finals removal

satgeod

• TRILATERATION

• THE POSITIONS OF THE SATELLITES (KNOWN POINTS) AND THE DISTANCES FROM THE RECEIVER TO THOSE SATELLITES

In GNSS positioning, determining an unknown receiver position relies on measuring distances rather than angles. What is the specific surveying principle used, and what minimum geometric information must be known before the unknown position can be computed?

THE EARTH (EARTH ACTS AS THE FOURTH SPHERE)

During three-dimensional satellite positioning, the intersection of three range spheres mathematically produces two possible receiver locations. What natural body provides the additional geometric constraint that eliminates the incorrect solution?

EPHEMERIS (BROADCAST EPHEMERIS)

The positional information transmitted by each GPS satellite is regularly updated by the control segment. What is the technical name of the orbital document containing these predicted orbital parameters?

ALMANAC

Besides broadcasting its own orbital parameters, every GPS satellite also transmits a less accurate summary of the orbital information for the entire satellite constellation. What is this dataset called?

PSEUDORANDOM NOISE (PRN) CODE

Before computing the distance to a satellite, the GPS receiver must first determine which satellite transmitted the received signal. What unique digital identifier embedded within every navigation signal allows this identification?

CORRELATION = 1 (PERFECT CORRELATION)

A GPS receiver determines that it has identified the correct satellite when the correlation between the internally generated code and the received code reaches what specific value?

PSEUDORANGE

The measured distance between a GPS satellite and a receiver is not initially considered the true geometric distance because of unsynchronized clocks. What is the technical name given to this approximate distance?

SPEED OF LIGHT (299,792,458 m/s)

The basic ranging equation used in GPS multiplies the elapsed signal travel time by a universal physical constant. What is this constant?

RECEIVER CLOCK BIAS (CLOCK OFFSET)

In the GPS pseudorange observation equation, four unknown parameters must be solved simultaneously. Besides the receiver's three spatial coordinates, what is the fourth unknown?

RECEIVER CLOCK BIAS

Although three satellites are theoretically sufficient to determine a three-dimensional position, GPS positioning normally requires one additional satellite. What specific receiver parameter does the fourth satellite primarily determine?

• L1 (1575.42 MHz)

• L2 (1227.60 MHz)

High-precision GPS surveying refines positioning by using the radio carrier instead of only the navigation code. What are the two standard GPS carrier frequencies?

L1 CARRIER

Which GPS carrier possesses the shorter wavelength because of its higher transmission frequency?

INTEGER AMBIGUITY

When carrier-phase positioning is first initialized, the total number of complete wavelengths between the receiver and the satellite is unknown. What is the technical term for this unknown integer?

POST-PROCESSING

What mathematical process is performed after field observations to resolve integer ambiguities and remove orbital, clock, and atmospheric errors?

AMBIGUITY FIXING

During post-processing, GPS software reports the percentage of ambiguities that have been successfully resolved. What is the technical term for this process?

INTEGER AMBIGUITY

Combining the L1 and L2 carrier frequencies to produce a signal with a much longer wavelength is intended primarily to simplify the resolution of what parameter?

• SPACE SEGMENT

• CONTROL SEGMENT

• USER SEGMENT

GPS is divided into three major operational components. Identify these three segments.

CONTROL SEGMENT

Which GPS segment continuously monitors satellite health, computes orbital corrections, and uploads updated navigation messages?

MASTER CONTROL STATION (MCS)

What facility serves as the central processing unit of the GPS Control Segment, responsible for computing updated satellite ephemerides and clock corrections?

KALMAN FILTERING

Which statistical estimation technique is employed by monitoring stations to smooth pseudorange observations before transmitting them to the Master Control Station?

P-CODE (PRECISE CODE)

GPS positioning signals employ two different ranging codes. Which code provides the higher positioning precision because of its higher chipping rate?

C/A CODE (COARSE/ACQUISITION CODE)

Which GPS code is openly available to civilian users and repeats its chip sequence every millisecond?

HAND-OVER WORD (HOW)

The satellite navigation message contains a field that marks the beginning of each message frame and assists synchronization. What is this field called?

TIME OF WEEK (TOW)

What quantity is obtained by multiplying the numerical value contained in the Hand-Over Word by four?

IONOSPHERE

GPS observable errors include atmospheric delays occurring in the electrically charged upper atmosphere. What is the name of this atmospheric layer?

MULTIPATH

Reflected satellite signals arriving at the antenna through multiple paths produce a significant positioning error. What is this error called?

DILUTION OF PRECISION (DOP)

GPS position quality depends strongly on satellite geometry. What dimensionless indicator expresses the geometric strength of the visible satellite configuration?

DOUBLE DIFFERENCING

Which differencing technique simultaneously eliminates both receiver clock errors and satellite clock errors by combining observations from two receivers and two satellites?

• BASE RECEIVER

• ROVER RECEIVER

In differential GPS surveying, what are the names of the receiver located at the known control point and the receiver positioned at the unknown location?

AMBIGUITY RESOLUTION ON THE FLY (AROF) / ON-THE-FLY (OTF) AMBIGUITY RESOLUTION

During RTK surveying, ambiguity resolution while the receiver remains continuously in motion is known by what specific technique?