Continues Ranging and update rate

[metehanemlik]

I want to make continues ranging to make this:

ı changed

PRINTLN(F(" Ranging all anchors. Return to IDLE"));
updateState(STATE_IDLE);

to

PRINTLN(F(" Ranging all anchors. Return to IDLE"));
updateState(STATE_PONG);

and ı add some code to calculateRange function amd then received Continues Ranging like this:

123 , 158 , 182 , 93 , 96
31 , 158 , 185 , 93 , 96
31 , 158 , 185 , 85 , 96
30 , 158 , 185 , 85 , 100
123 , 153 , 185 , 85 , 100
31 , 153 , 194 , 85 , 100
31 , 153 , 194 , 88 , 100
30 , 153 , 194 , 88 , 99
121 , 150 , 194 , 88 , 99
31 , 150 , 172 , 88 , 99
31 , 150 , 172 , 93 , 99
30 , 150 , 172 , 93 , 99
123 , 151 , 172 , 93 , 99
31 , 151 , 170 , 93 , 99

the first row is delay time for every calculateRange(); others are anchors distance(cm)

as you can see sometimes there is a big delay like 120ms,

we can eliminate this delay?

whole code:

void calculateRange() {
DW1000Time round1 = (timePollAckReceived - timePollSent).wrap();
DW1000Time reply1 = (timePollAckSent - timePollReceived).wrap();
DW1000Time round2 = (timeRangeReceived - timePollAckSent).wrap();
DW1000Time reply2 = (timeRangeSent - timePollAckReceived).wrap();
DW1000Time tof = (round1 * round2 - reply1 * reply2)
/ (round1 + round2 + reply1 + reply2);
distance[idx_anchor] = tof.getAsMeters();
if(calHz == 0){
currentMillis = millis();
calHz = 1;
Serial.print( millis() - currentMillis2);
Serial.print(" , ");
}else{
calHz = 0;
currentMillis2 = millis();
Serial.print( millis() - currentMillis);
Serial.print(" , ");
}
Serial.print(round(distance[0]*100));
Serial.print(" , ");
Serial.print(round(distance[1]*100));
Serial.print(" , ");
Serial.print(round(distance[2]*100));
Serial.print(" , ");
Serial.println(round(distance[3]*100));
}

[somidad]

Any reason that you skipped STATE_SCAN state?

[metehanemlik]

Any reason that you skipped STATE_SCAN state?

STATE_SCAN is working on startup one time

[somidad]

Did you check side effect that you skip STATE_SCAN and go directly to STATE_PONG after ranging is completed? e.g.,

• https://github.com/gsongsong/dw1000-positioning/blob/master/tagArduino/tagArduino.ino#L249-L266
• https://github.com/gsongsong/dw1000-positioning/blob/master/tagArduino/tagArduino.ino#L355-L373

Currently, I don't have RPi, Arduino nor dwm1000. Hence, I can't guarantee there is no side effect. So please debug it.

[metehanemlik]

the code is working as a continuously but to complete ranging with 4 anchors Arduino needs 140ms.

I changed also to reduce delay 100 > 30
#define PONG_TIMEOUT_MS 30

Also, some times there is noisy ranging. I need accurate and fast ranging.

Do you any advice for filter or fast ranging?

[hknckr]

Hi Metehan, I am also working with DWM1000 modules for a week. There is a method called TDOA(Time Difference of Arrival) But clock sync is needed for anchors in this method. It is not easy. I am working to find a way to achieve this. In TDOA tag is almost passive, just sends a blink message then everything is up to anchors. Anchors positions are known positions. So system calculates TDOAs. With this method you can have more faster ranging. I haven't used this library yet but I think tag blinks and then waits anchors to calcualte and send back some information so it cause delays.