Automatic VSWR sensing for aircraft-mounted pulse radar systems
OwnerWarren Bruce Cope, Mark G. Roosinventors
Life of this patent
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Abstract
An aircraft mounted pulse radar unit transmits a low-energy, test output pulse and processes the resulting test return signal to determine the VSWR and whether the VSWR exceeds a predetermined threshold. If the VSWR exceeds the threshold, the unit prevents transmission of a nominal energy output pulse which might result in damage to the receiver due to an excessive energy level of the return signal. In one embodiment, the unit uses the VSWR to determine and enable output signals at reduced power levels such that energy levels of any return signals would be insufficient to damage the receiver.
Claims20
In an aircraft-mounted, radar frequency unit including a transmitter operable for transmitting a radar frequency output signal at a nominal energy level, a receiver operable for receiving and processing a return signal resulting from transmission of the output signal, and control means for controlling the energy level of the output signal, a method of operating the unit comprising the steps of:
- (a) preceding transmission of an output signal at a nominal energy level, transmitting a test output signal presenting an energy level such that the maximum energy level of a resulting test return signal is less than a maximum allowable level;
- (b) for a test return signal, determining whether the energy level of said test return signal exceeds a predetermined threshold, such being indicative that a nominal energy level output signal would result in a return signal energy level exceeding said allowable level;
- and
- (c) if said test return signal energy level exceeds said threshold, preventing transmission of a nominal energy level output signal.
In an aircraft-mounted, radar frequency unit including a transmitter operable for transmitting a radar frequency output signal at a nominal energy level, a receiver operable for receiving and processing a return signal resulting from transmission of the output signal, and control means for controlling the energy level of the output signal, a method of operating the unit comprising the steps of:
- (a) transmitting a test output signal presenting an energy level about one fourth of the energy level of a nominal energy level output signal such that the maximum energy level of a resulting test return signal is less than a maximum allowable level;
- (b) for a test return signal, determining whether the energy level of said test return signal exceeds a predetermined threshold, such being indicative that a nominal energy level output signal would result in a return signal energy level exceeding said allowable level;
- and
- (c) if said test return signal energy level exceeds said threshold, preventing transmission of a nominal energy level output signal.
In an aircraft-mounted, radar frequency unit including a transmitter operable for transmitting a radar frequency output signal at a nominal energy level, said output signal being a pulse presenting an amplitude and a time pulse width, a receiver operable for receiving and processing a return signal resulting from transmission of the output signal, and control means for controlling the energy level of the output signal, a method of operating the unit comprising the steps of:
- (a) transmitting a test output signal having about one fourth the pulse width of the nominal energy level output signal such that the maximum energy level of a resulting test return signal is less than a maximum allowable level;
- (b) for a test return signal, determining whether the energy level of said test return signal exceeds a predetermined threshold, such being indicative that a nominal energy level output signal would result in a return signal energy level exceeding said allowable level;
- and
- (c) if said test return signal energy level exceeds said threshold, preventing transmission of a nominal energy level output signal.
In an aircraft-mounted, radar frequency unit including a transmitter operable for transmitting a radar frequency output signal at a nominal energy level, said output signal being a pulse presenting an amplitude and a time pulse width, a receiver operable for receiving and processing a return signal resulting from transmission of the output signal, and microprocessor control means for controlling the energy level of the output signal in accordance with a computer program stored in memory, a method of operating the unit comprising the steps of:
- (a) transmitting a test output signal as a pulse having a pulse width less than that of a nominal energy level output signal such that the maximum energy level of a resulting test return signal is less than a maximum allowable level, said maximum allowable level being an energy level above which the receiver is subject to damage;
- (b) for a test return signal, determining the VSWR of said test output signal and said test return signal and determining whether said VSWR exceeds a predetermined VSWR threshold, such being indicative that a nominal energy level output signal would result in a return signal energy level exceeding said allowable level;
- (c) if said VSWR exceeds said threshold, preventing transmission of a nominal energy level output signal;
- and
- said method including the step of implementing steps (a)-(c) in accordance with a computer program stored in memory.
An aircraft mounted radar apparatus comprising:
- transmitter means for transmitting a radar frequency output signal at a nominal energy level;
- receiver means for receiving and processing a return signal resulting from transmission of an output signal;
- and
- control means for controlling the operation of said transmitter and receiver means, said control means including means for
- controlling the transmission of a test output signal presenting an energy level such that the maximum energy level of a resulting test return signal is less than a maximum allowable level, transmission of said test output signal preceding transmission of said nominal energy level signal;
- for a test return signal, determining whether the energy level of said test return signal exceeds a predetermined threshold, such being indicative that a nominal energy level output signal would result in a return signal energy level exceeding said allowable level;
- and
- if said test return signal energy level exceeds said threshold, preventing transmission of a nominal energy level output signal.
Dependencies are inferred from the claim text.