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Integrated GPS/inertial navigation apparatus providing improved heading estimates

  • US 5,657,025 A
  • Filed: 08/07/1995
  • Issued: 08/12/1997
  • Est. Priority Date: 08/07/1995
  • Status: Expired due to Term
First Claim
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1. Apparatus for use with two antennas on a mobile platform, the two antennas being capable of receiving signals from one or more satellites, each satellite signal comprising one or more component signals, each component signal having a different carrier frequency, the apparatus comprising:

  • a receiver which obtains satellite ephemeris data and measures the carrier phase of each of one or more component signals of one or more satellite signals received from one or more satellites by each of the two antennas during successive time periods of duration Tp, phase measured during a Tp time period being called Tp -phase, only one component signal of one satellite signal received by one antenna being measured during any single Tp time period, the receiver utilizing the Tp -phases of each component signal obtained during a Tk time period by each antenna to estimate the phase of the component signal at the end of the Tk time period, the estimated phase at the end of the Tk time period being called the Tk -phase, Tk being equal to or greater than Tp ;

    an inertial navigation system comprising inertial sensors and a digital processor, the inertial navigation system utilizing measurements of platform acceleration and platform angular rotation rate in determining the positions of the two antennas and the heading of the platform, the inertial navigation system utilizing the satellite ephemeris data and the positions of the two antennas to obtain computed ranges from the two antennas to the satellites, the inertial navigation system utilizing the computed ranges and the Tk -phases in determining the error in the heading of the vehicle.

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