Radar based terrain and obstacle alerting function

• US 5,945,926 A
• Filed: 05/14/1997
• Issued: 08/31/1999
• Est. Priority Date: 05/14/1996
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Ammar, Danny F., Sweet, Steven R., Spires, Randall C.
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/856,362
• Time in Patent Office: 839 Days
• Field of Search: 340/961, 340/968, 340/970, 340/963, 701/301, 701/120, 701/4, 701/8, 701/9, 701/14, 342/26, 342/29, 342/65
• US Class Current: 340/970
• CPC Class Codes: F41G 7/2226 comparing the observed data with stored target data, e.g. target configuration data
• CPC Class Codes: F41G 7/2246 Active homing systems, i.e. comprising both a transmitter and a receiver
• CPC Class Codes: F41G 7/2286 using radio waves
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01S 13/28 with time compression of received pulses
• CPC Class Codes: G01S 13/4418 with means for eliminating radar-dependent errors in angle measurements, e.g. multipath effects
• CPC Class Codes: G01S 13/4427 with means for eliminating the target-dependent errors in angle measurements, e.g. glint, scintillation effects
• CPC Class Codes: G01S 13/4463 using phased arrays
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 13/913 for landing purposes
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 13/935 for terrain-avoidance
• CPC Class Codes: G01S 13/953 mounted on aircraft
• CPC Class Codes: G01S 2013/0263 Passive array antenna
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G08G 5/0026 located on the ground
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935
• CPC Class Codes: Y02A 90/10 : Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A radar based terrain and obstacle detection device for aircraft detects obstacles and terrain ahead of the aircraft. An alert is sounded if the obstacle or terrain is above a clearance plane positioned ahead of the aircraft.

Claims

1. A method of detecting terrain and obstacles using an aircraft radar comprising the steps of:

providing an airborne radar system configured for transmitting a waveform having parameters for detecting weather data during azimuthal and vertical scans and for processing weather data using a weather detecting algorithm;

interleaving an azimuthal terrain and obstacle detection scan into an azimuthal weather scan by;

interrupting the azimuthal weather scan to switch to a transmitted waveform having parameters suitable for terrain mapping,

collecting a first elevation radar data in a predetermined azimuth sector and centered on an aircraft velocity vector; and

processing said first elevation radar data utilizing a terrain and obstacle detection algorithm;

interleaving a vertical terrain and obstacle detection scan into a vertical weather scan by;

interrupting the vertical weather scan to switch to a transmitted waveform having parameters suitable for terrain mapping;

collecting a second elevation radar data in a predetermined vertical sector and centered on an aircraft velocity vector; and

processing said second elevation radar data utilizing a terrain and obstacle detection algorithm;

defining a clearance plane ahead of said aircraft; and

providing an alert if an obstacle detected in said step of collecting a first and second radar data is located above said clearance plane.

2. The method of claim 1 wherein said step of providing an alert further comprises the step of providing an alert when said obstacle is within a predefined range segment.

3. The method of claim 1 wherein said steps of collecting a first and a second elevation radar data comprises the step of collecting X band radar data.

4. The method of claim 1 wherein said step of collecting a first elevation radar data further comprises the step of classifying a detected target position relative to a predefined buffer zone.

5. The method of claim 1 wherein said azimuth sector includes an offset related to an aircraft crab angle.

6. The method of claim 1 wherein said vertical sector includes an offset related to an aircraft crab angle.

7. The method of claim 1 further comprising the step of displaying a terrain data received during said steps of collecting a first and a second elevation data on a display.

8. The method of claim 1 further comprising the step of displaying said obstacle on a display.

9. A terrain and obstacle detection system for aircraft comprising:

an aircraft weather radar configured for transmitting a waveform having parameters for detecting weather data during azimuthal and vertical weather detection scans and for processing weather data using a weather detecting algorithm;

a radar antenna for collecting a first elevation data in a predetermined azimuth sector centered on an aircraft velocity vector and a second elevation data in a predetermined vertical sector centered on the aircraft velocity vector;

a signal processor for interleaving azimuthal and vertical terrain and obstacle detection scans into azimuthal and vertical weather detection scans by switching from a transmitted signal having parameters suitable for weather detection to a transmitted signal having parameters suitable for terrain and obstacle detection and for resolving said first and said second elevation data into a target data utilizing a terrain and obstacle detection algorithm; and

an alerting device coupled to receive said target data for providing an alert when said target data includes an obstacle located above a clearance plane positioned ahead of the aircraft.

10. The system of claim 9 further comprising a display for displaying said target data.

11. A terrain and obstacle detection device for aircraft comprising:

an input for receiving data from an aircraft weather radar, configured for transmitting a waveform having parameters for detecting weather data during azimuthal and vertical weather detection scans and for processing weather data using a weather detecting algorithm, wherein said data includes a first elevation data in a predetermined azimuth sector and a second elevation data in a predetermined vertical sector;

a signal processor for interleaving azimuthal and vertical terrain and obstacle detection scans into azimuthal and vertical weather detection scans by switching from a transmitted signal having parameters suitable for weather detection to a transmitted signal having parameters suitable for terrain and obstacle detection and for resolving said data from said aircraft weather radar into a target data utilizing a terrain and obstacle detection algorithm; and

an alerting device coupled to receive said target data for providing an alert when said target data includes an obstacle located above a clearance plane positioned ahead of the aircraft.

12. The device of claim 11 further comprising a display for displaying said target data.