Systems and methods for producing two independent dissimilar attitude solutions, two independent dissimilar inertial solutions or both from one improved navigation device

An attitude heading and reference unit comprising:

• a primary inertial sensor assembly and a secondary processing device both included within a single modular unit;
• a primary inertial sensor assembly configured to produce primary inertial data;
• the primary processing device communicatively coupled to the primary inertial sensor assembly, wherein the primary processing device is configured to receive the primary inertial data and calculate a primary set of attitude solutions from the primary inertial data using a primary set of algorithms;
• a secondary inertial sensor assembly configured to produce secondary inertial data;
• the secondary processing device communicatively coupled to the secondary inertial sensor assembly, wherein the secondary processing device is configured to receive the secondary inertial data and calculate a secondary set of attitude solutions using a second set of algorithms, wherein the primary set of algorithms is different than the second set of algorithms and the secondary processing device calculates a subset of attitude and inertial solutions that the primary processing device calculates;
• and
• wherein, in response to a determination that the difference between a first set of attitude solutions and the primary set of attitude solutions is greater than a threshold, a display device is configured to:
• determine when a first attitude solution from the primary set of attitude solutions is different than a second attitude solution by a first threshold, wherein the second attitude solution is produced by an inertial reference unit other than the attitude heading and reference unit;
• obtain an attitude solution from the secondary processing device to use as a discriminator attitude solution, wherein the first attitude solution, the second attitude solution, and the discriminator attitude solution are each the same one of pitch, roll or heading measurements;
• wherein the display device is further configured such that:
• if the difference between the first attitude solution and the second attitude solution is greater than the first threshold, then the display device will determine whether the primary set of attitude solutions is correct by determining whether the difference between the first attitude solution and discriminator attitude solution is less than a second threshold or whether the difference between the second attitude solution and the discriminator attitude solution is less than the second threshold.

A method for determining which of two dissimilar attitude solutions is correct comprising:

• calculating a first set of attitude solutions using an inertial navigation device;
• calculating a primary set of attitude solutions using an attitude heading and reference unit, wherein calculating the primary set of attitude solutions is done using a primary set of algorithms;
• calculating a secondary set of attitude solutions using the attitude heading and reference unit, wherein calculating the secondary set of attitude solutions is done using a second set of algorithms, wherein the primary set of attitude solutions is calculated by a primary processing device and the a secondary set of attitude solutions is calculated by a secondary processing device, wherein the primary set of algorithms is different than the second set of algorithms, wherein the primary inertial sensor assembly and the secondary processing device are both included within a single modular unit, wherein the secondary processing device calculates a subset of attitude and inertial solutions that the primary processing device calculates, and wherein the inertial navigation device is a separate device from the attitude heading and reference unit;
• and
• determining whether the first set of attitude solutions or the primary attitude solution is correct by determining whether the difference between a first attitude solution from the first set of attitude solutions and a discriminator attitude solution from the secondary set of attitude solutions is less than a threshold or whether the difference between the primary set of attitude solutions and the discriminator attitude solutions is less than a threshold, in response to a determination that the difference between the first set of attitude solutions and the primary attitude solutions is greater than a threshold;
• wherein the first attitude solution, the second attitude solution, and the discriminator attitude solution are each the same one of pitch, roll or heading measurements.