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Help me with GPS autopilot that uses NMEA protocol

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asic1984

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hi

there is a sentence in NMEA protocol which is use for autopilot:
$GPAPB,A,A,0.10,R,N,V,V,011,M,DEST,011,M,011,M*82

where:
APB Autopilot format B
A Loran-C blink/SNR warning, general warning
A Loran-C cycle warning
0.10 cross-track error distance
R steer Right to correct (or L for Left)
N cross-track error units - nautical miles (K for kilometers)
V arrival alarm - circle
V arrival alarm - perpendicular
011,M magnetic bearing, origin to destination
DEST destination waypoint ID
011,M magnetic bearing, present position to destination
011,M magnetic heading to steer (bearings could True as 033,T)

is the last field represents the required angle that i must turn from current position to reach the required destination ,and the steer right or left represent direction of this angle?

if this is not correct can someone guide me to how to achieve that

thanks for help
 

asic1984

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gpapb autopilot

hi

thanks but the link is not working
 

IanP

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final year project on automatic pilot

In practice the sentence may look like this:
$GPAPB,A,A,0.1,R,N,,A,300.4,M,WPT001,126.3,M,,*55
where the last field doesn't carry any information, as the gps receiver has to be connected to autopilot computer to know where the destination is and calculate "heading to steer" accordingly.
Just as a reference, here is some info on autopilot function:
https://www.cas-cozy.nl/efis/autopilot.html
Regards,
IanP
 

asic1984

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autopilot gps conection

hi

thanks too much IanP ....u know i decided to put u as a refernce in the documentation of my final year project :)

but i have a question :what if there is aroute recorded in the GPS to folow ,by this the gps now the destination ....will the field of steering give a value?

if this is not correct how can i send the destination to the GPS

i searched for the NMEA protocol most people say that it is only one direction but it seems it is two directional from the graph in the link u send and from other replies for gps questions, how can i use NMEA to uplad and download wayponits and to solve the steering problem if "route" is not correct solution

thanks too much
 

asic1984

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interfacing gps to auto pilot

hi

i found how to send requests using the NMEA protocol but unlucky that my gps device is not support NMEA in ,just out it just support garmin and RTCM for input

what is RTCM?

still donnot know how to get the value required to rotate to reach next destination point from the current direction not with reference of North but with refernce of current direction(i will use pic to interface with gps so i donnot wanna make calculations on it if there is direct way )

while trying the gps with no satellite connection.....i didnot receive the sentence of $GPAPB........is this natural...must be there a connection to receive it .


thanks for help
 

IanP

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nmea autopilot b

RTCM is just another protocol and is used by DGPS (differential correction).

Re. $GPAPB: check in specification of your GPS. It is quite possible that this sentence in not available on your model.
In normal situation if it were available, you would have this sentence present with empty fields (a lot of commas without number in between).

Regards,
IanP
 

    asic1984

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asic1984

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calculate gps autopilot direction

hi

u are right mr IanP .......i thought that when a GPS support NMEA that it support all the sentences.....but this is appear not to be true

there is no $GPAPB in the etrex unit i have

and thanks too mcuh for your help
 

kaustubhkhole

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autopilot used in a sentence

Can any one suggest any book if insted of a plane if there were a CAR ?????
 

hiyan

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auto pilot to gps receiver for robotic

i am not understand autopilot with gps?

can any one briefly explain me what is this ?
 

forrenaissance

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full form of gps in autopilot

Can any one suggest any book please.....
 

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