is only obtained after the test flight, and therefore, it is not possible to safely carry out more than one on the same flight. In this context, the development and validation of a solution that will allow the realization of near real-time separation analysis are in fact an innovative and original work. This paper discusses the development and validation, through actual static ejection tests, of the components that will compose a new onboard optical trajectory system for use in store separation campaigns. This solution includes the implementation of a three-dimensional (3D) calibration field that allows calibration of the optical assembly with just one photo per optical assembly, development of a complete analytical model for camera calibration, and development of specific software for identification and tracking of targets in two-dimensional (2D) coordinate images and three-dimensional (3D) coordinate trajectory calculation. In relation to the calibration, the analytical model is based on a pinhole type camera and considers its intrinsic parameters. This allowed for a mean square error smaller than ±3.9 pixels @1σ. The 3D analysis software for 6DoF trajectory expression was developed using photogrammetry techniques and absolute orientation. The uncertainty associated with the position measurement of each of the markers varies from ±0.02 mm to ±8.00 mm @1σ, depending on the geometry of the viewing angles. The experiments were carried out at IPEV (Flight Test Research Institute)/Brazil, and the results were considered satisfactory. We advocate that the knowledge gained through this research contributes to the development of new methods that permit almost real-time analysis in store separation tests.
Highlights
Store separation is a strategic and complex process for all nations [1]
Store separation tests ensure that the stores released from an aircraft can safely pass through the aerodynamic disturbance of the aircraft without affecting the aircraft or other stores released simultaneously, which may cause damage to the aircraft or prematurely detonate the stores [11]
NATO [17] is focused on compatibility, integration, and store separation tests that have to be performed during the integration of an existing or newly developed store for military aircraft
Summary
Store separation is a strategic and complex process for all nations [1]. Aircraft-store separation is an old concept; the calculation of the store trajectory accuracy during the separation from an aircraft is more recent [2]. In the development of any type of store, the static ejection test ( known as pitch drop tests) is a fundamental part of the store separation campaign [3] These tests are performed to establish the aircraft and store configurations required for flight testing. There are two ways of determining the store trajectory data during the separation event, whether in flight or on the ground [5, 6], which are (1) photogrammetry using two or more fixed-orientation cameras (2) inertial navigation using sensors installed in the store (i.e., telemetry kit) Both methods present advantages and disadvantages [6,7,8]. The work carried out includes (1) the implementation of a three-dimensional (3D) visual field that will be used in the calibration of the optical assembly with only one photo (2) the development and validation of the complete analytical model to minimize the systematic distortions of the optical assembly (3) development and validation through static ejection tests of specific software for identification and tracking of targets in 2D images and for calculating the trajectory of 3D targets
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
