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doc:lps:twr-tdma [2017-07-18 15:39] arnaud [Abstract] |
doc:lps:twr-tdma [2017-07-19 11:38] arnaud [Compiling Crazyflie for TWR-TDMA ranging] |
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In order to activate TWR-TDMA, you need to recompile the Crazyflie firmware. Add the following to ' | In order to activate TWR-TDMA, you need to recompile the Crazyflie firmware. Add the following to ' | ||
- | < | + | < |
LPS_TDMA_ENABLE=1 | LPS_TDMA_ENABLE=1 | ||
CFLAGS += -DTDMA_NSLOTS_BITS=1 | CFLAGS += -DTDMA_NSLOTS_BITS=1 | ||
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* **LPS_TDMA_ENABLE=1** Enable the TDMA mode for TWR | * **LPS_TDMA_ENABLE=1** Enable the TDMA mode for TWR | ||
- | * **TDMA_NSLOTS_BITS=1** Configures 2 time slot (good for 2 tags). The number of time slot is 2^TDMA_NSLOTS_BITS | + | * **TDMA_NSLOTS_BITS=1** Configures 2 time slot (good for 2 tags) per frame. The number of time slot per frame is 2^TDMA_NSLOTS_BITS |
- | * **TDMA_SLOT** Optionally hardcode the time slot. See bellow for time slot auto-configuration. | + | * **TDMA_SLOT** Optionally hardcode the time slot. See bellow for time slot auto-configuration |
===== Configuring time slots ===== | ===== Configuring time slots ===== | ||
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===== System performance ===== | ===== System performance ===== | ||
- | TWR-TDMA is currently implemented with time slots of 4ms. Each time slot is used by one tag to range with one anchor. This means that the ranging rate is of //1/(0.004 * (2^TDMA_NSLOTS_BITS)// | + | TWR-TDMA is currently implemented with time slots of 4ms. Each time slot is used by one tag to range with one anchor. This means that the ranging rate is of //1/(0.004 * 2^TDMA_NSLOTS_BITS)// |
- | The more timeslots, the less often measurements can be used to estimate the tag position and so the performance of the position estimate will deteriorate. For a great number of tag the [[doc: | + | The more timeslots |