Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [gps]

Global Positioning System consists of a group of satellites that are used in conjunction with special purpose receivers to calculate a precise location. It is often used for aircraft navigation purposes.

-1
votes
1answer
83 views

Will the IFR Grade GPS be an requirement in the future?

This question is directly related to my other question so I have to ask it I think its obvious why I ask this if you read that question but I will repeat myself again. Station based navigation is ...
0
votes
2answers
134 views

What technologies exist to find an aircraft position after it crashed out of line of sight? [closed]

What is the best way in the manner of products to find an aircraft after it crashed out of line of sight. Are there defined standards, and what are the selection criteria?
3
votes
1answer
131 views

Is there any plan to create GPS approaches to water areas for seaplanes?

Is anyone working on differential GPS approaches for seaplanes? They are a largely ignored resource with great capabilities for certain remote places
0
votes
1answer
77 views

What does mean 'GS' in RNAV (GPS) Chart?

Hello. I have a question about 'GS' in my RNAV(GPS) Approach Chart. Usually, (Including PAPI, VASI whatever...) Normal Glide Descent Angle means 3.00 degree. but some 'GS' says 3.07, 3.04, 3.09 ...
2
votes
2answers
123 views

What is the difference between RTK GPS and GBAS?

My understanding is that real-time kinematic (RTK) is also a differential GPS technology to enhance accuracy by using a ground-based station to provide the correction data to the onboard GPS receiver. ...
2
votes
2answers
257 views

What did Fiji have to do when it incorporated GPS into its aviation system?

I'm reading the BBC's How Fiji changed the way we travel; The little Pacific island nation was the first to incorporate GPS into its aviation system – and in doing so forever changed the way we get ...
0
votes
1answer
98 views

Will a non-certified GPS source work the same in ADS-B mandated airspace?

What happens if you use a non-WAAS GPS position source in ADS-B mandated airspace? Doesn't it work the same, except for the positional accuracy?
1
vote
4answers
315 views

Is smart phone's GPS accurate enough to calculate airplane speed? [closed]

Around seven years ago, I did airplane speed measurement. I activated the GPS on my tablet and I monitored the speed, especially when the airplane touched the ground (runway). I found that the ...
7
votes
2answers
2k views

What is a blind encoder?

As I'm studying, I found that GPS has to have 5 satellites or 4 satellites with "blind encoders" to use RAIM. What is a blind encoder and what is its purpose?
5
votes
1answer
444 views

What are the considerations for coding the GPS before engine start without external power?

Suppose I would need 10-15 minutes to fully configure my G1000 on a C172 ahead of a flight, with the flight plan, my personal view settings, etc., and prefer to do that before starting the engine. My ...
6
votes
2answers
1k views

How to navigate an aircraft without GPS? [duplicate]

In case of loss of GPS: how can an aircraft not only be navigated but navigated so precisely that it can pinpoint its destination airport ? (case in point: Finland and Norway are telling airline ...
17
votes
3answers
2k views

Are NDBs and VORs dying as a navigational method?

I am new to aviation, so bear with me on this question: I have read in multiple places that the VOR/NDB navigational aids are dying out to GPS. Is this true? Are more modern aircraft being built with ...
6
votes
1answer
186 views

If a SID chart says “GPS… required”, can the plane use a different GNSS?

This US/FAA standard instrument departure says "Note: GPS or DME/DME/IRU required." If the aircraft could tune into a different GNSS like GLONASS, could the pilot still legally fly the departure ...
4
votes
1answer
494 views

Why would a Mode-C transponder report a different altitude than an altimeter/GPS?

This is related to a small single-engined plane. On a recent flight, the controller kept telling me that I was 300 ft higher than it appeared on my altimeter and GPS (which were in sync). This was ...
5
votes
2answers
718 views

How can I tell a GPS installation is acceptable for IFR use?

I am evaluating an aircraft for use under IFR. I want to know if the GPS that is installed is acceptable for use under IFR. I have access to the logbooks and documentation. I want to check: That ...
2
votes
1answer
116 views

Position update rate of GPS [closed]

GPS satellites send data at the rate of 50 bits per second. One GPS subframe is 6 seconds long. How is it possible to update one's position faster than once in 30 seconds when we require the whole ...
3
votes
1answer
169 views

How do you program circular flight plans in GPS?

In a recent Buzzfeed article about aerial surveillance, I have seen a map showing perfectly circular flight patterns. Given how precise the patterns are, I highly doubt that the aircraft were being ...
3
votes
1answer
587 views

Is a non-WAAS Garmin 530 certified for an LNAV/VNAV approach?

I may not understand all the details of what I'm asking but trying to wrap my head around it. I am aware that before WAAS, some GPS aircraft were equipped to get vertical guidance by a Barocorrected ...
3
votes
2answers
343 views

Does the altitude or attitude of an aircraft affect GPS accuracy?

Of course we are assuming an effective signal is being received. I live near Idaho Falls, Idaho with a field elev of 5300ft. If I shoot an approach will GPS be more or less accurate then landing at ...
2
votes
1answer
190 views

Why is there a provision of pressure setting in GPS?

Some of the GPS have a provision of setting barometric pressure (QNH/QFE). How does it work?
49
votes
5answers
11k views

In the rare event that the U.S. DOD shuts off the GPS, what's the alternative?

In the U.S., the Department of Defense along with other Federal Agencies of the Government operates & maintains the GPS. In the rarest of the events, if for any reason whatsoever, the Government ...
9
votes
1answer
566 views

When should I start turning in this circling approach?

I've been practicing circling approaches in Homestead General Aviation Airport in Homestead, Florida (X51). I performed the RNAV (GPS) RWY 10 approach with circling minimums. My questions are: a) ...
1
vote
1answer
575 views

What are the WAAS requirements for RNAV (GPS) approaches?

Is a WAAS GPS required to fly in RNP airspace (e.g., RNAV (GPS) approaches)? Or, can you be approved to fly RNAV (GPS) approaches with, say a military EGI (embedded GPS/INS)?
3
votes
1answer
2k views

What are the lateral sensitivities of GPS approaches?

What are the lateral sensitivities of each of the WAAS and LNAV approach? Is the lateral sensitivity of WAAS the same as that of the localizer, which is 3 to 6 degrees? What about the LNAV approach?
0
votes
0answers
196 views

What is the correlation between RNP level and the CDI indication?

I got a question regarding the connection between RNP (required navigational performance) accuracy and cdi sensitivity of the HSI. According to the instrument flying handbook the standard for RNP on ...
5
votes
2answers
557 views

Can the iPad use GPS data from a Garmin aera 660?

Can the iPad use GPS data from a Garmin aera 660 portable GPS unit? I assume this would happen via Bluetooth, if it's possible. I would like the more accurate WAAS data from the Garmin for use with ...
4
votes
1answer
301 views

Why is there a GPS/RNAV waypoint co-located with a VOR?

There is an RNAV waypoint named STYCK co-located at what appears to be the exact location of the LOA VOR (coordinates match precisely as well). Why would the creation of a waypoint be necessary if IFR ...
7
votes
1answer
241 views

How can I check that the GPS receiver is sending data to the transponder?

I fly an ultralight aircraft. The GPS is a puck-type device from which the TX line runs to the mode-s transponder. The transponder does not readily show if it is receiving position data. The data is ...
-2
votes
1answer
248 views

Why don't transponders send gps coordinates and other important info in addition to altitude and transponder code?

I heard that they were waiting for the patent holder's patent to expire, but just wanted to confirm.
4
votes
2answers
202 views

Should the route be changed if the GPS RAIM prediction fails?

Do i have to change the route if the GPS RAIM prediction has one or more outages along my route?
7
votes
1answer
428 views

Is a “GPS required” ILS (or other navaid-based) approach considered a “GPS approach” for alternate planning's sake when TSO-C129/196 gear is in use?

If you have TSO-C129/TSO-C196 GPS gear (vs TSO-C145/146 WAAS/SBAS gear), you either have to have a non-GPS approach at your destination, or a non-GPS approach at your alternate. If your choices are ...
2
votes
1answer
567 views

Why do Computer Navigation Fixes still exist now that GPS waypoints can be used to define tracks?

A CNF is a point that defines a navigation track for a GPS, but why is it used when you there are GPS waypoints that are created to define a track?
4
votes
1answer
654 views

How to leverage Lynx NGT-9000's integrated GPS/WAAS?

I’m inheriting an IFR capable 1964 Cherokee 235 that is not equipped with a GPS. I’m looking at installing a Lynx NGT-9000 to get ADS-B compliant and gain the traffic and weather information. Is ...
4
votes
3answers
3k views

How does Kalman filtering work in inertial navigation systems?

As far as I understood it correctly most INS-systems use a Kalman filter to compensate measurement errors. I would like to know: Does the Kalman filter compensate the errors from all the onboard ...
4
votes
1answer
1k views

Why does Boeing 737 use 2 Inertial Reference Systems (IRS) and GPS?

According to this website the Boeing 737 aircraft use 2 IRS and 2 GPS: IRS L & IRS R. Why? Apparently they are totally independent of each other. Could somebody explain a little bit why they need ...
5
votes
1answer
2k views

Why are there GPS MOCAs?

The Pilot Controller Glossary (and other places) define MOCAs as: MINIMUM OBSTRUCTION CLEARANCE ALTITUDE (MOCA)− The lowest published altitude in effect between radio fixes on VOR airways, off-...
9
votes
2answers
6k views

Can a pilot use their GPS/FMS to fly a VOR or NDB approach?

GPS is more accurate than a VOR or NDB signal. Can we use a GPS to fly a VOR or NDB approach from the initial approach fix through the missed approach and hold? I know there are two types of ...
1
vote
1answer
596 views

Is GPS considered to be a navigational facility for the purposes of Ops Spec C055?

For 14 CFR 119 certificate holders, Alternate Airport IFR Weather Minimums are prescribed by Operations Specification (Ops Spec) C055, specifically Table 1 of that specification. Below is a generic ...
3
votes
1answer
668 views

Are ADS-B Airborne Squitters inherently inaccurate?

Right now I am reading related passages/sections from ICAO Annex 10 Volume 4 and Technical provisions for Mode S Extended squitter. Airborne position squitters are randomly distributed in between 0.4 ...
2
votes
4answers
2k views

How to convert a pressure height (ADS-B) to a geometric height?

As far as I know, ADS-B broadcast a pressure altitude, so I want convert it to geometric one. How is it possible? e.g in MSG format: http://adsb-decode-guide.readthedocs.io/en/latest/position.html ...
5
votes
1answer
355 views

Is there any reason to have ADS-B out that is not based on GPS?

The ADS-B system is only as accurate as the location data source it uses. In the US the 2020 ADS-B mandate requires that horizontal location data be from a GPS source with minimum performance ...
4
votes
2answers
855 views

Do modern aircraft still have mechanical sensors as backup to GPS?

A comment here Why does "no aircraft cross directly over the pole"? indicates that modern aircraft use GPS for navigational purposes, which makes perfect sense. However, do these aircraft ...
-1
votes
2answers
185 views

Which frame of reference is used to calculate ground velocity? [closed]

During flight, in which frame the ground velocity components are calculated? in the body frame or in the earth frame?
4
votes
1answer
507 views

Why did my phone's GPS receiver stop working when the plane was descending to land?

Recently, I flew on an Airbus A320. I turned my Lenovo A328 Android phone into airplane mode, and then used the default Maps app to watch my position using GPS. For most of the flight it worked ...
4
votes
1answer
192 views

Why might a moving map Android app consistently record altitude off by 120 feet?

I fly Cessna 172 and Cherokee Warrior both older models without a GPS. I have a very useful freeware navigation app on my android phone which is really good in every regard other than it always reads ...
2
votes
3answers
378 views

What is the best way to retrieve (and transmit) location (GPS) of plane in real time?

What are some of the best ways to retrieve and transmit the location of a plane I am in, real time. To speak in realistic terms, I'm currently training for my private pilot's license and as such am ...
5
votes
2answers
468 views

Can I use my non-WAAS GPS receiver with ADS-B in the United States?

I have a older style Garmin 530. Can I use this GPS as the position source for an ADS-B installation?
0
votes
2answers
870 views

How does GPS measure any plane's ground speed?

How does GPS measure an equipped airplane's ground speed assuming that the plane in question actually uses GPS as opposed to an inertial navigation system or other method? (This was originally part ...
24
votes
13answers
10k views

How did planes measure their speed relative to the ground before GPS?

How did planes measure their ground speed before GPS? If they used some sort of anemometer to measure speed, that would only measure the speed of the plane relative to the air through which it is ...
10
votes
1answer
509 views

How does an FMS shift after losing all external navaids?

It's not uncommon for polar flights to lose GPS signal (ionosphere issues due to the high latitudes). But it is not a concern because the typical IRS drift is 650 meters for every hour of flight, and ...