A rear axle center (RAC) locating system may include a tractor and a RAC location acquisition unit. The tractor may include a rear axle having a center, a global positioning system (GPS) antenna offset from the rear axle, and inertial measurement units. The RAC location acquisition unit may include a processing unit and a non-transitory computer-readable medium containing instructions to direct the processing unit to determine a geographic location of the GPS antenna based upon signals received by the GPS antenna and determine a geographic location of the center of the rear axle based upon the geographic location of the GPS antenna and combined data from the inertial measurement units.

Techniques provided herein are directed toward virtually extending an updated set of output positions of a mobile device determined by a VIO by combining a current set of VIO output positions with one or more previous sets of VIO output positions in such a way that ensure all outputs positions among the various combined sets of output positions are consistent. The combined sets can be used for accurate position determination of the mobile device. Moreover, the position determination further may be based on GNSS measurements.

Techniques provided herein are directed toward virtually extending an updated set of output positions of a mobile device determined by a VIO by combining a current set of VIO output positions with one or more previous sets of VIO output positions in such a way that ensure all outputs positions among the various combined sets of output positions are consistent. The combined sets can be used for accurate position determination of the mobile device. Moreover, the position determination further may be based on GNSS measurements.

A multiple faulty global navigation satellite signal detecting system is provided. The system includes at least one pair of spaced antennas, at least one aiding source and processor. The at least one pair of spaced antennas are configured to receive satellite signals from a plurality of satellites. The at least one aiding source is used to generate aiding source position estimate signals. The processor is in communication with each antenna and the at least one aiding source. The processor is configured to determine signals blocks. The signal blocks being a collection of subsets of the determined difference signals and a covariance matrix for the difference signals. The processor further configured to generate a union of good signals from all the good blocks and a complementary set of bad signals.

A multiple faulty global navigation satellite signal detecting system is provided. The system includes at least one pair of spaced antennas, at least one aiding source and processor. The at least one pair of spaced antennas are configured to receive satellite signals from a plurality of satellites. The at least one aiding source is used to generate aiding source position estimate signals. The processor is in communication with each antenna and the at least one aiding source. The processor is configured to determine signals blocks. The signal blocks being a collection of subsets of the determined difference signals and a covariance matrix for the difference signals. The processor further configured to generate a union of good signals from all the good blocks and a complementary set of bad signals.

A method for planning a vehicle trajectory is provided. The method comprises obtaining an edge map representation corresponding to one or more terrain images of a given area, and identifying a total number of edge pixels in each of a plurality of sub-regions of the edge map representation. The method further comprises determining a measurement probability density function (PDF) for each of the sub-regions based on the number of edge pixels with information content in each sub-region. The method then computes a trajectory cost for each of the sub-regions by dividing a user-selected scalar by a sum of: a user-selected value and the number of edge pixels with information content in each sub-region. Thereafter, the method selects a trajectory for navigation of a vehicle over the given area based on the trajectory cost for each of the sub-regions.

A method for planning a vehicle trajectory is provided. The method comprises obtaining an edge map representation corresponding to one or more terrain images of a given area, and identifying a total number of edge pixels in each of a plurality of sub-regions of the edge map representation. The method further comprises determining a measurement probability density function (PDF) for each of the sub-regions based on the number of edge pixels with information content in each sub-region. The method then computes a trajectory cost for each of the sub-regions by dividing a user-selected scalar by a sum of: a user-selected value and the number of edge pixels with information content in each sub-region. Thereafter, the method selects a trajectory for navigation of a vehicle over the given area based on the trajectory cost for each of the sub-regions.

A tracking problem detection system for a machine may include tracking diagnostic circuitry including one or more tracking diagnostic processors configured to receive a location signal indicative of a location of a machine and a path signal indicative of a path location associated with at least a portion of a path for the machine to follow while maneuvering. The tracking diagnostic processors may also be configured to determine a tracking difference between the path location and the location of the machine, and determine a frequency of a signal associated with the tracking difference and/or a frequency of a signal associated with a yaw rate associated with the maneuvering. The tracking diagnostic processors may also be configured to detect, based at least in part on the frequencies of the signals associated with the tracking difference and/or the yaw rate, a tracking problem associated with maneuvering the machine.

A tracking problem detection system for a machine may include tracking diagnostic circuitry including one or more tracking diagnostic processors configured to receive a location signal indicative of a location of a machine and a path signal indicative of a path location associated with at least a portion of a path for the machine to follow while maneuvering. The tracking diagnostic processors may also be configured to determine a tracking difference between the path location and the location of the machine, and determine a frequency of a signal associated with the tracking difference and/or a frequency of a signal associated with a yaw rate associated with the maneuvering. The tracking diagnostic processors may also be configured to detect, based at least in part on the frequencies of the signals associated with the tracking difference and/or the yaw rate, a tracking problem associated with maneuvering the machine.

A system and method to distinguish spoofing signals from true GNSS signals is disclosed. One aspect of the present invention combines measuring GNSS carrier signals with measuring jitter in a vehicle's position via a low-cost inertial measurement unit (IMU) to distinguish spoofing signals from true GNSS signals. The present invention employs natural and/or artificial jitter of a vehicle, that, when combined with a tightly coupled inertial navigation system (INS), allows the receiver to distinguish the spoofing GNSS signal from the true GNSS signal. This spoofer survivability algorithm may be implemented, for example, in the software of a GNSS (or GPS) navigation system.