Expanding the region of convergence for SITAN through improved modelling of terrain nonlinearities

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6165551

Hostetler, L D; Beckmann, R C

The SITAN (Sandia Inertial Terrain-Aided Navigation) system was originally developed to provide continuous updating of an inertial navigation system by using radar altimeter measurements of the terrain in conjunction with prestored topographic data in an extended Kalman filter. The basic algorithm performs satisfactorily for limited initial position uncertainties, but can diverge when the position uncertainty is so great that terrain linearity assumptions are significantly violated. An improvement to the basic system is described which considerably increases the region of convergence. The improvement is accomplished by modelling the terrain nonlinearities as Gauss-Markov measurement noise whose statistics and frequency content are adaptively varied as the uncertainty region evolves with time. Theoretical development of this modification is given and results of flight test experiments are presented which verify the ability of this modification to significantly increase SITAN's region of convergence.

• Research Organization: Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 6165551
• Report Number(s): SAND-78-2350C; CONF-790525-2
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420200* -- Engineering-- Facilities
Equipment
& Techniques
AIRCRAFT
MEASURING INSTRUMENTS
MODIFICATIONS
NAVIGATIONAL INSTRUMENTS
OPTIMIZATION
RADAR
RANGE FINDERS
SPACE VEHICLES
TOPOGRAPHY