RF (including GNSS) signal interference mitigation system and method

• US 8,897,407 B2
• Filed: 12/04/2012
• Issued: 11/25/2014
• Est. Priority Date: 12/04/2011
• Status: Active Grant

• Current Assignee: Hemisphere GNSS(USA) Incorporated
• Original Assignee: Hemisphere GNSS(USA) Incorporated
• Inventors: Badke, Bradley P., Whitehead, Michael L., Feller, Walter J., Durnan, Gregory J.
• Primary Examiner(s): Dsouza, Adolf
• Application Number:
  US13/705,018
• Publication Number:
  US 20130142295A1
• Time in Patent Office: 721 Days
• Field of Search: None
• US Class Current: 375/350
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10

Abstract

An RF (e.g., GNSS) interference mitigation system and method uses a switchable bank of filters for selectively blocking signals in predetermined bandwidths based on detecting strong, interfering signals with an interference detection circuit including a sniffer antenna. A low-strength RF (e.g., GNSS) system can be combined with a spectrally-close high-strength, telecommunications receiver system for cooperative control. Alternatively, an RF receiver can detect tones, changes in DC bias or level changes to activate a filter selection switch.

Claims

1. An interference avoidance low noise amplifier (LNA) for a radio frequency (RF) antenna and receiver system, which LNA includes:

multiple bandpass filters selectively connectable to an RF antenna element and to an output connected to an RF receiver, each filter corresponding to a respective RF bandwidth;

a sniffer antenna adapted to detect RF interference signals in a respective RF band;

a logic circuit connected to the sniffer antenna and adapted to select a respective bandwidth based on an interference signal detected by said sniffer antenna;

an automatic switch activated by said logic circuit and adapted to connect said antenna element and said antenna output to a respective bandpass filter;

a receiver selecting the bandwidth selected by the logic circuit for switching out based on a change in direct current (DC) bias;

a solution processor for detecting an interfering signal and switching out a respective frequency bandwidth in response to said detected interfering signal;

said solution processor includes a logic circuit adapted to select the switched-out bandwidth based on interference power;

said logic circuit utilizes multiple bandpass filters for detecting an interfering signal and providing a corresponding signal to said logic circuit for activating a respective filter connected to said antenna element; and

said solution processor including a signal processing function connected to an RF receiver and adapted for selecting a bandwidth in use and blocking a bandwidth not in use by the receiver.

2. The interference avoidance LNA according to claim 1, which includes:

said RF receiver being configured for receiving global navigation satellite system (GNSS) positioning signals.

3. A method of avoiding interference with a low noise amplifier (LNA) for a radio frequency (RF) antenna and receiver system, which method includes:

providing multiple bandpass filters selectively connectable to an RF antenna element and to an output connected to an RF receiver, each filter corresponding to a respective RF bandwidth;

providing a sniffer antenna adapted to detect RF interference signals in a respective RF band;

providing an automatic switch activated by said logic circuit and adapted to connect said antenna element and said antenna output to a respective bandpass filter;

providing a solution processor with a logic circuit for detecting an interfering signal and switching out the bandwidth selected by the logic circuit;

providing a receiver selecting the bandwidth selected by the logic circuit for switching out based on a change in direct current (DC) bias;

said logic circuit utilizing multiple bandpass filters for detecting an interfering signal and providing a corresponding signal to said logic circuit for activating a respective filter connected to said antenna element; and

said solution processor including a signal processing function connected to the RF receiver and adapted for selecting a bandwidth in use and blocking a bandwidth not in use by the receiver.

4. The interference avoidance method according to claim 3, which includes:

said RF receiver receiving global navigation satellite system (GNSS) positioning signals.