Low probability of detection emergency signaling system and method
First Claim
Patent Images
1. A method of transmitting an emergency distress signal while maintaining a low probability of detection profile, the method comprising:
- detecting an emergency indication at an emergency transmitter;
transmitting a first low probability of detection encoded radio frequency spread-spectrum signal using a first power level and a first spreading factor selected to provide a local communications range, the transmitting being from the emergency transmitter in response to the emergency indication;
waiting a time interval for reception of a confirmation message at the emergency transmitter in response to the first low probability of detection encoded radio frequency spread-spectrum signal;
transmitting a second low probability of detection encoded radio frequency spread-spectrum signal using a second power level wherein the second power level is greater than the first power level to provide an extended communications range if no response signal was received at the emergency transceiver during the time interval, the extended communications range being greater than the local communications range.
2 Assignments
0 Petitions
Accused Products
Abstract
An emergency locating system can include emergency transceivers and rescue transceivers. The emergency transceivers can be capable of repeat transmission of a distress message using a variable power level and variable spreading factor. A receive transceiver can be capable of receiving the distress messages and sending a confirmation message to the emergency transceiver. The emergency transceiver can be capable of receiving the confirmation message and terminating transmission of the distress message.
24 Citations
30 Claims
-
1. A method of transmitting an emergency distress signal while maintaining a low probability of detection profile, the method comprising:
-
detecting an emergency indication at an emergency transmitter; transmitting a first low probability of detection encoded radio frequency spread-spectrum signal using a first power level and a first spreading factor selected to provide a local communications range, the transmitting being from the emergency transmitter in response to the emergency indication; waiting a time interval for reception of a confirmation message at the emergency transmitter in response to the first low probability of detection encoded radio frequency spread-spectrum signal; transmitting a second low probability of detection encoded radio frequency spread-spectrum signal using a second power level wherein the second power level is greater than the first power level to provide an extended communications range if no response signal was received at the emergency transceiver during the time interval, the extended communications range being greater than the local communications range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A portable emergency transceiver for search and rescue operations in a hostile environment, the transceiver comprising:
-
a wearable device; a transmitter disposed in the wearable device and capable of repeated transmission of a unique unit identification using a low probability of detection radio frequency waveform with a variable power level and a variable spreading factor; an actuator disposed in the wearable device and operatively coupled to the transceiver to enable transmission from the transmitter when the actuator is operated according to a predefined authorization methodology; and a receiver disposed in the wearable device and operatively coupled to the transmitter and capable of receiving confirmation messages via a radio frequency link, wherein the receiver controls the variable power level and variable spreading factor based on reception and non-reception of confirmation messages. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
-
-
28. A search and rescue system comprising:
-
(a) a plurality of emergency transceiver units, each emergency transceiver unit comprising; (i) a transmitter configured to transmit a distress message comprising a unique unit identification using a low probability of detection radio frequency waveform with a variable power level and a variable spreading factor when actuated; and (ii) a receiver operatively coupled to the transmitter and configured to control the transmitter power level and spreading factor based on the reception and non-reception of confirmation messages in response to the transmitted unique unit identification; (b) a plurality of rescue transceiver units, each rescue transceiver unit comprising; (i) a receiver configured to receive a distress message from any one of the plurality of emergency transceiver units; and (ii) a transmitter operatively coupled to the receiver and configured to transmit a confirmation message in response to the reception of a distress message. - View Dependent Claims (29, 30)
-
Specification