RF/digital signal-separating GNSS receiver and manufacturing method

• US 9,178,573 B2
• Filed: 03/19/2013
• Issued: 11/03/2015
• Est. Priority Date: 02/02/2010
• Status: Active Grant

• Current Assignee: Hemisphere GNSS(USA) Incorporated
• Original Assignee: Hemisphere GNSS(USA) Incorporated
• Inventors: Feller, Walter J.
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): Singh, Amneet
• Application Number:
  US13/847,429
• Publication Number:
  US 20140125518A1
• Time in Patent Office: 959 Days
• US Class Current: 1/1
• 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 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: H04B 1/0028 wherein the AD/DA conversion occurs at baseband stage
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 7/00 Radio transmission systems, i.e. using radiation field H04B10/00, H04B15/00 take precedence

Abstract

An RF/digital signal-separating receiver is provided for GNSS and other RF signals. The receiver includes a first master antenna and a second slave antenna, which are positioned in spaced relation for directional, radio compass applications. First and second downconverters and first and second ADCs are located under the first and second antennas in analog signal areas, which configuration minimizes cross-coupling RF signals from the antennas and reduces noise. The first and second ADSs are connected to respective first and second correlators in a digital signal location, which is centrally located relative to the antennas. The correlators are connected to a microprocessor for computing distances for the received signals, from which the receiver'"'"'s orientation or attitude is determined. A method of manufacturing receivers with this configuration is also disclosed.

Claims

1. A method of reducing internally generated digital noise in an RF/digital directional receiver, which method comprises the steps of physically:

providing first and second antennas positioned in spaced relation in said receiver;

providing first and second RF downconverters each located directly adjacent and connected via a common printed circuit board (PCB) to a respective antenna;

providing first and second analog-to-digital converters (ADCs) each connected via a common PCB to a respective downconverter;

locating said first and second downconverters and said first and second ADCs in a first analog signal area under said first antenna and a second analog signal area under said second antenna respectively;

providing a digital signal area, adjacent to said first and second analog signal areas, located centrally relative to said first and second antennas;

providing first and second correlators in said digital signal central location and connected to said first and second ADCs respectively;

providing a microprocessor in said digital signal central location and connected to and receiving input from said first and second correlators using low voltage differential signal (LVDS) lines;

processing analog signals in said first and second analog signal areas under said first and second antennas, respectively;

processing digital signals in said digital signal central location;

providing first and second low noise amplifiers (LNAs) connected to said first and second antennas and to said first and second downconverters respectively;

providing first and second shielded LVDS lines between said first and second ADCs in said first and second analog signal areas under said antennas and said first and second correlators in said digital signal central location respectively; and

communicating digital signals from said first and second ADCs to said first and second correlators over said first and second LVDS lines respectively;

wherein the physical arrangement of the antennas, LNAs, downconverters and ADCs in said first and second analog signal areas, the correlators and microprocessor in said digital signal area, and the use of the LVDS lines to connect the ADCs with the correlators on the common PCB reduces the internally generated digital noise in the RF/digital directional receiver.

2. The method according to claim 1, further comprising the steps:

providing a single-axis gyro located within said analog section;

providing at least one tilt sensor connected to said single-axis gyro and actively monitoring said single-axis gyro; and

connecting said tilt sensor to said microprocessor using at least one LVDS line.

3. A GNSS compass for use with a vehicle, said compass comprising:

a single common printed circuit board (PCB) including a first analog signal portion, a second analog signal portion, and a digital signal portion adjacent said first and second analog signal portions and located centrally relative to said first and second analog signal portions;

first and second antennas positioned in spaced relation and located within said first and second analog signal portions of said PCB, respectively;

first and second RF downconverters each located directly adjacent and under, and connected via said PCB to, said first antenna within said first analog signal portion, and said second antenna within said second analog signal portion, respectively;

first and second analog-to-digital converters (ADCs) each connected via said PCB to a respective downconverter within said first analog signal portion and said second analog signal portion, respectively, and each located under said first antenna and said second antenna, respectively;

first and second correlators located in said digital signal portion and connected to said first and second ADCs respectively;

a microprocessor located in said digital signal portion and connected to and receiving input from said first and second correlators using low-voltage differential signal (LVDS) lines;

first and second low noise amplifiers (LNAs) connected to said first and second antennas and to said first and second downconverters respectively;

providing first and second shielded LVDS lines between said first and second ADCs in said first and second analog signal portions under said first and second antennas and said first and second correlators in said digital signal portion respectively;

wherein analog signals are generated within said first and second analog signal portions;

wherein digital signals are processed within said digital signal portion;

a housing containing said PCB and all components connected to said PCB; and

wherein the location and heading of a vehicle to which said housing is affixed is calculated by said microprocessor.

4. The GNSS compass of claim 3, further comprising:

a single-axis gyro located within at least one analog signal portion;

at least one tilt sensor connected to said single-axis gyro and actively monitoring said single-axis gyro;

wherein said tilt sensor is connected to said microprocessor using at least one LVDS line; and

wherein the heave, pitch and roll of the vehicle is calculated by said microprocessor.

5. The GNSS compass of claim 3, wherein said vehicle is a marine vehicle.