Glossary

range

A term used to refer to the distance radio signals can travel

 

before they must be received or repeated due to loss of

 

signal strength, the curvature of the earth and the noise

 

introduced because of moisture in the air surrounding the

 

earth's surface.

range rate

The rate of change of range between the satellite and

 

receiver. The range to a satellite changes due to satellite and

 

observer motions. Range rate is determined by measuring

 

the Doppler shift of the satellite beacon carrier.

read-only memory

Memory whose contents can be read, but not changed.

 

Information is placed into ROM only once. The contents of

 

ROM are not erased when the system unit's power is turned

 

off.

relative

The process of determining the vector distance between two

positioning

points and the coordinates of one spot relative to another.

 

This technique yields GPS positions with greater precision

 

than a single point positioning mode can.

rise/set time

The period during which a satellite is visible (i.e., has an

 

elevation angle that is above the elevation mask). A satellite

 

is said to "rise" when its elevation angle exceeds the mask

 

and "set" when the elevation drops below the mask.

ROM

Read-Only Memory.

RTCM

Radio Technical Commission for Maritime Services.

 

Commission that recommends standards for differential

 

GPS services. RTCM Recommended Standards For

 

Differential GPS Service, prepared by RTCM Special

 

Committee No. 104 (RTCM SC-104), defines a

 

communication protocol for sending GPS differential

 

corrections from a differential reference station to remote

 

GPS receivers.

Glossary-10

Acutime 2000 Synchronization Kit User Guide

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Trimble Outdoors Part Number 45005-00-ENG, AcutimeTM2000 Synchronization Kit manual Rom