Mobile surface terminal communication system

• US 20030190889A1
• Filed: 04/03/2002
• Published: 10/09/2003
• Est. Priority Date: 04/03/2002
• Status: Active Grant

• Current Assignee: Aerospace Corporation
• Original Assignee: Aerospace Corporation
• Inventors: Nguyen, Tien M., Holmes, Jack K.
• Granted Patent: US 6,804,493 B2
• Time in Patent Office: Days
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18573 for operations control, administration or maintenance

Abstract

A command and telemetry communication system includes a downlink subsystem having a spacecraft downlink transmitter communicating a quadrature component carrying a pilot code for coarse acquisition and an inphase component carrying a Walsh-Hadamard code and a PN code for fine acquisition using spread spectrum signaling and amplitude modulation for code division multiplexing to downlink receivers respectively disposed in a plurality of mobile surface landers, and includes an uplink subsystem having a spacecraft uplink receiver and lander uplink transmitters communicating code division multiple access telemetry data using spread spectrum signaling and phase modulation. The communication system enables command and telemetry control of a plurality of mobile surface landers.

Claims

1. A system for communicating respective command data from a central transceiver to respective mobile terminals over a downlink and for communicating respective telemetry data from the respective mobile terminals to the central system over an uplink, the system comprising,

a central transmitter of the central transceiver for transmitting respective downlink signals over the downlink for communicating the respective command data from the central transceiver to the respective mobile terminals, the downlink signals are spectrum spread in quadrature with the respective command data and respective first codes and a second code amplitude modulating a downlink carrier on a first quadrature component with a third code amplitude modulating the downlink carrier on a second quadrature component,

a central receiver of the central transceiver for receiving respective uplink signals over the uplink communicating the respective telemetry data from the respective mobile terminals to the central transceiver, the central receiver comprising a bank of respective uplink receivers for respectively receiving the respective uplink signals carrying the respective telemetry data from the respective mobile terminals,

mobile transmitters respectively for the respective mobile terminals, the mobile transmitters transmitting the respective uplink signals over the uplink for transmitting the respective telemetry data from the respective mobile terminals to the central receiver, the respective uplink signals from respective mobile terminals are spectrum spread using respective fourth codes phase modulating an uplink carrier, and

mobile receivers respectively for the respective mobile terminals, the mobile receivers respectively receiving the respective downlink signals over the downlink for respectively receiving the respective command data from the central transmitter, the respective downlink signals are coarsely acquired using the third code on the second quadrature component, and then finely acquired using the respective first codes and the second code on the first quadrature component.

2. The system of claim 1 wherein,

the central transceiver is on-board a spacecraft

the central transmitter is a spacecraft downlink transmitter, the central receiver is a spacecraft uplink receiver,

the mobile terminals are landers comprising actuators for movement on a surface of a planet,

the mobile transmitters are lander uplink transmitters, and

the mobile receivers are lander downlink receivers.

3. The system of claim 1 wherein,

the first respective codes are respectively used by the mobile terminals for respectively receiving respective command data from the central transmitter, and

the fourth respective codes are respectively used by the mobile terminals for respectively transmitting respective telemetry data to the central receiver.

4. The system of claim 1 wherein,

the central transceiver is on-board a spacecraft

the central transmitter is a spacecraft downlink transmitter,

the central receiver is a spacecraft uplink receiver,

the mobile terminals are landers comprising actuators for movement on a surface of a planet,

the mobile transmitters are lander uplink transmitters,

the mobile receivers are lander downlink receivers,

the first respective codes are respectively used by the landers for respectively receiving respective command data from the spacecraft downlink transmitter, and

the fourth respective codes are respectively used by the landers for respectively transmitting respective telemetry data to the spacecraft uplink receiver.

5. The system of claim 1 wherein,

the central transceiver is on-board a spacecraft the central transmitter is a spacecraft downlink transmitter,

the central receiver is a spacecraft uplink receiver,

the mobile terminals are landers comprising actuators for movement on a surface of a planet,

the mobile transmitters are lander uplink transmitters,

the mobile receivers are lander downlink receivers,

the first respective codes are WH codes respectively used by the lander downlink receivers for respectively receiving respective command data from the spacecraft downlink transmitter,

the second code in a PN code for fine acquisition of the downlink signal,

the third code is a pilot code for coarse acquisition of the respective downlink signal, and

the fourth respective codes are PN codes respectively used by the lander transmitters for respectively transmitting respective telemetry data in the respective uplink signal to the spacecraft uplink receiver.

6. The system of claim 1 further comprising,

an earth command transmitter for transmitting the command data to the central transmitter,

a central command receiver for receiving the command data and for separating the command data into the respective command data,

a central telemetry transmitter for combining the respective telemetry data into the telemetry data and for transmitting the telemetry data, and

an earth telemetry receiver for receiving the telemetry data.

7. The system of claim 1 wherein each of the mobile transmitters comprise,

a fourth code modulator for modulating the respective fourth codes by the respective telemetry data and providing a respective modulated fourth code signal, and

a phase modulator for phase modulating the uplink carrier by the modulated fourth code signal.

8. The system of claim 1 wherein each of the mobile receivers generate respective ranging data, each of the mobile transmitters comprise,

a fourth code modulator for modulating the respective fourth code by the respective telemetry data and providing a respective modulated fourth code signal,

a summer for modulating the modulated fourth code signal by the respective ranging data, and

a phase modulator for phase modulating the uplink carrier by the modulated fourth code signal.

9. The system of claim 1 wherein each of the mobile receivers comprise,

a third code demodulator for coarsely acquiring the second code,

a second code demodulator for finely acquiring the second code,

a downlink carrier tracking loop for demodulating the downlink carrier signal,

a first code demodulator for demodulating the first code for generating a respective command data signal, and

a data detector for detecting respective command data in the command data signal.

10. The system of claim 1 wherein each of the mobile receivers comprise,

a third code demodulator for coarsely acquiring the second code,

a second code demodulator for finely acquiring the second code,

a downlink carrier tracking loop for demodulating the downlink carrier signal,

a first code demodulator for demodulating the first code for generating a respective command data signal,

a data detector for detecting respective command data in the command data signal, and

an actuator processor for receiving command data and actuating the respective mobile terminal into movement.

11. The system of claim 1 wherein the central receiver, the respective bank uplink receivers each comprise,

a respective fourth code demodulator for demodulating the respective fourth code from the respective uplink signal,

a respective carrier tracking loops for carrier tracking of the uplink carrier of the respective uplink signal, and

respective data detector for detecting the respective telemetry data.

12. The system of claim 1 wherein the central transmitter comprises,

respective first code modulators for modulating the respective first codes by the respective command data for generating respective modulated command data,

a command data summer for summing the respective modulated command data into composite command data,

a second code modulator for modulating the second code by the composite command data for generating modulated code signal,

a quadrature modulator for modulating the downlink carrier by the modulated code signal for generating the first quadrature component,

a third code modulator for modulating a tone level by the third code for generating a modulated third code, and

an inphase modulator for modulating the downlink carrier by the modulated third code for generating the second quadrature component.

13. A system for communicating respective command data from a spacecraft to respective landers over a downlink and for communicating respective telemetry data from the respective landers to the spacecraft over an uplink, the lander having actuators for moving on the surface of a planet, the system comprising,

a spacecraft downlink transmitter on-board the spacecraft for transmitting respective downlink signals over the downlink for communicating the respective command data from the spacecraft to the respective landers, the downlink signals are spectrum spread in quadrature with the respective command data and respective WH codes and a downlink PN code amplitude modulating a downlink carrier on a quadrature component with a pilot code amplitude modulating the downlink carrier on an inphase component, the spacecraft downlink transmitter further for combining the quadrature component and inphase component into the downlink signals,

a spacecraft uplink receiver on-board the spacecraft for receiving respective uplink signals over the uplink communicating the respective telemetry data from the respective landers to the spacecraft, the spacecraft uplink receiver comprising a bank of respective uplink receivers for respectively receiving the respective uplink signals carrying the respective telemetry data from the respective landers,

lander transmitters respectively on-board the respective landers, the lander transmitters transmitting the respective uplink signals over the uplink for transmitting the respective telemetry data from the respective landers to the spacecraft uplink receiver, the respective uplink signals from respective landers are spectrum spread using respective uplink PN codes phase modulating an uplink carrier, and

lander receivers respectively on-board the respective landers, the landers receivers respectively receiving the respective downlink signals over the downlink for respectively receiving the respective command data from the spacecraft downlink transmitter, the respective downlink signals are coarsely acquired using the pilot code on the inphase component, and then finely acquired using the respective WH and PN codes on the quadrature component.

14. The system of claim 13 further comprising,

an earth command transmitter for transmitting the command data to the spacecraft downlink transmitter,

a spacecraft command receiver for receiving the command data and for separating the command data into the respective command data,

a spacecraft telemetry transmitter for combining the respective telemetry data into the telemetry data and for transmitting the telemetry data, and

an earth telemetry receiver for receiving the telemetry data.

15. The system of claim 13 wherein each of the lander transmitters comprise,

a PN code modulator for modulating one of the respective uplink PN codes by the respective telemetry data and providing a respective modulated PN code signal, and

a phase modulator for phase modulating the uplink carrier by the respective modulated PN code signal.

16. The system of claim 13 wherein each of the lander receivers generate respective ranging data from the downlink signals, each of the mobile transmitters comprise,

a PN code modulator for modulating one of the respective uplink PN codes by the respective telemetry data and providing a respective modulated PN code signal,

a summer for modulating the respective modulated PN code signal by the respective ranging data, and

a phase modulator for phase modulating the uplink carrier by the modulated PN code signal.

17. The system of claim 13 wherein the spacecraft uplink receiver, the bank of respective uplink receivers each comprise,

a respective PN code demodulator for demodulating the respective uplink PN codes from the respective uplink signal,

a respective carrier tracking loops for carrier tracking the uplink carrier of the respective uplink signal, and

respective data detectors for detecting the respective telemetry data.

18. The system of claim 13 wherein the spacecraft downlink transmitter comprises,

respective WH code modulators for modulating the respective WH codes by the respective command data for generating respective modulated command data,

a command data summer for summing the respective modulated command data into composite command data,

a downlink PN code modulator for modulating the downlink PN code by the composite command data for generating a modulated code signal,

an inphase modulator for modulating the downlink carrier by the modulated code signal for generating the inphase component,

a pilot code modulator for modulating a tone level by the pilot code for generating a modulated pilot code, and

a quadrature modulator for modulating the downlink carrier by the modulated pilot code for generating the quadrature component.