Receiver mask cut-off angles

[Kerry.]

Could we have some indications of what the mask cut-off angles for different receivers might be.

 

Do have values for many receivers but in addition would appreciate the make/model, software version, mask angle and the method that angle was determined. The actual method used to determine the cut-off is important.

 

WAAS has obviously changed many manufacturer's thinking with regard the application of mask angle parameters. Mask cut-off angles were also re-accessed recently on an international basis as far as differential systems are concerned.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[peter]

I haven't tried to determine the exact mask angles of my receivers (III+, eMap) yet, but have noticed that when using 'battery-saver' mode one of the effects is to stop searching for satellites at low angles (i.e. increase the mask angle).

[+GOT GPS?]

Reciever Mask angle:

 

alot depends on the quality of the GPS unit.

I have several Magellans and Garmins, and find that the GPS V is better.

 

Quality and Precision are a factor in how the reciever works.

 

This is a Military secure site, but no password needed:

https://www.spacecom.af.mil/GPS_Support/archive/Frontpage/effect_of_Terrain_on_Mask.htm

(GPS Suport Center)

 

https://www.spacecom.af.mil/GPS_Support/technical_notes.htm

 

 

 

Google Search:

http://www.google.com/search?sourceid=navclient&ie=UTF-8&oe=UTF-8&q=GPS+mask+angle

 

[This message was edited by GOT GPS? on April 24, 2003 at 02:26 AM.]

[+Poindexter]

The mask angle for the Northstar 941X marine GPS receiver is user adjustable from 0° to 25° in 5° increments. The default is 10° These are high quality $1500.00 units.

[Kerry.]

Poindexter, yeah it's interesting in just who provides user definable masks and who doesn't.

 

Maybe it's a good query to put to some of the manufacturers who don't allow this function. Maybe they don't want to make it sound confusing, maybe there's this wider community myth that the more satellites a receiever sees/uses, the better it is, more is best type syndrome even if Sats are contributing anything constructive (sometimes destructive) to the solution.

 

Lowrance was originally 10 degrees, I'm intersted in what they are now as well.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[+apersson850]

Takes a lot of testing, but I assume I could get myself a fairly good idea by looking at the elevation displayed by VisualGPS, for the satellites that the Vista does display. The mask angle is altered when you set it to battery save mode, to avoid spending power on CPU cycles, hunting for hard-to-get satellites near the horizon.

 

I would guess that the eTrex Vista has something like 5º and 15º mask angle, depending upon the operation mode. This is then from just observing when sats seem to disappear from the screen, and taking notes of the lowest angles which are displayed in the different modes.

 

Anders