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Questions tagged [gnss]

GNSS is a global satellite navigation system. GPS is the US GNSS.

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0answers
106 views

What's the busiest airport that's not WGS-84 compliant?

Most latitude and longitude coordinates are defined relative to the WGS-84 standard, including GPS coordinates from your receiver. However, some coordinates are specified using local datums, and ...
2
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1answer
75 views

Does EASA allow using a portable GPS for RNAV capability?

Assume an older IFR-certified aircraft with the classical equipment, that is two VOR/ILS receivers with plain CDIs, ADF and DME, but no GPS. It can be flown IFR, but many routes can't be used, because ...
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12answers
30k views

Why don't all commercial aircraft transmit GPS data in real time?

It seems strange that trucks and taxis can be set up to transmit GPS data in real time but aircraft cannot. Wouldn't this be a useful function and feasible to implement?
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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?
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2answers
695 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 ...
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2answers
217 views

Can a GPS waypoint be used when filing a VFR flight plan?

This probably equally applies to IFR flight plans, but the general question is can arbitrary (unrelated to an airway or named fix) GPS coordinates be used in the route on a flight plan?
3
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2answers
121 views

Can jetliner pilots program departures when specific RNAV procedures do not exist?

Can commercial pilots (e.g. 737 and 737 Max) program departures into their on-board GPS navigation system for the first portion of a flight that doesn't have specific RNAV procedures?
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2answers
157 views

What are the ICAO GNSS waypoint naming conventions?

I'm curious about ICAO naming conventions regarding GNSS and RNAV waypoints. Would I be correct in assuming that all GNSS area waypoints are 5 letters, and RNAV waypoints are 6? What about waypoints ...
2
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1answer
106 views

Does a GPS OBS selector use magnetic or true courses?

Under GPS navigation, when we are using the OBS to tune courses. Are these courses magnetic or true?
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6answers
4k views

What's the minimum number of sensors for a hobby GPS waypoint-following UAV?

I would like to develop my own guidance, navigation and control (GN&C) flight software on a Raspberry Pi, for a small hobby fixed-wing UAV. From a physical standpoint, what is the minimum set of ...
2
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1answer
786 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 ...
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2answers
266 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 ...
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0answers
58 views

Compute great-circle track from longitude

The Aviation Formulary defines Clairut's formula to compute the intermediate track (bearing) for a GC based upon latitude, but any given GC (ignoring one passing through the poles), crosses a given ...
7
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1answer
246 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
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1answer
108 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 ...
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2answers
138 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?
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3answers
3k views

What makes flight recorders harder to find than tagged sharks?

It really bothers me that we can't find planes that weigh tons with black boxes (AFAIK) technology that's almost obsolete, on the other hand shark tags (AFAIK) work great for long time and we can ...
4
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1answer
584 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 ...
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5answers
8k views

Why is there a difference between GPS Speed and Indicator speed?

I just played with flight simulator and noticed that the GPS shows different speed from the speed indicator in the cockpit. Also, GPS speed is higher than the Indicator. Any Idea why?
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1answer
129 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 ...
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2answers
289 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. ...
3
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2answers
305 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 ...
28
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6answers
19k views

How do airliners cross the ocean without GPS?

How do airliners cross the ocean without GPS? Do they use dead-reckoning or are there navigation aids floating out there?
5
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1answer
200 views

What does “zero offset between two waypoints” mean in ICAO Doc 4444?

My question is with reference to the GNSS based separation specified in ICAO Doc 4444. Could someone explain the significance/meaning of the condition "zero offset between two waypoints" criteria? if ...
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4answers
16k views

Is LPV considered a precision approach?

WAAS LPV approaches can have decision altitudes as low as 200 AGL, the same as many Cat I ILS approaches. Previous opinions on the Internet have quoted the FAA as saying LPV is considered a non-...
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1answer
102 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?
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2answers
506 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?
4
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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 ...
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4answers
358 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 ...
28
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6answers
16k views

Is it possible for a modern commercial airliner to stop being tracked without substantial mechanical failure?

I was speaking to someone about the MH370 incident, and they suggested that a hijacker could turn off the device that sends the plane's current position, resulting in the appearance of a catastrophic ...
2
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1answer
128 views

What is the difference between EPE and HUL on the Satellite Status Page of GNS systems?

For exemple on the GNS430 satellite status page you can read, in addition to the GPS receiver status : EPE (Estimated Position Error) DOP (Dilution of Precision) HUL (Horizontal Uncertainty level) ...
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0answers
89 views

What is the area coverage of a RAIM availability prediction check?

For example on GNS430 you have a RAIM availability prediction tool : one must enter a waypoint, date and time to compute RAIM availability prediction at +-15min. How big is the area around the ...
5
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1answer
464 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
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2answers
2k 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 ...
16
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3answers
6k views

Why isn't an LPV SBAS approach considered a precision approach according to ICAO?

According to ICAO's classification, LPV SBAS approach is in the APV group, because it doesn't meet some specifications for precision approaches. But what exactly does it not meet? Glossary: LPV: ...
2
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1answer
439 views

How do GLS avionics plot an entire accurate approach path?

I'm studying wireless navigation systems, especially GBAS. I have gone through some ICAO documents regarding GBAS. From what I have read, FAS data is included in Message Type 4. Closer examination of ...
3
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1answer
3k views

Is GLS (GBAS landing system) an RNAV approach?

PBN which is contrast to conventional navigation consists of RNAV and RNP. And I know that general RNAV approach of IAP has up to 4 minima such as LPV, LNAV, LNAV/VNAV, and LP. And I know that GLS ...
17
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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 ...
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3answers
128 views

Are there (ideas for) GNSS based attitude indicators?

With upcoming GNSS systems that have better accuracy than GPS, could there be an GNSS based attitude indicator? Does maybe one already exist? I could imagine having 4 sensors (front, aft, left ...
5
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2answers
4k views

Can I use an expired IFR-certified GPS with an out of date database in lieu of DME?

I know I should update the database in my GPS, but nevertheless I'm wondering if i can use an expired IFR-certified GPS with an out-of-date database in lieu of DME
7
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1answer
222 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 ...
5
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1answer
721 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 ...
6
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2answers
1k 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
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1answer
170 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
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1answer
183 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 ...
5
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2answers
269 views

Is the Bendix/King KMD-550 airplane icon always oriented to the north?

I have a 2001 Cessna 182T with King avionics. The KMD-550 moving map display correctly shows "track up" but the little airplane icon is always pointed to the north. How can I set this so that it ...
37
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9answers
44k views

“Airplane mode” does not disable GPS… is it safe to use GPS in flight?

I noticed that even when my phone is in "airplane mode", I can still use the GPS. Theoretically a GPS receiver just receives data, so I guess it would not jam anything. On the contrary, on the ...
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3answers
1k views

Why do planes need line of sight for GPS to work?

Why is the below true when mobile devices such as mobile phones and designer watches with emergency beacons work without Line of sight? Most commercial aircraft transmit their GPS-based position ...
3
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1answer
727 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 ...
1
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1answer
495 views

Are there any precision approaches that use only GNSS/LAAS?

Is there any airport which has a precision instrument approach using only GNSS (augmented with LAAS) for guidance?