Platform transmitter terminal (PTT) for use with an ARGOS type satellite system and utilizing a solar array/rechargeable battery power source

• US 4,731,870 A
• Filed: 11/23/1984
• Issued: 03/15/1988
• Est. Priority Date: 11/23/1984
• Status: Expired due to Fees

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Daniels, John, Black, Harold D., Strikwerda, Thomas E., Levanon, Nadav
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Kuntz, Curtis
• Application Number:
  US06/674,128
• Time in Patent Office: 1,208 Days
• Field of Search: 455/127, 455/117, 455/113, 455/119, 455/12, 455/98, 455/100, 340/870.39, 340/870.28
• US Class Current: 455/127.5
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/1607 Supply circuits converters H02M; filters therefor H02M1/14; voltage stabilisers G05F1/46
• CPC Class Codes: H04B 7/18517 Transmission equipment in earth stations
• CPC Class Codes: H04B 7/18576 Satellite systems for providing narrowband data service to fixed or mobile stations, e.g. using a minisatellite, a microsatellite for selecting H04W

Abstract

An improved platform transmitter terminal (PTT) is disclosed for use in an ARGOS type satellite system. The PTT has reduced size, weight and extended life due to a solar array/rechargeable battery power source operating under the supervision of a unique power supply control and protection means. The invented PTT, when used in an ARGOS type system, opens the possibility of tracking, on a global basis, wild animals weighing as little as a few kilograms.

Claims

1. A portable transmitter for transmitting information to an earth satellite, comprising:

a rechargeable battery;

a solar array operably connected to said battery for charging said rechargeable battery;

a transmitter means for sending information to a satellite; and

,

a load control means operably connected to said rechargeable battery and said transmitter means, for operably actuating said transmitter means when the voltage level of said rechargeable battery reaches a first threshold level and for deactivating said transmitter means when the voltage level of said rechargeable battery subsequently falls to a second lower threshold level, wherein said load control means further includes a controller means, for sequentially applying power to components of said transmitter means during each transmission cycle that said transmitter means is actuated.

6. The apparatus of claim 1, wherein said transmitter means includes:

a temperature compensated crystal oscillator for generating a reference signal;

a dividing phase lock loop means, phase locked to said reference signal, for generating a desired carrier signal;

a power amplifier means operably connected to said dividing phase lock loop means for amplifying said desired output signal; and

,

an antenna coupled to said power amplifier for emitting said desired output signal.

7. The apparatus of claim 6, wherein said controller means first supplies power to said temperature compensated crystal oscillator, second supplies power to said dividing phase lock loop means, and then supplies power to said power amplifier means, during each transmission cycle.

8. The apparatus of claim 7, wherein said temperature compensated crystal oscillator is supplied with power at a certain time interval before said power amplifier means is actuated, said time interval set to allow said temperature compensated crystal oscillator sufficient time to warm up and stabilize.

9. The apparatus of claim 6, wherein said dividing phase lock loop means further includes:

a voltage control oscillator operating at the carrier frequency;

a divide circuit operably connected to said voltage control oscillator;

a phase detection means, operably connected to said temperature compensated crystal oscillator, and said divide circuit, for generating an error signal; and

,

a loop amplifier operably connected to said phase detection means, for generating the control voltage to said voltage control oscillator.

10. The apparatus of claim 9, further including a phase modulator operably coupled to said loop amplifier, for switching offset voltages to said loop amplifier, thereby modulating said output signal.

11. The apparatus of claim 10, further including a central controller means operably coupled to said phase modulator, for switching said offset voltages, thereby transmitting sync bits, a transmitter identification code, and sensor information data.

2. A portable transmitter for transmitting information to an earth satellite, comprising:

a rechargeable battery;

a solar array operably connected to said battery for charging said rechargeable battery;

a transmitter means for sending information to a satellite; and

,

a load control means operably connected to said rechargeable battery and said transmiter means, for operably actuating said transmitter means when the voltage level of said rechargeable battery reaches a first threshold level and for deactivating said transmitter means when the voltage level of said rechargeable battery subsequently falls to a second lower threshold level, wherein said load control means further includes a charge rate control means, operably connected to said solar array and said rechargeable battery, for switching a current limiting means in series with said solar array when the voltage level of said rechargeable battery reaches a first threshold level and for switching out said current limiting means when the voltage lelvel of said rechargeable battery subsequently falls to a second lower threshold level.

3. The apparatus of claim 2, wherein said first threshold level associated with said charge rate control means is set to a voltage level indicating full charge of said rechargeable battery.

4. A portable transmitter for transmitting information to an earth satellite, comprising:

a rechargeable battery;

a solar array connected to said battery for charging said rechargeable battery;

a transmitter means for sending information to a satellite; and

,

a load control means operably connected to said rechargeable battery and said transmitter means, for operably actuating said transmitter means when the voltage level of said rechargeable battery reaches a first threahold level and for deactivating said transmitter means when the voltage level of said rechargeable battery subsequently falls to a second lower threshold level, wherein said load control means further includes a protection means for switching a discharge load in series with said rechargeable battery when said transmitter means produces a continuous signal over a certain time signal in excess of a set standard, and for switching out said discharge load when the voltage level of said rechargeable battery subsequently falls below a certain threshold.

5. The apparatus of claim 4, wherein said protection means switches out said discharge load prior to depletion of said rechargeable battery.

12. A portable transmitter for transmitting information to an earth satellite, comprising:

a rechargeable battery;

a solar array operably connected to said rechargeable battery for charging said rechargeable battery;

a transmitter means for sending information to a satellite;

a load control means operably connected to said rechargeable battery and said transmitter means, for operably actuating said transmitter means when the voltage level of said rechargeable battery reaches a first threshold level and for deactuating said transmitter means when the voltage level of said rechargeable battery subsequently falls to a lower threshold level;

a charge rate control means, operably connected to said solar array and said rechargeable battery, for switching a current limiting means in series with said solar array when the voltage level of said rechargeable battery reaches a first threshold level and for switching out said current limiting means when the voltage level of said rechargeable battery subsequently falls to a second lower threshold level; and

,

a protection means for switching a discharging load in series with said rechargeable battery, when said transmitter means produces a continuous signal over a certain time interval in excess of a set standard, and for switching out said discharge load when the voltage level of said rechargeable battery falls below a certain threshold level.

13. The apparatus of claim 12, wherein said transmitter means includes:

a temperature compensated crystal oscillator for generating a reference signal;

a dividing phase lock loop means, phase locked to said reference signal for generating a desired carrier signal;

a power amplifier means operably connected to said dividing phase lock loop means for amplifying said desired output signal; and

,

an antenna coupled to said power amplifier for emitting said output signal.

14. The apparatus of claim 13, wherein said load control means further includes a controller means, for sequentially applying power to components of said transmitter means during each transmitter transmission cycle in accordance with the following sequence:

first, supply power to said temperature compensated crystal oscillator second, supply power to said dividing phase lock loop means, and then supply power to said power amplifier.

15. The apparatus of claim 14, wherein said temperature compensated crystal oscillator is supplied with power at a certain interval before said power amplifier is powered, said time interval set to allow said temperature compensated crystal oscillator sufficient time to warm up and stabilize.