You Are Here:
You are here: SCPI Guide > Command Reference > Source Subsystem > SOURce:ONECHN:LOSDynamics:SETtings

SOURce:ONECHN:LOSDynamics:SETtings

Function

Set the line of sight dynamics parameters for the Signal Generator.

If the profile is running new parameters are memorized, but will be applied only on profile restart.

Command Syntax

SOURce:ONECHN:LOSDynamics:SETtings <J>,<A>,<DA>,<DV>

Parameters

<J> – absolute jerk value in m/s³

<A> – maximum absolute acceleration value in m/s²

<DA> – duration of movement with constant acceleration, positive value, in seconds;

<DV> – duration of movement with constant velocity DV, positive value, in seconds

Introduction to line of sight dynamics profile

This feature supports the simulation of line of sight (LOS) dynamics (velocity profile). This command is effective as of firmware version 7.0.1.

The profile is defined by the following four parameters:

  1. Jerk magnitude J [m/s³]
  2. Maximum acceleration magnitude A [m/s²]
  3. Duration of movement with constant acceleration DA [s]
  4. Duration of movement with constant velocity DV [s]

When the profile is activated the simulator controls the Doppler frequency shift and range variation in accordance with specified parameters as if the receiver was moving along a straight line between it and a satellite(s). Positive velocity corresponds to range increase and negative to Doppler shift.

The profile is defined by a series of jerk pulses (duration of the jerk pulse DJ is given by above parameters J and A: DJ=A/J).

The first jerk pulse is positive with J magnitude and lasts for DJ seconds causing an acceleration increase. After DJ seconds jerk resets to zero resulting in constant acceleration that is maintained for DA seconds. Then negative jerk pulse with J magnitude follows resulting in acceleration decrease during the next DJ seconds. After that the acceleration returns to zero so that a constant velocity is maintained during the next DV seconds. The whole process is depicted in the illustration below. The process is repeated until the profile is stopped.

The initial conditions when the profile is started are as follows:

  • Start jerk J0 = 0 m/s³
  • Start acceleration A0 = 0 m/s²
  • Start velocity = current velocity
  • Start range = current range

When the profile is stopped, the simulator resets jerk and acceleration to zero, but continues to simulate the velocity that was present at the moment when the profile was stopped.

Example

SEND:

SOURce:ONECHN:LOSD:SET 0.005, 0.1, 20, 20

Jerk [m/s³], acceleration [m/s²], velocity [m/s], and range [m] over time [s]