Novatel OM-20000077 user manual Built-In Status Tests, Dead-Reckoning Mode

Operation Chapter 4

mode only. The receiver reports its current navigation sub-mode on its host port.

Your receiver must be a BASE model to act as a base station. A list of models is in Appendix A of the L1 GPS Firmware Reference Manual and in our Price List available from the Sales side menu of our website at www.novatel.com.

a. Differential (Roving Unit Only)

The receiver operates in Differential mode when data from at least 4 satellites with adequate geometry and differential corrections and/or measurements exist to compute position, velocity and time outputs. This is the preferred navigation mode. Differential data is supplied to the receiver through the differential input port. Differential data can be received only on the COM2 serial data port.

b. Stand-Alone Nav (Roving Unit Only)

The receiver operates in Stand-Alone Nav mode when it has data from at least 4 satellites with adequate geometry, but no differential corrections or measurements, exist to compute position, velocity and time outputs. This is the preferred navigation mode when insufficient differential data is available to generate a differential GPS fix.

c. Base Station Nav (Base Station Unit Only)

The receiver operates in Base Station Nav mode once the time has been initialized and at least 4 satellites with adequate geometry can be used for navigation purposes. Once in this mode, only a change of configuration (rover mode requested) or a reset will cause the unit to leave this navigation mode. In this mode, the unit will have the ability to transmit the DGPS messages which are requested and allowed once its position is initialized. See also Section 4.4, Configurable Parameters starting on Page 31 for position initialization details.

5.Dead-Reckoning Mode

The receiver enters Dead-Reckoning mode when it cannot remain in Navigation mode. The speed and direction is assumed to be constant to allow the receiver to provide an estimated position.

6.Fault Mode

The receiver enters Fault mode during the period of time in which the receiver outputs are affected by one or more critical system faults. This mode supersedes all others and remains active until the next power-down/power-up cycle. Fault mode is entered from any mode except Initialization.

4.6Built-In Status Tests

The receiver performs self-tests and generates status information to provide an indication of the operational readiness and to facilitate maintenance actions.

The built in test monitors system performance and status to ensure the receiver is operating within its specifications. If an exceptional condition is detected, you are informed through one or more indicators. The receiver status system is used to configure and monitor these indicators:

•Message ID# 49, Receiver Status Data

•Message ID# 51, Initiated BIT Result

•Status LED on the FlexPak-SSII

Please refer to the L1 GPS Firmware Reference Manual for details on the Message IDs above. See also Section 4.5.2, Operational States starting on Page 31 and status LED information may be found in this manual on Page 50.

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