From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 22 Oct 2015 02:53:25 +0200 From: Andrew Lunn Message-ID: <20151022005325.GB930@lunn.ch> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [B.A.T.M.A.N.] Alfred GPS higher update rate List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: The list for a Better Approach To Mobile Ad-hoc Networking On Thu, Oct 22, 2015 at 11:07:48AM +1300, Keith Chew wrote: > Hi > > I am experimenting with using Alfred on a group of drones (initially > 10 units) to send their GPS locations to each other. > > The drones will be connected via batman-adv on WIFI, and each of them > read the GPS every 200ms (5Hz). > > I would like to change alfred-gpsd from updating the GPS coordinates > every 10s to 200ms. > > Does anyone see any issues with this change? ie it is even feasible/practical? You need to change more than alfred-gpsd. The core alfred server does updates every 10 seconds. You need to change ALFRED_INTERVAL so that it will propagate GPS data faster. If you want 200ms, i doubt such a change would be accepted back to the core code. So you probably need to add a command line option to allow setting this interval. alfred-gpsd will also need some changes. It currently updated the information in alfred every 2 seconds. You will need to modify this as well. When i wrote the alfred-gpsd code, i was not particularly interested in fast updates. So you might need to change the architecture a little. In particular, i knew gpsd was giving fixes much faster than alfred would distribute them, so i didn't tell alfred about every change. You might need this. Andrew