Moog Crossbow GNAV540 - Manual (Page 19)

NAV540 User Manual
7430‐0808‐01 Rev. B
Page 19 G
temperature and non‐linearity effects during Crossbow’s manufacturing and test process using automated
thermal chambers and rate tables.
• Coupled to the 6‐DOF MEMS inertial sensor cluster is a high performance Digital Signal Processor (DSP) that
utilizes the inertial sensor measurements to accurately compute navigation information including attitude,
heading, and linear velocity thru dynamic maneuvers (actual measurements are a function of the GNAV540
as shown in Table 2).
The DSP processor makes use of internal and external magnetic sensor and/or GPS data to aid the
performance of the inertial algorithms and help correct long term drift and estimate errors from the inertial
sensors and computations. The navigation algorithm utilizes a multi‐state configurable Extended Kalman
Filter (EKF) to correct for drift errors and estimate sensor bias values. This algorithm runs on a 150MHz
32‐bit DSP that has approximately four times the computational power of Crossbow’s earlier generation
Inertial Systems.
• A significant feature of the GNAV540 is the extensive field configurability.
This field configurability allows the GNAV540 Inertial Systems to satisfy a wide range of applications and
performance requirements with a single mass produced hardware platform. The basic configurability
includes parameters such as baud rate, packet type, and update rate, and the advanced configurability
includes the defining of custom axes and how the sensor feedback is utilized in the Kalman filter during the
navigation process.
The GNAV540 unit is packaged in a fully sealed, lightweight housing that provides EMI, vibration and moisture
resistance to levels consistent with most land, marine, and airborne environments. The GNAV540 utilizes an RS‐422
serial link or Ethernet interface for data communication, and each data transmission includes a BIT (Built‐In‐Test)
message providing system health status. The GNAV540 is supported by Crossbow’s NAV‐VIEW 2.2, a powerful PC‐
ased operating tool that provides complete field configuration, diagnostics, charting sensor performance, and data
ogging with playback.
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