GPWS vs EGPWS: Difference and Comparison

Comparing the early ages with the present, you will realize how several modes of transportation have changed drastically. The most wholesome has been the upgrade in aircraft and air transportation that we can agree has made our lives easier.

The following article talks about the difference between GPWS and EGPWS, both of which make aircraft safer and more efficient.

Key Takeaways

1. Ground Proximity Warning System (GPWS) alerts pilots to potential ground collisions using radio altimeter data, while Enhanced GPWS (EGPWS) adds terrain and obstacle databases for improved accuracy.
2. EGPWS provides a “look-ahead” function that anticipates terrain ahead of the aircraft, while GPWS does not offer this feature.
3. EGPWS reduces the risk of false alarms and increases situational awareness compared to GPWS, leading to improved safety.

GPWS vs EGPWS

GPWS is an older technology that uses radar altimeters to monitor the aircraft’s altitude above the ground. The system provides an audible and visual warning to the pilot. EGPWS is an advanced version of GPWS that uses a combination of GPS, terrain databases, and other sensors to provide more precise information about the aircraft’s position and the surrounding terrain.

 GPWS stands for the ground proximity warning system. Its primary function is to keep track of the safety limits and precautions. If they are being violated or breached, it alerts the pilot.

These include warnings and safety precautions if the plane is too close to the ground or travelling at an unnatural speed.

EGWPS is the advanced form of GPWS, except it provides more security. Since EGWPS can monitor not just the base directly underneath but also around and above, it has a better control and prediction protocol.

Both GPWS and EGPWS are used to monitor accurate information on the location and positioning of the aircraft.

Comparison Table

Parameters of Comparison	GPWS	EGPWS
Full form	It stands for Ground Proximity Warning System.	It stands for Enhanced Proximity Ground Warning System.
Definition	A system designed by aircraft engineers and pilots to ensure that the aircraft does not pose a threat of running into the ground causing damage.	It protects the landing and take-off of the flight by informing the pilots of the obstacles in the way and the general landform of the land they are flying over.
Domain	GPWS is only capable of gathering information on the land just underneath it, meaning it has a small range of focus.	EGPWS is capable of collecting information on a vast stretch of land underneath and around the aircraft, which means it has a larger range of focus.
Advance feature	GPWS is the traditional form of protection and does not use GPS.	EGPWS is the more upgraded form of protection and uses GPS.
TDS- Terrain Database System	GPWS does not make use of the Terrain database system.	EGPWS makes use of the Terrain database system.

What is GPWS? 

The discovery of ground evaluating sensors became more prominent after the early 1960s; there were a large number of accidents both in the air and on water.

The US government took notice and realized these could have been avoided had there been proper navigation and the obstacles were acknowledged. Hence, GPWS came. 

GPWS is precautionary equipment that is used to respond to the pilots about the terrain condition over which the aircraft is flying. During an alert or warning generated by the system, it is up to the crew and pilots to create a safety protocol.

This may include alignment and slowing down or landing elsewhere. Also known as the Terrain Awareness Warning System, a GPWS informs the pilot about any obstacles on the ground.

Care must be taken if the course of the flight is such that it is steep and not steadily controllable. In such a case, the reaction time to the warning may be reduced, which can lead to severe accidents.

Since the focus of the GPWS is narrow, it can gather information on only the part of the ground right underneath the aircraft. This means that the time between the warning and the course of action is minimal as it is. 

What is EGPWS?

EGPWS is the advanced version of GPWS. It is more secure and has an increased and imputed time between the identification of the obstacle and the safety protocol.

Advanced as it is, it uses GPS and has a broad focus range. The location on the earth’s database is considered and parallel to the same computers that generate and predict the location of the obstacles.

It is faster, more efficient, and covers a larger area.

It uses the Terrain display technology that produces the highest and lowest point of the landform, considering which the aircraft can either come low or improve its flying level.

The Terrain Database system also enables the EGPWS system to sense the obstacles and elevation of landforms further on, which is even more precautionary and safer for the pilots and the people on board.

Main Differences Between GPWS and EGPWS 

1. Both GPWS and EGPWS are used for aircraft protection from accidents and damages. However, EGPWS is advanced, while GPWS is the traditional form of the same. EGWPS uses modern and more detailed algorithms, landform comparison sheets, and better equipment in construction.
2. Both GPWS and EGWPS use the Continuous Wave Radar technology, where the waves are emitted from the aircraft, picked up by the ground, and then reflected. The time is calculated, and the magnanimity and the distance between the plane and the obstacle are predicted. The difference between these waves’ transmissions and reflections is that they are more accurately received and interpreted in the case of EGWPS. 
3. GPS consists of an air data system, inertial reference unit, instrumental landing system, altimeters, receiving, and reflecting surfaces. EGWPS uses all the same but also includes a Global Positioning device (GPS). 
4. One significant difference between the two is the GWPS would be able to register the presence of any building or obstacle even if it is recently built. Since EGWPS is based on GPS and datasheet technology, the presence of the new building or obstacle has to be updated in the sheet. The reference landform sheet should be updated for EGWPS to perform effectively. 
5. GPWS uses sensors to determine the presence of obstacles, while EGPWS uses a terrain database system. 

References

1. https://upcommons.upc.edu/bitstream/handle/2117/340863/EGPWS.pdf?sequence=1
2. https://ieeexplore.ieee.org/abstract/document/738350/