A method of implementing a fault-tolerant-avionic architecture in a vehicle comprising: using parity logic to monitor the functionality of at least three non-fault-tolerant inertial measurement units (100, 300, 400) during a parity check, each inertial measurement unit comprising at least one triad of sensors (110, 120), wherein using the parity logic comprises: receiving information indicative of measurements of one of acceleration, rate, and both rate and acceleration from the inertial measurement units; forming measurement vectors based on a square of a magnitude of the received information indicative of measurements, wherein the measurement vectors are one of an acceleration vector, a rate vector, and both the rate vector and the acceleration vector; transposing the measurement vectors in a measurement space into parity vectors in a parity space; and dynamically calculating a magnitude squared of the parity vectors; dynamically calculating a threshold for the magnitude squared of the parity vectors from expected inertial measurement unit performance during a parity check, the expected inertial measurement unit performance including at least one of: an expected value from sensed acceleration; and an expected value for the sensed angular velocity; comparing the magnitude squared of the parity vectors to the threshold; determining a failure of an inertial measurement unit when a magnitude of a parity vector is greater than the threshold; and if a failure of an inertial measurement unit is detected, based on the monitoring the at least three non-fault-tolerant inertial measurement units during the parity check, the method further comprises: identifying the failed inertial measurement unit based on a direction of a parity vector in parity space, the direction of the parity vector indicated by respective theta angles (θ 1 -θ 4), wherein a smallest theta angle (θ i) indicates the direction along which the parity vector lies and identifies the worst performing inertial measurement unit. using parity logic to monitor the functionality of at least three non-fault-tolerant inertial measurement units (100, 300, 400) during a parity check, each inertial measurement unit comprising at least one triad of sensors (110, 120), wherein using the parity logic comprises: receiving information indicative of measurements of one of acceleration, rate, and both rate and acceleration from the inertial measurement units; forming measurement vectors based on a square of a magnitude of the received information indicative of measurements, wherein the measurement vectors are one of an acceleration vector, a rate vector, and both the rate vector and the acceleration vector; transposing the measurement vectors in a measurement space into parity vectors in a parity space; and dynamically calculating a magnitude squared of the parity vectors; receiving information indicative of measurements of one of acceleration, rate, and both rate and acceleration from the inertial measurement units; forming measurement vectors based on a square of a magnitude of the received information indicative of measurements, wherein the measurement vectors are one of an acceleration vector, a rate vector, and both the rate vector and the acceleration vector; transposing the measurement vectors in a measurement space into parity vectors in a parity space; and dynamically calculating a magnitude squared of the parity vectors; dynamically calculating a threshold for the magnitude squared of the parity vectors from expected inertial measurement unit performance during a parity check, the expected inertial measurement unit performance including at least one of: an expected value from sensed acceleration; and an expected value for the sensed angular velocity; an expected value from sensed acceleration; and an expected value for the sensed angular velocity; comparing the magnitude squared of the parity vectors to the threshold; determining a failure of an inertial measurement unit when a magnitude of a parity vector is greater than the threshold; and if a failure of an inertial measurement unit is detected, based on the monitoring the at least three non-fault-tolerant inertial measurement units during the parity check, the method further comprises: identifying the failed inertial measurement unit based on a direction of a parity vector in parity space, the direction of the parity vector indicated by respective theta angles (θ 1 -θ 4), wherein a smallest theta angle (θ i) indicates the direction along which the parity vector lies and identifies the worst performing inertial measurement unit.