Method and device for determining navigation data

• US 10,151,587 B2
• Filed: 03/06/2015
• Issued: 12/11/2018
• Est. Priority Date: 03/10/2014
• Status: Active Grant

• Current Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Inventors: Huellenkremer, Manfred, Krings, Manfred
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): Kong, Sze-Hon
• Application Number:
  US15/124,548
• Publication Number:
  US 20170016729A1
• Time in Patent Office: 1,376 Days
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/203 Specially adapted for sailing ships
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial

Abstract

In a method for determining navigation data, positional angle measurement values are determined using a first navigation device (310). A second navigation device (320) is then initialized using the positional angle measurement values determined by the first navigation device (310). Both navigation devices are supplied with rotational rate and acceleration measurement values from a common sensor unit in order to determine the positional angle measurement values. In the process, the first navigation device (310) produces erroneous measurements of the positional angle measurement values with a probability which is lower than as specified positional angle error rate, and the second navigation device (320) produces erroneous measurements of the positional angle measurement values with a probability which is higher than the specified positional angle error rate. An erroneous measurement of the positional angle measurement values is present if one of the determined positional angle measurement values deviates from a corresponding positional angle reference value by more than a specified positional angle tolerance value.

Claims

1. A method for determining navigation data, comprising:

determining positional angle measurement values with a first navigation device; and

initializing a second navigation device with the positional angle measurement values determined by the first navigation device, wherein

rotation rate and acceleration measurement values for determining the positional angle measurement values are supplied to the first navigation device and the second navigation device from a sensor unit;

wherein

the first navigation device carries out erroneous measurements of the positional angle measurement values with a probability that is smaller than a predetermined positional angle error rate;

the second navigation device carries out erroneous measurements of the positional angle measurement values with a probability that is larger than the predetermined positional angle error rate;

an erroneous measurement of the positional angle measurement values occurs when one of the determined positional angle measurement values deviates by more than a predetermined positional angle tolerance value from a respective positional angle reference value; and

no erroneous measurement of the positional angle measurement values occurs when none of the determined positional angle measurement values deviates by more than the predetermined positional angle tolerance value from the respective positional angle reference value.

2. The method according to claim 1, further comprising:

determining a track angle measurement value simultaneously to determining the positional angle measurement value,

initializing the second navigation device with the positional angle measurement values and the track angle measurement values determined by the first navigation device, wherein

erroneous measurements of the track angle measurement value occur with a probability that is smaller than a predetermined track angle error rate;

an erroneous measurement of the track angle measurement value occurs when the determined track angle measurement value deviates by more than a predetermined track angle tolerance value from a respective track angle reference value; and

no erroneous measurement of the track angle measurement value occurs when the determined track angle measurement value does not deviate by more than the predetermined track angle tolerance value from the respective track angle reference value.

3. The method according to claim 2, wherein the track angle measurement value is determined by the first navigation device, by a magnetic sensor or by a manual input.

4. The method according to claim 1, further comprising:

determining positional and track angle measurement values with the second navigation device temporarily after initializing the second navigation device with the positional angle measurement values determined by the first navigation device;

determining of positional angle measurement values with the first navigation device during determining track and positional angle measurement values with the second navigation device;

comparing the positional angle measurement values determined by the first navigation device and the second navigation device, wherein

if the determined positional angle measurement values deviate from each other by less than the predetermined positional angle tolerance value,

then, re-initialization of the first navigation device with the positional and track angle measurement values determined by the second navigation device; and

then, navigating based on the positional and track angle measurement values determined by the second navigation device.

5. The method according to claim 1, wherein

the first navigation device comprises a first navigation platform;

and

the second navigation device comprises a second navigation platform, a satellite navigation system, and a Kalman filter, which couples the data of the second navigation platform and the satellite navigation system.

6. The method according to claim 5, wherein the first navigation platform and the second navigation platform are the same.

7. The method according to claim 1, wherein the first and the second navigation devices as well as the sensor unit are not accelerated during determining of the angles for the first time, or the first and the second navigation devices as well as the sensor unit are accelerated during determining of the angles for the first time such that a temporal average of the accelerations cancel.

8. A device for determining navigation data, comprising:

a first navigation device for determining positional angle measurement values;

a second navigation device for determining positional angle measurement values, the second navigation device being initialized with positional angle measurement values determined by the first navigation device; and

a sensor unit that supplies rotation rate and acceleration measurement values for determining the positional angle measurement values to the first navigation device and the second navigation device, wherein

the first navigation device carries out erroneous measurements of the positional angle measurement values with a probability that is smaller than a predetermined positional angle error rate;

the second navigation device carries out erroneous measurements of the positional angle measurement values with a probability that is larger than a predetermined positional angle error rate; and

wherein

an erroneous measurement of the positional angle measurement values occurs when one of the determined positional angle measurement values deviates by more than a predetermined positional angle tolerance value from a respective positional angle reference value, and

no erroneous measurement of the positional angle measurement values occurs when none of the determined positional angle measurement values deviates by more than the predetermined positional angle tolerance value from the respective positional angle reference value.

9. The device according to claim 8, wherein

the first navigation device is configured to determine a track angle measurement value temporarily after determining the positional angle measurement value;

the second navigation device is configured to be initialized with the angular measurement values determined by the first navigation device;

erroneous measurements of the track angle measurement value occur with a probability that is smaller than a predetermined track angle error rate;

erroneous measurements of the track angle measurement value occurs when the determined track angle measurement value deviates by more than a predetermined track angle tolerance value from a respective track angle reference value; and

no erroneous measurements of the track angle measurement value occur when the determined track angle measurement value does not deviate by more than the predetermined track angle tolerance value from the respective track angle reference value.

10. The device according to claim 8, wherein

the second navigation device is configured to determine positional angle and track angle measurement values temporarily after initializing the second navigation device with the positional angle measurement values determined by the first navigation device;

the first navigation device is configured to determine the positional angles during determining the positional angles and the track angle with the second navigation device;

the first navigation device and the second navigation device are configured to compare the determined values of the positional angles; and

wherein

if the determined positional angle measurement values deviate by less than the predetermined positional angle tolerance value from each other,

then, the first navigation device is configured to be re-initialized with the positional and track angle measurement values determined by the second navigation device; and

then, the second navigation device is configured to navigate based on the positional and track angle measurement values determined by the second navigation device.

11. The device according to claim 8, wherein

the first navigation device comprises a first navigation platform;

and

the second navigation device comprises a hybrid navigation platform with a second navigation platform, a satellite navigation system and a Kalman filter, which couples the data of the second navigation platform and the satellite navigation system.