GPS Real Time Kinematic Software

SRI is a recognized leader in centimeter-level relative positioning GPS applications. Using a variety of proprietary techniques, SRI specializes in rapid reestimation of integer ambiguities that make robust centimeter-level accuracy possible in real time. This allows virtually seamless coverage of areas with poor GPS coverage, such as obstructed highways and banking aircraft.

Recent research has focused on fault isolation using multiple antennas and inertial navigation sensors for both airborne and vehicular applications. Recent clients include General Motors, BMW, California Partners for Advanced Transit and Highways (PATH), and the USAF. Some details of this work may be seen in the Winter 2003 edition of Navigation (see article).

SRI has constructed a number of programs for RTK (real time kinematic) L1/L2 carrier phase processing. Several of these programs have been used for highway applications where fast recovery from obstacles is one of the primary considerations. The programs can incorporate constraints such as altitude (available from highway maps). Some of these programs also use a two-receiver configuration to give high assurance that the integer solution is correct even for single epoch data. SRI has also created several programs for L1-only attitude systems, designed to work in applications where the sky is partially obstructed. There is also a multi-epoch program designed for L1-only carrier phase location on roadways.