Method and apparatus for automatic distress call signal transmission

• US 4,547,778 A
• Filed: 06/09/1981
• Issued: 10/15/1985
• Est. Priority Date: 06/09/1981
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: O'Hagan, Michael, Hinkle, Robert W.
• Primary Examiner(s): Blum, Theodore M.
• Assistant Examiner(s): Kaiser, K. R.
• Application Number:
  US06/271,915
• Time in Patent Office: 1,589 Days
• Field of Search: 455/54, 455/63, 455/96, 455/98, 343/103, 343/106 D, 343/112 TC, 343/108 R, 343/102, 343/386, 343/389, 343/402, 343/405, 343/410, 343/456, 179/1 SM, 179/1 SA, 381/51-53, 340/539
• US Class Current: 342/456
• CPC Class Codes: G01S 1/24 the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations , e.g. LORAN systems
• CPC Class Codes: G01S 1/685 using pulse modulation, e.g. pulse frequency modulation

Abstract

A method and apparatus for determining the position of a vessel in distress and transmitting an auditory distress message containing the position of the vessel. The apparatus obtains the position of the vessel as determined by a LORAN-C type receiver from either a cassette or directly from the LORAN-C receiver and generates a "Mayday" message including the identification of a vessel, the position of the vessel and the nature of the emergency. The "Mayday" message is synthesized into an auditory human or Morse code message. The language of the auditory message is preferably chosen to correspond with the most likely language used by a possible receiver of the "Mayday" message. Also preferably, the apparatus determines whether the primary distress radio frequency is clear; should the primary distress frequency be in use, the apparatus automatically shifts to a secondary frequency and transmits the "Mayday" message. During transmission on the secondary frequency the apparatus continues to monitor primary frequency; when the primary frequency clears, the "Mayday" message is transmitted thereon.

Claims

1. A method of automatically producing a distress call on board a craft comprising

(a) automatically monitoring an alarm network for an alarm signal and in response to said alarm signal, automatically;

(b) obtaining digitized absolute position information of said craft from a position determining means on board said craft;

(c) obtaining digitized information from a data bank informative of the craft identification and nature of the distress;

(d) determining the closest land based station and the prevailing language used by the station for the distress call;

(e) creating a distress call in the prevailing language of the closest land based station from the information and memory addresses therefor;

(f) coupling the addresses for the distress call to the memory of a speech synthesizer for producing the distress call in a human speech using the prevailing language used by the closest land station; and

(g) activating a radio for radio transmission of the distress call in human speech using the prevailing language used by the closest land station.

2. A method of automatically producing a distress call according to claim 1 further including automatically monitoring the radio transmitter for determining whether an emergency channel frequency is available for tansmission and automatically selecting an alternative frequency for transmission until the emergency channel frequency is clear.

3. A distress call producing apparatus comprising:

(a) a digital means for obtaining and digitizing information for a distress call including vessel identification and the actual carrier position information;

(b) a speech synthesizer means including an addressable memory having word and phrase information and a synthesizer said addressable memory of the speech synthesizer means containing words and/or phrases in a plurality of human languages;

(c) a radio frequency transmitter operably connected to the speech synthesizer means; and

(d) a center means including a control means operatively connected to;

the data bank means for obtaining the digitized information, the position determining means for obtaining the digitized present location of the carrier and to the transmitter for selecting an emergency channel frequency, said control means including means for determining the closest land based station and the prevailing human language spoken there and for addressing the addressable memory to locate words or phrases or both in the prevailing human language for the synthesizer, said control means operable to format a distress call from the digitized information received from the data bank and position determining means and produce in proper sequence memory addresses, said addressable memory of the speech synthesizer means operable in response to the addresses of the control means to activate the synthesizer of the speech synthesizer means for producing the distress call in the prevailing human language of the closest station for transmission by the transmitter means on the selected frequency.

4. A distress call producing apparatus according to claim 3 wherein said control means includes loop back means for selecting a plurality of human languages for sequential transmission.

5. A distress call producing apparatus according to claim 4 wherein the control means includes a means for monitoring the emergency channel frequency and selecting a secondary frequency for transmission until the emergency channel frequency is clear and the selecting the emergency channel frequency for transmission.