GPS/INS

About: GPS/INS is a research topic. Over the lifetime, 3554 publications have been published within this topic receiving 62784 citations.

Location of radio frequency emitting targets

Abstract: A method is described which enables the location of a radio frequency emitting target in absolute or relative GPS coordinates from a single airborne platform within a few seconds. The method uses a signal processing technique which emulates an antenna moving at very high velocities to induce a Virtual Doppler shift on signals incident upon a linear antenna array. The Virtual Doppler shift is directly proportional to the signal direction of arrival as measured by its direction cosine. The method is shown to prevent single and multiple GPS jammers from being able to jam conventional GPS signals. Also disclosed is a means and method for developing virtual Doppler shifted signals to determine the angle-angle bearing of emitting targets to high resolution. This in turn, allows the position of the emitter to be determined in a GPS reference frame to be located to a high degree of accuracy from a single platform in extremely short times. The ultra-high precision direction-find capability requires the ability to determine the direction cosines of GPS satellite signals incident upon the detecting air vehicle and provides GPS anti-jam capability as a derivative of the definition of the direction finding.

Rapid development of tightly-coupled GPS/INS systems

Abstract: This paper addresses the question: "Why aren't tightly-coupled OPS/INS systems everywhere, on aircraft, ships and land vehicles?" Two barriers to the widespread use are cited. One is the high cost of the INS, and the other is the cost and complexity of tightly-coupled OPS/INS integration. One of those two barriers has recently been diminished drastically with the development of a standardized software package for tightly-coupled integration. In the past, only the largest corporations have been able to pay the initial development cost for tightly-coupled OPS/INS integration, usually with funding from a large defense program. Using the new software package, integration and van test can be accomplished in a matter of days, and this has been demonstrated with field trials. The package is intended primarily for small companies that otherwise would not be able to build tightly-coupled OPS/INS systems at all. What would have been a prohibitive 3- or 4-man year development effort is reduced to a few man weeks. To accomplish an integration, the system integrator has to find a way, through serial interfaces or by some other means, to get the INS measurements of acceleration (accumulated velocity change /spl Delta/V) and attitude rate (accumulated angle change /spl Delta//spl theta/) into a processor, along with the raw data of a GPS receiver. He also has to find a way to time tag the INS /spl Delta/V, /spl Delta//spl theta/ with GPS time. The rest of tightly-coupled OPS/INS integration is predominately accomplished in the standardized software package. That leaves the cost of the INS as the only remaining barrier to the very widespread use of OPS/INS, and invites new development of low cost inertial sensors. The focus of this paper is on the software package, and how it achieves standardization and ease of use while retaining the flexibility to produce optimal results with a variety of INS and GPS receiver types.

Inertial pointing and positioning system

Abstract: An inertial pointing and control system and method for pointing to a designated target with known coordinates from a platform, to provide accurate position, steering, and command information The system continuously receives GPS signals and corrects Inertial Navigation System (INS) dead reckoning or drift errors An INS is mounted directly on a pointing instrument rather than in a remote location on the platform for monitoring the terrestrial position and instrument attitude, and for pointing the instrument at designated celestial targets or ground based landmarks As a result, the pointing instrument and the INS move independently in inertial space from the platform since the INS is decoupled from the platform Another important characteristic of the present system is that selected INS measurements are combined with predefined coordinate transformation equations and control logic algorithms under computer control in order to generate inertial pointing commands to the pointing instrument More specifically, the computer calculates the desired instrument angles (Phi, Theta, Psi), which are then compared to the Euler angles measured by the instrument-mounted INS, and forms the pointing command error angles as a result of the compared difference

A Novel INS and Doppler Sensors Calibration Method for Long Range Underwater Vehicle Navigation

Abstract: Since the drifts of Inertial Navigation System (INS) solutions are inevitable and also grow over time, a Doppler Velocity Log (DVL) is used to aid the INS to restrain its error growth. Therefore, INS/DVL integration is a common approach for Autonomous Underwater Vehicle (AUV) navigation. The parameters including the scale factor of DVL and misalignments between INS and DVL are key factors which limit the accuracy of the INS/DVL integration. In this paper, a novel parameter calibration method is proposed. An iterative implementation of the method is designed to reduce the error caused by INS initial alignment. Furthermore, a simplified INS/DVL integration scheme is employed. The proposed method is evaluated with both river trial and sea trial data sets. Using 0.03°/h(1σ) ring laser gyroscopes, 5 × 10−5 g(1σ) quartz accelerometers and DVL with accuracy 0.5% V ± 0.5 cm/s, INS/DVL integrated navigation can reach an accuracy of about 1‰ of distance travelled (CEP) in a river trial and 2‰ of distance travelled (CEP) in a sea trial.

SLAM aided GPS/INS Navigation in GPS Denied and Unknown Environments

Abstract: This paper presents the results of augmenting a GPS/INS navigation system with a Simultaneous Localisation and Mapping (SLAM). SLAM algorithm is a landmark based terrain aided navigation system that has the capability for online map building, and simultaneously utilising the generated map to bound the errors in the Inertial Navigation System (INS). Due to the low quality of the inertial sensors used, even a short-term GPS dropout can degrade the inertial navigation performance significantly, which can affect the vehicle safety as well. In addition, in GPS denied environments, most navigation systems need a separate aiding source in order to increase the reliability and availability. In this paper, SLAM is augmented to GPS/INS system, which can provide information about the states of a vehicle without the need for a priori infrastructure such as GPS, ground beacons, or a preloaded map. If GPS information is available, the SLAM integrated system builds a landmark-based map using a GPS/INS solution. If GPS is not available, the previously and/or newly generated map is used to constrain the INS errors. Simulation results will be presented which shows that the system can provide reliable and accurate navigation/landmark-map solutions even in a GPS denied and/or unknown environments.