How do I use RAIM prediction?
· On the Flight Plan menu, click RAIM Prediction. Receiver Autonomous Integrity Monitoring (RAIM ) assesses the integrity of the Global Positioning System (GPS) signals. This system predicts outages for a specified geographical area. These predictions are based on the location, path, and scheduled GPS satellite outages.
What is the N-RAIM prediction service?
Since 2006, the N-RAIM Prediction Service, hosted by NAVBLUE, offers worldwide coverage for all PBN applications including RNP 10, RNAV 5, RNAV 2, RNAV 1, RNP 4, RNP 1, RNP Approach and RNP AR Approach down to 0.1NM. The online tool is an alternative to the automated service integrated directly into flight planning software.
What is the free RAIM/FDE prediction service?
Garmin provides this free RAIM/FDE Prediction service to provide high quality prediction which takes into account the performance of Garmin GPS receivers. All fields required. errorFactor (Optional. 0 is no error introduced, 1.0 is maximum error introduced.)
What is RAIM and why is it important?
Unsourced material may be challenged and removed. Receiver autonomous integrity monitoring ( RAIM) is a technology developed to assess the integrity of global positioning system (GPS) signals in a GPS receiver system. It is of special importance in safety-critical GPS applications, such as in aviation or marine navigation .
What is RAIM and when is it required?
RAIM stands for Receiver Autonomous Integrity Monitor. It is a part of aviation graded GPS receivers that checks consistency of all used GPS satellite signals in order to raise an alert if the GPS system is not working correctly. For RAIM to work, there must be at least 5 usable satellites in view of the GPS receiver.
What is RAIM used for?
RAIM stands for receiver autonomous integrity monitoring, a technology used in GNSS receivers to assess the integrity of the GNSS signals that are being received at any given time. It is particularly applicable to receivers intended for safety-critical applications, and in particular in aviation applications.
What does RAIM check mean?
Receiver autonomous integrity monitoring (RAIM) is a technology developed to assess the integrity of global positioning system (GPS) signals in a GPS receiver system. It is of special importance in safety-critical GPS applications, such as in aviation or marine navigation.
What happens if RAIM is lost in flight?
The RAIM (Receiver autonomous integrity monitoring) is what allows you to fly using a GPS. If you lose RAIM, by regulations you cannot use the GPS to navigate.
Is RAIM required for LPV?
En route, you can check RAIM if you're planning to fly to LNAV minimums. But RAIM can't tell you if you'll have sufficient signal quality to fly to LPV minimums, so there's no need to check it if you plan to fly to LPV approach or LNAV/VNAV minimums.
What is WAAS and RAIM?
7. Federal Aviation. Administration. Receiver Autonomous Integrity Monitoring (RAIM)
Is RAIM prediction required?
IFR GPS units must automatically perform a RAIM check before beginning an approach. However, performing a RAIM check prior to leaving the ground will better enable pilots to plan ahead and is recommended specifically for pilots without baro-aiding (see below).
How long is a RAIM check valid?
+/- 15 minutesWhilst a RAIM check may be performed in the aircraft, the result is only valid for +/- 15 minutes.
How many satellites are required for RAIM?
A minimum of five satellites is required to detect a bad satellite; at least six satellites are required to detect and exclude a bad satellite from the navigation solution if your receiver has a fault detection and exclusion (FDE) RAIM algorithm.
What must you do if RAIM fails while you are enroute?
What must you do if RAIM fails while you are en route on an IFR flight plan? A. You must inform ATC and either cancel IFR or request a special VFR (SVFR) clearance.
What approaches can you fly with RAIM?
RAIM equipped aircraft are IFR legal as long as it's TSO certified. WAAS equipped aircraft, they allow us to fly pretty much anything GPS related like I already said.
How does RAIM prediction work?
RAIM Prediction is based on the current almanac of the coarse orbit information of the entire satellite network. When you select an arrival time at a specific waypoint, as in the GNS 530W below, it advances the satellite positions along their orbits to determine which satellites are in view there (which ones and how many). From the geometry of their location and yours, a dilution of precision can be calculated and an estimate made of how good your solution will be. This prediction uses certain criteria to determine whether RAIM will be available or not. On the 530W it will do this calculation and give you an answer. That prediction is shown below, along with RAIM prediction from an FAA website (raimprediction.net). The FAA prediction is for a 24 hour window.
What is a raim check?
A RAIM check determines whether you meet the Horizontal Protection Limit (HPL) requirements for your phase of flight, which are 2 nm Enroute, 1 nm Terminal, or 0.3 nm for non-precision approaches. These checks are being done continuously (autonomous measurements) to determine your integrity at all times (by comparing the pseudoranges to a number of satellites). If you fail to meet the requirements, messages must be given to the pilot (each receiver does this differently).
Do you need a RAIM check on a TSO C146?
If have a TSO C146 WAAS receiver there is no requirement for a RAIM check unless you have a WAAS failure or are out of the coverage area. Then, you must meet the above requirements. For that reason there must be a way to check RAIM in these receivers. But if you're getting WAAS corrections, your HPL is still being checked. And since you can do vertical approaches with the receiver it also checks your VPL (Vertical Protection Limit).
How is RAIM calculated?
RAIM can be continuously calculated by the receiver by determining a position with four satellites and then recalculating using a fifth satellite to substitute for one of the other satellites. This process is accomplished by the fifth satellite replacing one of the other satellites at a time, and comparing the five resulting position differences.
Is RAIM available for enroute?
The likelihood of RAIM not being available for enroute and terminals navigation is much higher and for all practical purposes is 100 percent. Some GPS receivers have a more advanced version of RAIM that includes Fault Detection and Exclusion (FDE) capability.
Is it a good idea to check a raim?
It is a good idea to check RAIM as part of the preflight planning for a flight using a non WAAS GPS, but I have not found where it is required. If you are aware of RAIM outages for a given airport at a particular planned arrival time, you can change the departure time to one that RAIM is anticipated to be available, or you can adjust your planned route to use ground based navigation aids.
Overview
RAIM prediction websites
To enable pilots to quickly determine whether en route or approach level RAIM will be available, the FAA and EUROCONTROL have created "dispatch level" websites that predict RAIM status to meet pre-flight check requirements.
• The FAA's RAIM prediction website "AC 90–100" covers US territories in graphical map format (showing green for RAIM available and red for RAIM not available)
General description
RAIM detects faults with redundant GPS pseudorange measurements. That is, when more satellites are available than needed to produce a position fix, the extra pseudoranges should all be consistent with the computed position. A pseudorange that differs significantly from the expected value (i.e., an outlier) may indicate a fault of the associated satellite or another signal integrity problem (e.g., ionospheric dispersion). Traditional RAIM uses fault detection (FD) only, however …
External links
• ADS-B & RAIM PREDICTION: FAA ADS-B and AC90-100A GPS RAIM Service Availability Prediction Tool (SAPT).
• Worldwide Coverage from the FAA.
• AUGUR: the Eurocontrol GPS RAIM prediction tool.