Systems and methods according to the present invention describe 3D pointing devices which enhance usability by transforming sensed motion data from a first frame of reference (e.g., the body of the 3D pointing device) into a second frame of reference (e.g., a user's frame of reference). One exemplary embodiment of the present invention removes effects associated with a tilt orientation in which the 3D pointing device is held by a user.

3D pointing devices with orientation compensation and improved usability

The invention comprises a method of determining an orientation of a sensor, includes measuring a local magnetic field vector (507) and a local gravity vector (509) and using those measurements to determine the orientation of the sensor. Another embodiment comprises measuring a local magnetic field vector (507), a local gravity vector (509), and the angular velocity of the sensor (501). These three vectors are processed to determine the orientation of the sensor. Another embodiment comprises determining a local gravity vector (509) by providing an acceleration detector, moving the detector from a start point to an end point over a time period, and summing acceleration measurements over the time period. The total gravity vector is calculated using the summed acceleration measurements.

Method and apparatus for motion tracking of an articulated rigid body

Systems and methods according to the present invention address these needs and others by providing a handheld device, e.g., a 3D pointing device, which uses at least one sensor to detect motion of the handheld device. The detected motion can then be mapped into a desired output, e.g., cursor movement.

3D pointing devices and methods

An activity monitor, comprises housing for attachment to a person; at least one accelerometer disposed within the housing; and a processor disposed within the housing, for processing signals from the accelerometer to assess activity of the person. A method assesses activity of a person, including: sensing acceleration at a first location on the person; processing the acceleration, over time, to assess activity of the person; and wirelessly communicating information indicative of the activity to a second location.

Activity monitoring systems and methods

A personal items network, comprising a plurality of items, each item having a wireless communications port for coupling in network with every other item, each item having a processor for determining if any other item in the network is no longer linked to the item, each item having an indicator for informing a user that an item has left the network, wherein a user may locate lost items. A method for locating lost personal items, comprising: linking at least two personal items together on a network; and depositing one or both of time and location information in an unlost item when one of the items is lost out of network.

Personal items network, and associated methods

A navigation system for spinning projectiles using a magnetic spin sensor to measure the projectile roll angle by sensing changes in magnetic flux as the projectile rotates through the earth's magnetic field is disclosed. The magnetic spin sensor measurements are used to despin a body reference frame such that position, velocity, and attitude of the projectile can be determined by using a strapdown inertial navigation system (INS) algorithm. More particularly, a multisensor concept is used to measure pitch and yaw angular rates, by measuring Coriolis acceleration along the roll axis and demodulating the pitch and yaw rates therefrom.

Navigation system for spinning projectiles

Disclosed is a GPS pseudolite transmitter, receiver and navigation system. The GPS pseudolite transmitter is adapted to transmit a first phase modulated L-band signal at a first signal pulse repetition rate having an associated first period time duration. The first phase modulated L-band signal is modulated with a short period code having a code epoch of at least about one millisecond. For each consecutive transmission pulse having the first period time duration, the pseudolite transmitter transmits the first phase modulated L-band signal during less than one half of the first period time duration, and for at least about 1 millisecond so that the first pseudolite transmitter transmits an epoch of the short period code during each transmission pulse. A receiver is adapted to receive the first phase modulated L-band signal from the first pseudolite transmitter, at times when it is not integrating phase modulated L-band signals from other GPS pseudolites transmitters, such that cross-correlation with other phase modulated L-band signals is minimized. Furthermore, the receiver is adapted to receive the L-band satellite signal during intervals when no pseudolite signals are being received.

GPS pseudolite and receiver system using high anti-jam pseudolite signal structure

Disclosed is a method which synchronizes a slave time with a master time. The master time is derived from a received signal. The master time is compared to the slave time to detect any offset of the slave time relative to the master time. If an offset is detected, the slave time is adjusted to correct the offset. Also disclosed is a method of synchronizing a pseudolite transmitter time with GNSS time. The transmitter time is compared to GNSS time to detect any offset of the transmitter time. The transmitter time is adjusted to correct the offset if an offset is detected. Also disclosed is an improved pseudolite. The pseudolite has a pseudolite transmitter and GNSS receiver. The pseudolite transmitter time is synchronized with GNSS time.

Wilmer A. Mickelson

Papers

Navigation system for spinning projectiles

GPS pseudolite and receiver system using high anti-jam pseudolite signal structure

Method and means for precise time synchronization