GPS tracking system
First Claim
1. A tracking system employing global positioning system (GPS) satellites for determining the position of one or more objects to be tracked, the tracking system comprising:
- sensor means, mounted on each object, for receiving signals provided by a plurality of visible GPS satellites and for recording and buffering sensor data, comprising raw satellite signals that are periodically sampled over a predetermined time window;
workstation means for receiving and storing said sensor data, for processing said sensor data to compute pseudo-range and delta-range data for periodically computing, from said pseudo-range and delta-range data, position and velocity information relative to the one or more objects, and for displaying the computed position and velocity information to an operator at a central location, said workstation means further comprising a GPS reference receiver for providing aiding data to facilitate searching, acquiring, and tracking said raw satellite signals received by said sensor means; and
a data telemetry link coupling said sensor means and said workstation means, for transferring the recorded and buffered sensor data from said sensor means to said workstation means at a transfer rate that is lower than a rate at which said raw satellite signals were sampled by said sensor means.
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Accused Products
Abstract
A low cost tracking system employing satellites of the global positioning system (GPS) is suitable for applications involving radiosondes, sonobuoys, and other objects. The tracking system includes a sensor mounted on each object which digitally samples the GPS satellite signals and records them in a data buffer. The digital samples are then transmitted, at a rate lower than that at which the GPS satellite signals were sampled, over a data telemetry link, interleaved with other telemetry data from the object. The GPS data is processed in a data processing workstation where the position and velocity of the sensor, at the time the data was sampled, is computed. The data buffer in the sensor is periodically refreshed, and the workstation periodically computes the new position and velocity of the sensor. Differential corrections are also provided at the workstation to aid in signal acquisition and to increase the precision of the position fix.
517 Citations
7 Claims
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1. A tracking system employing global positioning system (GPS) satellites for determining the position of one or more objects to be tracked, the tracking system comprising:
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sensor means, mounted on each object, for receiving signals provided by a plurality of visible GPS satellites and for recording and buffering sensor data, comprising raw satellite signals that are periodically sampled over a predetermined time window; workstation means for receiving and storing said sensor data, for processing said sensor data to compute pseudo-range and delta-range data for periodically computing, from said pseudo-range and delta-range data, position and velocity information relative to the one or more objects, and for displaying the computed position and velocity information to an operator at a central location, said workstation means further comprising a GPS reference receiver for providing aiding data to facilitate searching, acquiring, and tracking said raw satellite signals received by said sensor means; and a data telemetry link coupling said sensor means and said workstation means, for transferring the recorded and buffered sensor data from said sensor means to said workstation means at a transfer rate that is lower than a rate at which said raw satellite signals were sampled by said sensor means. - View Dependent Claims (2)
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3. A tracking process employing global positioning system (GPS) satellites for determining the position and velocity of each of one or more objects to be tracked, the process comprising:
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mounting a sensor on each object; receiving raw satellite signals at the sensor provided by a plurality of GPS satellites visible to the sensor; periodically sampling said raw satellite signals over a predetermined time window to form sensor data; recording and buffering said sensor data within the sensor; transmitting said recorded and buffered sensor data over a data telemetry link at a transmission rate that is lower than a rate at which said raw satellite signals were sampled; providing a centrally-located GPS workstation for receiving the transmitted sensor data; providing a GPS data processor within said GPS workstation for processing said recorded and buffered sensor data to compute GPS pseudo-range and delta-range measurements during the time window in which the raw satellite signals were sampled; providing a GPS reference receiver within said GPS workstation for generating aiding data to facilitate searching, acquiring, and tracking said raw satellite signals received by said sensor; and processing the computed GPS pseudo-range and delta-range measurements in said centrally-located GPS workstation to compute the position and velocity of said one or more objects during the time window in which the received raw satellite signals were sampled. - View Dependent Claims (4, 5, 6, 7)
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Specification