Questions tagged [raim]

Receiver Autonomous Integrity Monitoring is a technology developed to assess the integrity of GPS signals in GPS receiver systems.

Filter by
Sorted by
Tagged with
1 vote
0 answers

RAIM Checks when using GNSS in lieu of DME for distance information

I understand that a RAIM has to be checked on the ground as part of preflight, as well as before the commencement of an RNAV/RNP approach. What I am unable to find information on online, is whether a ...
Zhi Hao Tan's user avatar
5 votes
1 answer

Why do some GPS receivers suppress RAIM integrity warnings after you pass the FAF?

RAIM performs an integrity check 2NM from the FAF. If RAIM is lost before the FAF, one should execute the missed approach. However, if RAIM is lost after passing the FAF, some GPS receivers will ...
JoeyMo's user avatar
  • 51
1 vote
1 answer

Why are SBAS-equipped planes exempt from the preflight prediction check?

My question stems from this other question: Why is training regarding the loss of RAIM given so much more emphasis than training regarding the loss of SBAS? Two answers say losing RAIM puts a question ...
user avatar
4 votes
1 answer

Why do ADS-B outages occur without simultaneous RAIM outages?

If you check the ADS-B prediction tool and the RAIM prediciton tool on SAPT.FAA.GOV you will see far more ADS-B outages. What causes ADS-B outages to occur at different times than RAIM outages? Are ...
Ryan Mortensen's user avatar
7 votes
2 answers

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?
Mun Park's user avatar
  • 477
5 votes
2 answers

Must RAIM be checked in flight before every GPS approach or is a preflight check acceptable?

My instructor has been teaching me to run a RAIM check for each RNAV approach we do. For some flights this can be 4 or more RAIM checks for the various airports/approaches and adds significantly to ...
John's user avatar
  • 1,405
8 votes
3 answers

How is GPS RAIM availability calculated?

I recently had someone ask me if there was a GPS RAIM availability calculator available for the iPad. There isn't, but it got me thinking that I could write one. After doing some searching, I can't ...
Lnafziger's user avatar
  • 58.5k