Apparatus and method for pointing a directional device from a moving vehicle toward a spacecraft

• US 6,377,211 B1
• Filed: 12/13/2000
• Issued: 04/23/2002
• Est. Priority Date: 12/13/2000
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Hsiung, Chia Yi
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/735,682
• Time in Patent Office: 496 Days
• Field of Search: 342/359, 343/757, 701/220
• US Class Current: 342/359
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/51 Relative positioning
• CPC Class Codes: H01Q 1/125 Means for positioning
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 3/00 Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system means for positioning H01Q1/125

Abstract

An antenna aiming or pointing apparatus and method is mounted on a vehicle, which may be moving or mobile, for pointing a directional antenna toward a spacecraft in a nongeosynchronous orbit. Since the vehicle moves, its attitude in terms of pitch, roll and azimuth or yaw change from time to time. As a consequence, neither the spacecraft nor the vehicle have a fixed location. The antenna pointing arrangement includes vehicle-mounted sensors for determining roll and pitch, and a compass for determining, with magnetic correction, the azimuth of the vehicle. In addition, the vehicle pointing system includes a GPS receiver, which produces signals indicative of the vehicle location and the current time. The system includes memory which is loaded from time to time with spacecraft orbital information as a function of time. The memory can be loaded from the internet by wireless Internet or by hard wire when the vehicle is stationary. A processor calculates the time-varying antenna pointing direction taking into account the vehicle attitude and azimuth. The antenna controller points a beam of the antenna toward the spacecraft based upon the pointing direction in vehicle-centric coordinates (190).

Claims

1. An antenna pointing method for pointing an antenna on a mobile platform toward a spacecraft for communications therewith, the apparent location of which spacecraft moves relative to a fixed location on the earth'"'"'s surface, said pointing method comprising the steps of:

storing data representative of the location of said spacecraft as a function of time to thereby produce stored data;

determining a location of said mobile platform from GPS signals;

determining the pitch, roll and yaw of said mobile platform relative to the horizontal and an ordinate direction;

determining the current time from said GPS signals;

from said stored data and said current time, determining the location of said spacecraft at said current time;

from said location of said spacecraft and said location, pitch, roll and yaw of said mobile platform, determining an azimuth and elevation pointing direction from said location of said mobile platform to said spacecraft; and

pointing an antenna beam in said azimuth and elevation direction from said mobile platform.

2. A method according to claim 1, wherein said spacecraft includes an antenna defining a polarization, and further comprising the steps of:

storing data representative of the polarization of said antenna on said spacecraft as a function of time, to thereby produce spacecraft polarization information;

from said spacecraft polarization information and said current time, determining the apparent polarization of said antenna on said spacecraft; and

setting the polarization of said antenna beam to about said apparent polarization.