Aviacion

For Training Purposes Only

Airborne-Weather-Radar Interpretation

Airborne-Weather-Radar Interpretation Ian Gilbert
This familiarisation is targeted for aircraft equipped with Honeywell weather radar. The fundamental principles are, however, applicable to all weather radars in all aircraft.

Document is not under revision control. All information is subject to the restrictions stated onthe Proprietary Notice.

For Training Purposes Only

Airborne-Weather-Radar Interpretation

Weather-Radar Operating Principles and Interpretation. Presented by Ian Gilbert 1st November 2005

Document is not under revision control. All information is subject to the restrictions stated on the Proprietary Notice.

For Training Purposes Only

Airborne-Weather-Radar Interpretation

RadarPrinciples and Operation

Goals of the Radar: (1) Find the distance to an object (often called a radar target).

(2) To find the direction to the target.

(3) To determine the target’s reflection characteristics.

Here is how it works:

Document is not under revision control. All information is subject to the restrictions stated on the Proprietary Notice.

For Training Purposes OnlyAirborne-Weather-Radar Interpretation

Radar Principles and Operation

The name RADAR is a contraction of the words RAdio Detection And Ranging.
This object is far from the radar. The Radar’s beam envelope.

This object is located near the radar.

Document is not under revision control. All information is subject to the restrictions stated on the Proprietary Notice.

For TrainingPurposes Only

Airborne-Weather-Radar Interpretation

Radar Principles and Operation
The Radar includes a Transmitter, Receiver and Signal processor. Radar’s Display and Control

12 NM
Side view
Transmitted Microwave Energy (about 2 usec)

2 1 3
Radar Target

4

5
Scanning Radar Antenna

Reflected Microwave Energy

Antenna-scan motor

Radar Operator
Radar Target

Outgoingpulse (one radial)

The radar’s beam scans from sideto-side.

Range Rings
15 10

20

Angle indicator lines

5

Expanded Radar Display

Top view of Radarequipped aircraft

Document is not under revision control. All information is subject to the restrictions stated on the Proprietary Notice.

For Training Purposes Only

Airborne-Weather-Radar Interpretation

Here is the mostimportant single point to note:

The dashed line shows where the most reflective part a thunderstorm is located. This red line shows the Radar’s radiation beam envelope

That procedure produces a calibrated-weather presentation. Once you learn the correct technique, operating a weather radar is relatively straight forward.
Document is not under revision control. All information is subject tothe restrictions stated on the Proprietary Notice.

For Training Purposes Only

Airborne-Weather-Radar Interpretation

Radar Principles and Operation - Section 1

(1) Finding the Target’s Distance

Radar-signal-travel time = 12.34 micro seconds per nautical mile. When the radar transmits, it starts keeping track of the travel time. When the signal returns, the round-trip travel time isrecorded. A target at 100 NM range = 1,234 micro seconds travel time.

1 nautical mile = 6,076 feet 1 statute mile = 5,280 feet Speed of light = 186,280 statute miles/second

Let’s take an example:

Document is not under revision control. All information is subject to the restrictions stated on the Proprietary Notice.

For Training Purposes Only

Airborne-Weather-Radar InterpretationRadar Principles and Operation

(1) Finding the Target’s Distance (continued)
Let’s say a target is located at 50 NM. The round-trip travel time to the first target is 617 millionths of a second.
Reflecting objects

50 NM round trip takes the energy 617 micro seconds. 50 NM target 60 NM target

2 micro second (outgoing transmission pulse) 100 NM of radar listening time

B
Target...