Multiple sensor system and method

• US 5,012,424 A
• Filed: 02/22/1989
• Issued: 04/30/1991
• Est. Priority Date: 02/22/1989
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Dodson, David W.
• Primary Examiner(s): Dixon, Joseph L.
• Application Number:
  US07/313,927
• Time in Patent Office: 797 Days
• Field of Search: 364/559, 364/454, 364/453, 364/457, 364/447, 364/449, 364/550, 364/551.01, 364/434, 364/571.01, 340/988, 342/450, 342/454-457
• US Class Current: 701/207
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

A multiple sensor system and method for computing position and velocity from data from three or more independent and similar inertial sensor units, which are connected to a computer unit, includes: resolving the data from each sensor unit into a common coordinate system for obtaining a unit position vector and a horizontal velocity vector for each of the three sensor units; comparing in a comparison test each unit position vector with a corresponding unit position vector of a selective prior reading thereof for each of the sensor units; comparing in the comparison test each velocity vector with a corresponding velocity vector of a selective prior reading for each of the sensor units; determining by using a selective comparison process which sensor units pass the comparison tests of the comparisons of each of the sensor units, and computing position and velocity using a first selective computing process if less than three sensor units pass their comparison tests, or computing position and velocity using a second selective computing process, if three or more sensor units pass their comparison tests.

Claims

1. A multiple sensor method of computing position and velocity from data from 3 or more sensor units comprising the steps of:

resolving the data from each sensor unit into a common coordinate system for obtaining a unit position vector and a horizontal velocity vector for each of the sensor units;

comparing in a comparison test each unit position vector with a corresponding unit position vector of a selective prior reading thereof for each of the sensor units;

comparing in the comparison test each velocity vector with a corresponding velocity vector of a selective prior reading for each of the sensor units;

determining by using a selective comparison process which sensor units pass the comparison tests of the comparisons of each of the sensor units and which sensor unit is closest to passing if not passing; and

computing position and velocity using a first selective computing process if less than three sensor units pass their comparison tests and using data from one sensor unit either passing its comparison tests or being closest to passing if not passing, or computing position and velocity using a second selective computing process and using data from all sensor units which pass their comparison tests.

2. The method of claim 1, including:

storing an inertial position bias as an error vector in said common coordinate system.

3. The method of claim 1, including:

transforming the unit position vector and the horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.

4. The method of claim 2, including:

transforming the unit position vector and the horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.

5. A multiple sensor method of computing position and velocity from data from a first sensor unit and a second sensor unit and a third sensor unit, comprising the steps of:

resolving the data from the first sensor unit and the data from the second sensor unit and the data from the third sensor unit into a common XYZ coordinate system for obtaining a unit position vector and a horizontal velocity vector for each of the three sensor units;

comparing in a comparison test each unit position vector with a corresponding unit position vector of a selective prior reading thereof for each of the three sensor units;

comparing in the comparison test each velocity vector with a corresponding velocity vector of a selective prior reading for each of the three sensor units;

determining by using a selective comparison process which sensor units pass the comparison tests of the comparisons of each of the three sensor units and which sensor unit is closest to passing if not passing;

computing position and velocity using a first selective computing process if all three sensor units do not pass their comparison tests and using data from one sensor unit either passing its comparison tests or being closest to passing if not passing, or computing position and velocity using a second selective computing process and using data from all three sensor units if all three sensor units pass their comparison tests;

storing an inertial position bias as an error vector in the XYZ coordinate system; and

transforming the unit position vector and the horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.

6. A multiple sensor system comprising:

three or more inertial sensor units;

each said sensor unit having a multi-line output terminal;

a computer having N (N being the number of sensor units) multi-line input terminals with a multi-line connector connecting to each sensor output terminal, said computer having a multi-line output terminal;

said computer having means receiving navigation data from each of said sensor units and resolving said data into a common coordinate system for obtaining a unit position vector and a horizontal velocity vector for each of said sensor units;

means for comparing each unit position vector and velocity vector with a corresponding unit position vector and velocity vector, respectively, of a selective prior reading for each of said sensor units;

means responsive to said comparing means for determining which sensor units pass comparison tests of the data comparisons of each of said sensor units; and

means for computing position and velocity (1) using a first selective computing process if less than three sensor units pass their comparison tests whereby data from a sensor unit providing the best data is utilized or (2) using a second selective computing process whereby data from all sensor units passing their comparison tests are utilized.

7. The system of claim 6, including:

means for storing an inertial position bias as an error vector in said common coordinate system.

8. The system of claim 7, including:

means for transforming the unit position vector and horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.

9. The system of claim 6, including:

means for transforming the unit position vector and horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.

10. A multiple sensor system comprising:

a first sensor unit having three gyroscopes and three accelerometers;

a second sensor unit having three gyroscopes and three accelerometers;

a third sensor unit having three gyroscopes and three accelerometers;

said first and second and third sensor units having respectively a first multi-line output terminal and a second multi-line output terminal and a third multi-line output terminal;

a computer having a first multi-line input terminal with a first multi-line connector connecting to the first sensor output terminal and having a second multi-line input terminal with a second multi-line connector connecting to the second sensor output terminal and having a third multi-line input terminal with a third multi-line connector connecting to the third sensor output terminal, said computer having a multi-line output terminal;

said computer having means receiving navigation data from each of said sensor units and resolving said data into a common coordinate system for obtaining a unit position vector and a horizontal velocity vector for each of said sensor units;

means for comparing each unit position vector and velocity vector with a corresponding unit position vector and velocity vector, respectively, of a selective prior reading for each of said sensor units;

means responsive to said comparing means for determining which sensor units pass comparison tests of the data comparisons of each of said sensor units;

means for computing position and velocity (1) using a first selective computing process if less than three sensor units pass their comparison tests whereby data from a sensor unit providing the best data is utilized or (2) using a second selective computing process whereby data from all sensor units passing their comparison tests are utilized;

means for storing an inertial position bias as an error vector in said common coordinate system; and

means for transforming the unit position vector and horizontal velocity vector as computed to a geodetic latitude/longitude system for use by a user.