Lidar Simulation Model: Platform/Instrument Inputs


The model inputs that govern laser shot coverage, characterize the instrument system, laser and signal processing are entered via a series of input screens.

PLATFORM SCREEN

Platforms supported in the LSM are satellites and aircrafts. Future platforms that are intended to be included are balloon and ground-based systems.

SATELLITE

Orbit Inclination Angle

The starting inclination angle of the satellite orbit counter-clockwise from starboard.

Pointing Offset

Accuracy of platform attitude knowledge (bias).

Pointing Jitter

Unrecorded high frequency variation in platform attitude.

AIRCRAFT

Aircraft Inventory

The user chooses an existing aircraft flight file from the inventory.

Aircraft Heading

Overall heading adjustment made to the existing aircraft file.

Aircraft Attitude Option

There are three aircraft attitude options: do not include roll, pitch yaw effects, use roll. pitch, yaw effects from the aircraft file , roll, pitch, yaw effects computed by model.

LATITUDE/LONGITUDE

Starting location of the satellite or a location adjustment of the aircraft flight track.

ALTITUDE

Starting Altitude of the Satellite or Aircraft.

LASER SCREEN

Laser Energy

The transmitted energy of the laser pulse.

Laser Wavelength

The wavelength of the laser.

Pulse Duration

The length of the laser pulse expressed in time.

Frequency Stability

The standard deviation of the output frequency.

Peak PRF

Maximum pulse repetition frequency capability over short time intervals given thermal and power constraints.

Design PRF

Design pulse repetition frequency average operations point.

OPTICS SCREEN

Efficiency

Transmission efficiency of the lidar's optimal subsystems, expressed as a number between 0 and 1.

Beam Quality

Factor that expresses the accumulated wave front error for the entire optical path.

TELESCOPE SCREEN

Conical Scanner

The beam is continuous scanned azimuthally at a fixed angle to nadir.

Step-stare

The beam is stepped, either clockwise or counter-clockwise through a conical scan, pausing at prescribed azimuth angles for prescribed dwell times.

Fixed Beam

The beam is pointed at a fixed azimuth angle relative to the platform.

Diameter Primary

The size of the primary telescope mirror.

DETECTOR SCREEN

Quantum Efficiency

Photonic to electronic conversion factor.

SHOT MANAGEMENT SCREENS:

For the CONICAL scanner,

Nadir Scan Angle

The slant path angle referenced from nadir.

Scan Rate

Revolution rate of the scanner.

PRF

Pulse repetition rate.

Cosine Modulation

Modulation switch applies a cosine modification to pulse timing during a conical scan.

For the FIX BEAM and the STEP-STARE BEAM

Number of Telescopes

The user may choose up to twenty telescopes placed in any sequence order.

The following indented inputs must be entered for each telescope:

Azimuth Angle

The azimuth angle for the dwell period referenced counter-clockwise from starboard.

Nadir Scan Angle

The slant path angle referenced from nadir.

Dwell Time

The length of time to stay at a fixed azimuth angle.

Dwell PRF

The PRF for the dwell period.

Gap Time

The length of time not to fire the laser between dwell periods for fixed beam scanners or the length of time to conically scan and fire the laser for step-stare scanners.

Gap PRF

The PRF for the step-stare scanner's conical scan period between dwell periods.

Directional Indicator

For the Step-stare beam only, a directional component (clockwise or counter-clockwise) of the conic scans between dwell periods must be entered for each telescope.

Cycle Period

The length of time before repeated the telescope pattern.

Pointing Jitter

Unrecorded high frequency variation in scanner.

SIGNAL PROCESSING SCREEN

The user can choose either Pulse-Pair Autocorrelation method or a Consensus Algorithm for signal processing.

Pulse-Pair Autocorrelation - Narrow-band SNR based

SNR error threshold

SNRn threshold used in the SNR weighting function.

Velocity Wind Maximum

Maximum atmospheric wind velocity measured Window.

Consensus Algorithm - Wide-band SNR

Velocity bandwidth

Maximum atmospheric wind velocity window.

Line-of -Sight Uncertainty

Line-of-sight uncertainty used for a signal that passed consensus.


This page managed by Sidney A. Wood Last modified: 21 Feb. 1998