Apparatus and method for determining velocity of a platform
First Claim
1. An apparatus for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising:
- a GPS receiver located at the platform for receiving a plurality of GPS signals from a corresponding plurality of GPS satellites and outputting GPS navigation data;
an inertial measurement unit located at the platform for outputting inertial navigation data indicative of the inertial movement of the platform;
a processor for generating an acceleration signal indicative of the acceleration of the platform by combining a first acceleration measurement of the platform calculated from the GPS navigation data with a second acceleration measurement of the platform calculated from the inertial navigation data; and
said processor further generating the velocity signal from the acceleration signal and the GPS navigation data.
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Abstract
An apparatus and method for determining the velocity of a platform includes a GPS receiver and inertial measurement unit (IMU) located at the platform. The GPS receiver provides GPS navigation data using a plurality of GPS satellites while the inertial measurement unit provides inertial navigation data. Acceleration computed from the GPS navigation data is combined with the inertial acceleration generated from the IMU using a Kalman filter to generate a substantially IMU-bias free acceleration of the platform. The resultant acceleration measurement and the GPS navigation data are used to calculate the velocity of the platform in conjunction with a second Kalman filter for removing GPS systematic errors that are normally removed by use of a ground reference station.
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Citations
43 Claims
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1. An apparatus for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising:
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a GPS receiver located at the platform for receiving a plurality of GPS signals from a corresponding plurality of GPS satellites and outputting GPS navigation data; an inertial measurement unit located at the platform for outputting inertial navigation data indicative of the inertial movement of the platform; a processor for generating an acceleration signal indicative of the acceleration of the platform by combining a first acceleration measurement of the platform calculated from the GPS navigation data with a second acceleration measurement of the platform calculated from the inertial navigation data; and said processor further generating the velocity signal from the acceleration signal and the GPS navigation data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising:
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a GPS receiver located at the platform for receiving a plurality of GPS signals from a corresponding plurality of GPS satellites and outputting GPS navigation data; a processor for processing the GPS navigation data and generating a first acceleration measurement of the platform; an inertial measurement unit located at the platform for outputting inertial navigation data indicative of the inertial movement of the platform; said processor generating a second acceleration measurement of the platform based on the inertial navigation data; an acceleration bias remover for receiving and combining the first acceleration measurement and the second acceleration measurement and substantially removing an acceleration bias generated by the inertial measurement unit to generate a third acceleration measurement of the platform; and said processor further generating a velocity signal from the GPS navigation data and the third acceleration measurement. - View Dependent Claims (12, 13, 14, 15)
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16. A method for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising the steps of:
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receiving a plurality of GPS navigation signals at the platform from a plurality of GPS satellites; generating GPS navigation data from the plurality of GPS navigation signals; measuring inertial movement of the platform using an inertial measurement unit; generating inertial navigation data from the measured inertial movement; calculating a platform acceleration measurement indicative of the acceleration of the platform, said calculating including the steps of; computing a GPS-based platform acceleration measurement using the GPS navigation data; computing an IMU-based platform acceleration measurement using the inertial navigation data; and generating the platform acceleration measurement from the GPS-based platform acceleration measurement and the IMU-based platform acceleration measurement; and processing the GPS navigation data and the platform acceleration measurement to generate the velocity signal. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising the steps of:
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receiving a plurality of GPS navigation signals at the platform from a plurality of GPS satellites; generating GPS navigation data from the plurality of navigation signals; generating a GPS-based acceleration measurement of the platform from the GPS navigation data; measuring inertial movement of the platform using an inertial measurement unit; generating inertial navigation data from the measured inertial movement; generating an IMU-based acceleration measurement of the platform from the inertial navigation data; computing a platform acceleration measurement from the GPS-based acceleration measurement and the IMU-based acceleration measurement using a first Kalman filter; and processing the GPS navigation data and the platform acceleration measurement to generate the velocity signal. - View Dependent Claims (31, 32)
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33. A method for generating a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising the steps of:
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generating ephemeris data, pseudorange data, and carrier phase data from a received GPS signal; computing a GPS satellite velocity measurement and a GPS satellite position measurement in response to the ephemeris data; computing a GPS-based acceleration measurement of the platform from the pseudorange data, the GPS satellite velocity measurement, the GPS satellite position measurement, and the carrier phase data using a least squares acceleration calculation; computing an IMU-based acceleration measurement of the platform from an acceleration measurement received from a platform positioned inertial measurement unit; combining the GPS-based acceleration measurement and the IMU-based acceleration measurement to determine an acceleration signal indicative of the acceleration of the platform; and computing the velocity signal using the pseudorange data, the carrier phase data, the GPS satellite velocity measurement, the GPS satellite position measurement, and the acceleration signal. - View Dependent Claims (34, 35)
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36. An apparatus for determining a velocity signal indicative of the velocity of a platform using a satellite-based navigation system comprising:
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a GPS receiver located at the platform for receiving a plurality of GPS signals from a corresponding plurality of GPS satellites and outputting GPS navigation data; an inertial measurement unit located at the platform for outputting inertial navigation data related to the inertial movement of the platform; a processor for generating an acceleration signal indicative of the acceleration of the platform in accordance with a least square acceleration calculation utilizing the GPS navigation data and the inertial navigation data; and said processor further generating the velocity signal in accordance with a computation utilizing the acceleration signal and the GPS navigation data. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
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Specification