CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Indian Provisional Patent Application No. 202111015604, filed Apr. 1, 2021, the entire content of which is incorporated by reference herein.

TECHNICAL FIELD

The technical field generally relates to searchlight control systems on mobile platforms, and more particularly, relates to searchlight control systems and methods for moving a beam of light emitted by a searchlight on a mobile platform at a constant ground speed.

BACKGROUND

Searchlight control systems generally include a searchlight mounted on a mobile platform (referred to herein as a mobile platform searchlight). The searchlight is an illumination apparatus that emits a beam of light. The beam of light has an illumination spot that may be used to illuminate a point of interest on the ground while the mobile platform is in the air.

In operation of available searchlight control systems, a light emitting source (such as an LED array) in the searchlight emits the beam of light. Movement of the beam of light and associated illumination spot on the ground is generally controlled with elevation actuators and azimuth actuators that are operationally coupled to the light emitting source (such as an LED array) in the searchlight. An azimuth/elevation command generally causes an actuator angle change in the respective actuator, which results in a movement of the illumination spot on the ground.

In available systems, the rate of change of the actuators' angles often remains constant, meaning that, to achieve movement of the beam of light, the azimuth actuators are rotated at a nearly constant average angular velocity. However, moving the beam of light at a constant angular speed has various drawbacks.

Accordingly, improved searchlight control systems and methods are desirable. The following disclosure provides these technological enhancements, in addition to addressing related issues.

BRIEF SUMMARY

This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Provided is a system for moving a beam emitted by a searchlight on a mobile platform at a constant groundspeed. The system comprising: a searchlight apparatus comprising the searchlight, an elevation actuator, and an azimuth actuator, the search light mounted on the mobile platform with a known mounting orientation and operationally coupled to the elevation actuator and the azimuth actuator, the elevation actuator configured to respond to elevation actuator commands to move to an elevation actuator angle, the azimuth actuator configured to respond to azimuth actuator commands to move to an azimuth actuator angle; a source of a known mounting orientation for the searchlight, the elevation actuator angle and the azimuth actuator angle; a user input device; and a controller architecture integrated with the searchlight apparatus, the source of a known mounting orientation, and the user input device, and programmed by programming instructions to: receive SL-status data for the mobile platform, the SL-status data comprising an attitude and altitude; compute an elevation angle, theta, of the beam as a function of the attitude, the elevation actuator angle and the known mounting orientation for the searchlight; compute an azimuth angle, Psi, of the beam as a function of the attitude, the azimuth actuator angle and the known mounting orientation for the searchlight; receive a searchlight control command from the user input device; determine, responsive to the searchlight control command, a respective rate of change of theta, dtheta/dt and a rate of change of Psi, dPsi/dt, required to maintain the constant groundspeed of the illumination spot, as a function of the SL-status data; update theta responsive to the determined dtheta/dt; update Psi responsive to the determined dPsi/dt; and generate azimuth actuator commands and elevation actuator commands, as a function of dPsi/dt and dtheta/dt.

Another system for moving an illumination spot of a beam emitted by a searchlight on a mobile platform at a constant groundspeed is provided. The system comprising: a controller module, the controller module configured to: reference a known mounting orientation on the mobile platform for the searchlight; compute attitude of the mobile platform; compute an elevation angle (theta) of the beam as a function of the attitude of the mobile platform, an elevation actuator angle and the known mounting orientation for the searchlight; compute an azimuth angle, Psi, of the beam as a function of the attitude, the azimuth actuator angle and the known mounting orientation for the searchlight; and an input interface module operating onboard the mobile platform, the input interface module configured to: receive a searchlight control command from a pilot; generate, as a function of the searchlight control command, a slew azimuth signal and a slew elevation signal; and communicate the slew azimuth signal and slew elevation signal to the searchlight control module; the controller module further configured to: determine, responsive to the slew elevation signal and slew azimuth signal, a respective rate of change of theta, dtheta/dt and a rate of change of Psi, dPsi/dt, required to maintain the constant groundspeed of the illumination spot, as a function of the SL-status data; update theta responsive to the determined dtheta/dt; update Psi responsive to the determined dPsi/dt; and generate azimuth actuator commands and elevation actuator commands, as a function of dtheta/dt and dPsi/dt.

A method for moving an illumination spot of a beam emitted by a searchlight on a mobile platform at a constant groundspeed is provided. The method comprising: at a processor, receiving SL-status data comprising an attitude for the mobile platform; computing an elevation angle, theta, of the beam as a function of the attitude, an elevation actuator angle and a known mounting orientation for the searchlight; receiving a searchlight control command comprising a searchlight elevation control command and an azimuth control command from a user input device; determining, responsive to the searchlight elevation control command, a respective rate of change of theta, dtheta/dt, required to maintain the constant groundspeed of the illumination spot, as a function of the SL-status data; determining, responsive to the searchlight azimuth control command, a respective rate of change of Psi, dPsi/dt, required to maintain the constant groundspeed of the illumination spot, as a function of the SL-status data; generating elevation actuator commands, as a function of dtheta/dt; and generating azimuth actuator commands as a function of dPsi/dt.

Furthermore, other desirable features and characteristics of the system and method will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.

